Datasheet TOP243P, TOP243G, TOP243G-TL, TOP242Y, TOP242R-TL Datasheet (Power Integrations)

®

®

TOP242-249

TOPSwitch -GX

Family

Extended Power, Design Flexible,

EcoSmart

®

, Integrated Off-line Switcher

July 2001

Figure 1. Typical Flyback Application.

PRODUCT

3

Adapter

1

Open

Frame

2

Open

Frame

2

OUTPUT POWER TABLE

Table 1. Notes: 1. Typical continuous power in a non-ventilated
enclosed adapter measured at 50 °C ambient. Assumes 1 sq. in. of
2 oz. copper heat sink area for R package. 2. Maximum practical
continuous power in an open frame design at 50 °C ambient. See
Key Applications for detailed conditions. Assumes 3 sq. in. of 2 oz.
copper heat sink area for R package. 3. See Part Ordering Information.

4. 230 VAC or 100/115 VAC with doubler.

PI-2632-060200

AC

IN

DC

OUT

D

S

C

TOPSwitch-GX

CONTROL

L

+

-

FX

230 VAC ±15%

4

Adapter

1

85-265 VAC

9 W 15 W 6.5 W 10 W
10 W 22 W 7 W 14 W
10 W 22 W 7 W 14 W

13 W 25 W 9 W 15 W
20 W 43 W 15 W 23 W
13 W 45 W 15 W 30 W

16 W 30 W 11 W 20 W
28 W 52 W 18 W 28 W
30 W 65 W 20 W 45 W

33 W 58 W 20 W 32 W
40 W 85 W 26 W 60 W

37 W 65 W 24 W 36 W
60 W 125 W 40 W 90 W

41 W 73 W 26 W 43 W
85 W 165 W 55 W 125 W

43 W 78 W 28 W 48 W

105 W 205 W 70 W 155 W

45 W 82 W 30 W 52 W

120 W 250 W 80 W 180 W

Product Highlights

Lower System Cost, High Design Flexibility

• Extended power range to 250 W

• Features eliminate or reduce cost of external components

• Fully integrated soft-start for minimum stress/overshoot

• Externally programmable accurate current limit

• Wider duty cycle for more power, smaller input capacitor

• Separate line sense and current limit pins on Y/R packages

• Line under-voltage (UV) detection: no turn off glitches

• Line overvoltage (OV) shutdown extends line surge limit

• Line feed forward with maximum duty cycle (DC

MAX

)

reduction rejects line ripple and limits DC

MAX

at high line

• Frequency jittering reduces EMI and EMI filtering costs

• Regulates to zero load without dummy loading

• 132 kHz frequency reduces transformer/power supply size

• Half frequency option in Y/R packages for video applications

• Hysteretic thermal shutdown for automatic fault recovery

• Large thermal hysteresis prevents PC board overheating

EcoSmart

- Energy Efficient

• Extremely low consumption in remote off mode
(80 mW @ 110 VAC, 160 mW @ 230 VAC)

• Frequency lowered with load for high standby efficiency

• Allows shutdown/wake-up via LAN/input port

Description

TOPSwitch-GX uses the same proven topology as TOPSwitch,
cost effectively integrating the high voltage power MOSFET,
PWM control, fault protection and other control circuitry onto
a single CMOS chip. Many new functions are integrated to
reduce system cost and improve design flexibility, performance
and energy efficiency.

Depending on package type, the TOPSwitch-GX family has
either 1 or 3 additional pins over the standard DRAIN, SOURCE
and CONTROL terminals. allowing the following functions:
line sensing (OV/UV, line feedforward/DC max reduction),
accurate externally set current limit, remote on/off, and
synchronization to an external lower frequency and frequency
selection (132 kHz/66 kHz).

All package types provide the following transparent features:
Soft-start, 132 kHz switching frequency (automatically reduced
at light load), frequency jittering for lower EMI, wider DC

MAX

,
hysteretic thermal shutdown and larger creepage packages. In
addition, all critical parameters (i.e. current limit, frequency,
PWM gain) have tighter temperature and absolute tolerance, to
simplify design and optimize system cost.

TOP242 P or G

TOP242 R
TOP242 Y

TOP243 P or G

TOP243 R
TOP243 Y

TOP244 P or G

TOP244 R
TOP244 Y

TOP245 R
TOP245 Y

TOP246 R
TOP246 Y

TOP247 R
TOP247 Y

TOP248 R
TOP248 Y

TOP249 R
TOP249 Y

TOP242-249

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Section List

Functional Block Diagram......................................................................................................................................... 3

Pin Functional Description........................................................................................................................................ 4

TOPSwitch-GX Family Functional Description ........................................................................................................5

CONTROL (C) Pin Operation .................................................................................................................................6

Oscillator and Switching Frequency .......................................................................................................................6

Pulse Width Modulator and Maximum Duty Cycle ................................................................................................. 7

Light Load Frequency Reduction............................................................................................................................7

Error Amplifier......................................................................................................................................................... 7

On-chip Current Limit with External Programmability.............................................................................................7

Line Under-Voltage Detection (UV) ........................................................................................................................ 8

Line Overvoltage Shutdown (OV)...........................................................................................................................8

Line Feed Forward with DC

MAX

Reduction ..............................................................................................................8

Remote ON/OFF and Synchronization................................................................................................................... 9

Soft-Start ................................................................................................................................................................9

Shutdown/Auto-Restart ..........................................................................................................................................9

Hysteretic Over-Temperature Protection ................................................................................................................9

Bandgap Reference................................................................................................................................................9

High-Voltage Bias Current Source........................................................................................................................10

Using Feature Pins.................................................................................................................................................... 11

FREQUENCY (F) Pin Operation........................................................................................................................... 11

LINE-SENSE (L) Pin Operation............................................................................................................................ 11

EXTERNAL CURRENT LIMIT (X) Pin Operation ................................................................................................. 11

MULTI-FUNCTION (M) Pin Operation .................................................................................................................. 12

Typical Uses of FREQUENCY (F) Pin ......................................................................................................................15

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins.......................................................16

Typical Uses of MULTI-FUNCTION (M) Pin ............................................................................................................. 19

Application Examples............................................................................................................................................... 21

A High Efficiency, 30 W, Universal Input Power Supply........................................................................................21

A High Efficiency, Enclosed, 70 W, Universal Adapter Supply..............................................................................22

A High Efficiency, 250 W, 250 - 380 VDC Input Power Supply.............................................................................23

Multiple Output, 60 W, 185 - 265 VAC Input Power Supply..................................................................................24

Processor Controlled Supply Turn On/Of f ............................................................................................................ 25

Key Application Considerations ..............................................................................................................................27

TOPSwitch-II vs. TOPSwitch-GX..........................................................................................................................27

TOPSwitch-FX vs. TOPSwitch-GX.......................................................................................................................28

TOPSwitch-GX Design Considerations ................................................................................................................ 29

TOPSwitch-GX Layout Considerations.................................................................................................................31

Quick Design Checklist.........................................................................................................................................31

Design Tools ......................................................................................................................................................... 33

Product Specifications and Test Conditions.......................................................................................................... 34

Typical Performance Characteristics ...................................................................................................................... 41

Part Ordering Information ........................................................................................................................................45

Package Outlines ......................................................................................................................................................45

TOP242-249

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Figure 2a. Functional Block Diagram (Y or R Package).

PI-2641-061200

PI-2639-060600

Figure 2b. Functional Block Diagram (P or G Package).

PI-2631-061200

SHUTDOWN/

AUTO-RESTART

PWM

COMPARATOR

CLOCK

SAW

CONTROLLED

TURN-ON

GATE DRIVER

CURRENT LIMIT

COMPARATOR

INTERNAL UV

COMPARATOR

INTERNAL
SUPPLY

5.8 V

4.8 V

SOURCE (S)

SRQ

D

MAX

STOP

SOFT-

START

­+

CONTROL (C)

MULTI-

FUNCTION (M)

­+

5.8 V

I

FB

R

E

Z

C

V

C

+

-

LEADING

EDGE

BLANKING

÷ 8

1

HYSTERETIC

THERMAL

SHUTDOWN

SHUNT REGULATOR/

ERROR AMPLIFIER

+

-

DRAIN (D)

ON/OFF

SOFT

START

DC

MAX

V

BG

DC

MAX

V

BG

+ V

T

0

OV/UV

V

I (LIMIT)

CURRENT

LIMIT

ADJUST

LINE

SENSE

SOFT START

LIGHT LOAD
FREQUENCY
REDUCTION

STOP LOGIC

OSCILLATOR WITH JITTER

PI-2639-060600

SHUTDOWN/

AUTO-RESTART

PWM

COMPARATOR

CLOCK

SAW

HALF
FREQ.

CONTROLLED

TURN-ON

GATE DRIVER

CURRENT LIMIT

COMPARATOR

INTERNAL UV

COMPARATOR

INTERNAL
SUPPLY

5.8 V

4.8 V

SOURCE (S)

SRQ

D

MAX

STOP

SOFT­START

-

+

CONTROL (C)

LINE-SENSE (L)

EXTERNAL

CURRENT LIMIT (X)

FREQUENCY (F)

­+

5.8 V

1 V

I

FB

R

E

Z

C

V

C

+

-

LEADING

EDGE

BLANKING

÷ 8

1

HYSTERETIC

THERMAL

SHUTDOWN

SHUNT REGULATOR/

ERROR AMPLIFIER

+

-

DRAIN (D)

ON/OFF

SOFT

START

DC

MAX

V

BG

DC

MAX

V

BG

+ V

T

0

OV/UV

V

I (LIMIT)

CURRENT

LIMIT

ADJUST

LINE

SENSE

SOFT START

LIGHT LOAD
FREQUENCY
REDUCTION

STOP LOGIC

OSCILLATOR WITH JITTER

TOP242-249

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Pin Functional Description

DRAIN (D) Pin:

High voltage power MOSFET drain output. The internal start­up bias current is drawn from this pin through a switched high­voltage current source. Internal current limit sense point for
drain current.

CONTROL (C) Pin:

Error amplifier and feedback current input pin for duty cycle
control. Internal shunt regulator connection to provide internal
bias current during normal operation. It is also used as the
connection point for the supply bypass and auto-restart/
compensation capacitor.

LINE-SENSE (L) Pin: (Y or R package only)
Input pin for OV, UV, line feed forward with DC

MAX

reduction,
remote ON/OFF and synchronization. A connection to SOURCE
pin disables all functions on this pin.

EXTERNAL CURRENT LIMIT (X) Pin: (Y or R package only)
Input pin for external current limit adjustment, remote
ON/OFF, and synchronization. A connection to SOURCE pin
disables all functions on this pin.

MULTI-FUNCTION (M) Pin: (P or G package only)
This pin combines the functions of the LINE-SENSE (L) and
EXTERNAL CURRENT LIMIT (X) pins of the Y package into
one pin. Input pin for OV, UV, line feed forward with DC

MAX

reduction, external current limit adjustment, remote ON/OFF
and synchronization. A connection to SOURCE pin disables all
functions on this pin and makes TOPSwitch-GX operate in
simple three terminal mode (like TOPSwitch-II).

FREQUENCY (F) Pin: (Y or R package only)
Input pin for selecting switching frequency: 132 kHz if

Figure 3. Pin Configuration (top view).

PI-2509-040501

DC

Input

Voltage

+

-

DM

S

C

VUV = IUV x R

LS

V

OV = IOV x RLS

For RLS = 2 MΩ
V

UV

= 100 VDC

V

OV =

450 VDC

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

CONTROL

R

LS

2 MΩ

PI-2517-040501

DC

Input

Voltage

+

-

DM

S

C

For R

IL

= 12 kΩ

I

LIMIT

= 69%

CONTROL

R

IL

See fig. 55 for other
resistor values (R

IL

)

For R

IL

= 25 kΩ

I

LIMIT

= 43%

to select different
I

LIMIT

values

X

PI-2629-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

R

IL

R

LS

12 kΩ

2 MΩ

VUV = IUV x R

LS

V

OV = IOV x RLS

For RLS = 2 MΩ

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

For R

IL

= 12 kΩ

I

LIMIT

= 69%

See fig. 55 for other
resistor values (R

IL

)

to select different I

LIMIT

values

V

UV

= 100 VDC

V

OV

= 450 VDC

Figure 4. Y/R Package Line Sense and Externally Set Current

Limit.

Figure 5. P/G Package Line Sense.

Figure 6. P/G Package Externally Set Current Limit.

connected to SOURCE pin and 66 kHz if connected to
CONTROL pin. The switching frequency is internally set for
fixed 132 kHz operation in P and G packages.

SOURCE (S) Pin:

Output MOSFET source connection for high voltage power
return. Primary side control circuit common and reference point.

PI-2724-033001

Tab Internally
Connected to

SOURCE Pin

Y Package (TO-220-7C)

C

D

S
S

S

S

1 C

3 X
2 L

5 F
4 S

7 D

M

P Package (DIP-8B)

G Package (SMD-8B)

R Package

(TO-263-7C)

8

5

7

1

12345 7

CLX SF D

4

2

3

TOP242-249

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TOPSwitch-GX

Family Functional Description

Like TOPSwitch, TOPSwitch-GX is an integrated switched
mode power supply chip that converts a current at the control
input to a duty cycle at the open drain output of a high voltage
power MOSFET. During normal operation the duty cycle of the
power MOSFET decreases linearly with increasing CONTROL
pin current as shown in Figure 7.

In addition to the three terminal TOPSwitch features, such as the
high voltage start-up, the cycle-by-cycle current limiting, loop
compensation circuitry, auto-restart, thermal shutdown, the
TOPSwitch-GX incorporates many additional functions that
reduce system cost, increase power supply performance and
design flexibility. A patented high voltage CMOS technology
allows both the high voltage power MOSFET and all the low
voltage control circuitry to be cost effectively integrated onto a
single monolithic chip.

Three terminals, FREQUENCY, LINE-SENSE, and
EXTERNAL CURRENT LIMIT (available in Y or R package)
or one terminal MULTI-FUNCTION (available in P or G
Package) have been added to implement some of the new
functions. These terminals can be connected to the SOURCE
pin to operate the TOPSwitch-GX in a TOPSwitch-like three
terminal mode. However, even in this three terminal mode, the
TOPSwitch-GX offers many new transparent features that do
not require any external components:

1. A fully integrated 10 ms soft-start limits peak currents and

voltages during start-up and dramatically reduces or
eliminates output overshoot in most applications.

2. DC

MAX

of 78% allows smaller input storage capacitor, lower

input voltage requirement and/or higher power capability.

3. Frequency reduction at light loads lowers the switching

losses and maintains good cross regulation in multiple
output supplies.

4. Higher switching frequency of 132 kHz reduces the

transformer size with no noticeable impact on EMI.

5. Frequency jittering reduces EMI.

6. Hysteretic over-temperature shutdown ensures automatic

recovery from thermal fault. Large hysteresis prevents circuit
board overheating.

7. Packages with omitted pins and lead forming provide large

drain creepage distance.

8. Tighter absolute tolerances and smaller temperature vari-

ations on switching frequency, current limit and PWM gain.

The LINE-SENSE (L) pin is usually used for line sensing by
connecting a resistor from this pin to the rectified DC high
voltage bus to implement line overvoltage (OV), under-voltage
(UV) and line feed forward with DC

MAX

reduction. In this
mode, the value of the resistor determines the OV/UV thresholds
and the DC

MAX

is reduced linearly starting from a line voltage

above the under-voltage threshold. See Table 2 and Figure 11.

The pin can also be used as a remote ON/OFF and a
synchronization input.

The EXTERNAL CURRENT LIMIT (X) pin is usually used to
reduce the current limit externally to a value close to the operating
peak current, by connecting the pin to SOURCE through a
resistor. This pin can also be used as a remote ON/OFF and a
synchronization input in both modes. See Table 2 and Figure 11.

For the P or G packages the LINE-SENSE and EXTERNAL
CURRENT LIMIT pin functions are combined on one MULTI­FUNCTION (M) pin. However, some of the functions become
mutually exclusive as shown in Table 3.

The FREQUENCY (F) pin in the Y or R package sets the
switching frequency to the default value of 132 kHz when
connected to SOURCE pin. A half frequency option of 66 kHz
can be chosen by connecting this pin to CONTROL pin instead.
Leaving this pin open is not recommended.

PI-2633-060500

Duty Cycle (%)

IC (mA)

TOP242/5 1.6 2.0
TOP246/9 2.2 2.6

5.2 6.0

5.8 6.6

I

CD1

I

B

Auto-restart

IL = 125 µA

IL < I

L(DC)

IL = 190 µA

78

10

38

Frequency (kHz)

IC (mA)

30

I

CD1

I

B

Auto-restart

132

Note: For P and G packages IL is replaced with IM.

IL < I

L(DC)

I

L

= 125 µA

Slope = PWM Gain

IL = 190 µA

Figure 7. Relationship of Duty Cycle and Frequency to CONTROL

Pin Current.

TOP242-249

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August 8, 2000

PI-2545-082299

S1 S2 S6 S7 S1 S2 S6 S7S0

S1 S7

S0

S0

5.8 V

4.8 V

S7

0 V

0 V

0 V

V

LINE

V

C

V

DRAIN

V

OUT

Note: S0 through S7 are the output states of the auto-restart counter

2

1

2

3

4

0 V

~

~

~

~

~

~

~

~

~

~

S6 S7

~

~

~

~

~

~

~

~

V

UV

~

~

~

~

~

~

~

~

S2

~

~

CONTROL (C) Pin Operation

The CONTROL pin is a low impedance node that is capable of
receiving a combined supply and feedback current. During
normal operation, a shunt regulator is used to separate the
feedback signal from the supply current. CONTROL pin
voltage VC is the supply voltage for the control circuitry
including the MOSFET gate driver. An external bypass capacitor
closely connected between the CONTROL and SOURCE pins
is required to supply the instantaneous gate drive current. The
total amount of capacitance connected to this pin also sets the
auto-restart timing as well as control loop compensation.

When rectified DC high voltage is applied to the DRAIN pin
during start-up, the MOSFET is initially off, and the CONTROL
pin capacitor is charged through a switched high voltage current
source connected internally between the DRAIN and CONTROL
pins. When the CONTROL pin voltage VC reaches
approximately 5.8 V, the control circuitry is activated and the
soft-start begins. The soft-start circuit gradually increases the
duty cycle of the MOSFET from zero to the maximum value
over approximately 10 ms. If no external feedback/supply
current is fed into the CONTROL pin by the end of the soft-start,
the high voltage current source is turned off and the CONTROL
pin will start discharging in response to the supply current
drawn by the control circuitry. If the power supply is designed
properly, and no fault condition such as open loop or shorted
output exists, the feedback loop will close, providing external
CONTROL pin current, before the CONTROL pin voltage has
had a chance to discharge to the lower threshold voltage of
approximately 4.8 V (internal supply under-voltage lockout
threshold). When the externally fed current charges the
CONTROL pin to the shunt regulator voltage of 5.8 V, current

in excess of the consumption of the chip is shunted to SOURCE
through resistor RE as shown in Figure 2. This current flowing
through RE controls the duty cycle of the power MOSFET to
provide closed loop regulation. The shunt regulator has a finite
low output impedance ZC that sets the gain of the error amplifier
when used in a primary feedback configuration. The dynamic
impedance ZC of the CONTROL pin together with the external
CONTROL pin capacitance sets the dominant pole for the
control loop.

When a fault condition such as an open loop or shorted output
prevents the flow of an external current into the CONTROL pin,
the capacitor on the CONTROL pin discharges towards 4.8 V.
At 4.8 V, auto-restart is activated which turns the output
MOSFET off and puts the control circuitry in a low current
standby mode. The high-voltage current source turns on and
charges the external capacitance again. A hysteretic internal
supply under-voltage comparator keeps VC within a window of
typically 4.8 to 5.8 V by turning the high-voltage current source
on and off as shown in Figure 8. The auto-restart circuit has a
divide-by-8 counter which prevents the output MOSFET from
turning on again until eight discharge/charge cycles have elapsed.
This is accomplished by enabling the output MOSFET only
when the divide-by-8 counter reaches full count (S7). The
counter effectively limits TOPSwitch-GX power dissipation by
reducing the auto-restart duty cycle to typically 4%. Auto­restart mode continues until output voltage regulation is again
achieved through closure of the feedback loop.

Oscillator and Switching Frequency

The internal oscillator linearly charges and discharges an internal
capacitance between two voltage levels to create a sawtooth

Figure 8. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-restart (4) Power Down.

TOP242-249

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Figure 9. Switching Frequency Jitter. (Idealized V

DRAIN

waveform)

waveform for the pulse width modulator. This oscillator sets
the pulse width modulator/current limit latch at the beginning
of each cycle.

The nominal switching frequency of 132 kHz was chosen to
minimize transformer size while keeping the fundamental EMI
frequency below 150 kHz. The FREQUENCY pin (available
only in Y or R package), when shorted to the CONTROL pin,
lowers the switching frequency to 66 kHz (half frequency)
which may be preferable in some cases such as noise sensitive
video applications or a high efficiency standby mode. Otherwise,
the FREQUENCY pin should be connected to the SOURCE pin
for the default 132 kHz.

To further reduce the EMI level, the switching frequency is
jittered (frequency modulated) by approximately ±4 kHz at
250 Hz (typical) rate as shown in Figure 9. Figure 46 shows the
typical improvement of EMI measurements with frequency
jitter.

Pulse Width Modulator and Maximum Duty Cycle

The pulse width modulator implements voltage mode control
by driving the output MOSFET with a duty cycle inversely
proportional to the current into the CONTROL pin that is in
excess of the internal supply current of the chip (see Figure 7).
The excess current is the feedback error signal that appears
across RE (see Figure 2). This signal is filtered by an RC
network with a typical corner frequency of 7 kHz to reduce the
effect of switching noise in the chip supply current generated by
the MOSFET gate driver. The filtered error signal is compared
with the internal oscillator sawtooth waveform to generate the
duty cycle waveform. As the control current increases, the duty
cycle decreases. A clock signal from the oscillator sets a latch
which turns on the output MOSFET. The pulse width modulator
resets the latch, turning off the output MOSFET. Note that a
minimum current must be driven into the CONTROL pin
before the duty cycle begins to change.

The maximum duty cycle, DC

MAX,

is set at a default maximum
value of 78% (typical). However, by connecting the LINE­SENSE or MULTI-FUNCTION pin (depending on the package)
to the rectified DC high voltage bus through a resistor with
appropriate value, the maximum duty cycle can be made to
decrease from 78% to 38% (typical) as shown in Figure 11 when
input line voltage increases (see line feed forward with DC

MAX

reduction).

Light Load Frequency Reduction

The pulse width modulator duty cycle reduces as the load at the
power supply output decreases. This reduction in duty cycle is
proportional to the current flowing into the CONTROL pin. As
the CONTROL pin current increases, the duty cycle decreases
linearly towards a duty cycle of 10%. Below 10% duty cycle, to
maintain high efficiency at light loads, the frequency is also
reduced linearly until a minimum frequency is reached at a duty

cycle of 0% (refer to Figure 7). The minimum frequency is
typically 30 kHz and 15 kHz for 132 kHz and 66 kHz operation,
respectively.

This feature allows a power supply to operate at lower frequency
at light loads thus lowering the switching losses while
maintaining good cross regulation performance and low output
ripple.

Error Amplifier

The shunt regulator can also perform the function of an error
amplifier in primary side feedback applications. The shunt
regulator voltage is accurately derived from a temperature­compensated bandgap reference. The gain of the error amplifier
is set by the CONTROL pin dynamic impedance. The
CONTROL pin clamps external circuit signals to the V

C

voltage level. The CONTROL pin current in excess of the
supply current is separated by the shunt regulator and flows
through RE as a voltage error signal.

On-chip Current Limit with External Programmability

The cycle-by-cycle peak drain current limit circuit uses the
output MOSFET ON-resistance as a sense resistor. A current
limit comparator compares the output MOSFET on-state drain
to source voltage, V

DS(ON)

with a threshold voltage. High drain

current causes V

DS(ON)

to exceed the threshold voltage and turns
the output MOSFET off until the start of the next clock cycle.
The current limit comparator threshold voltage is temperature
compensated to minimize the variation of the current limit due
to temperature related changes in R

DS(ON)

of the output MOSFET.
The default current limit of TOPSwitch-GX is preset internally.
However, with a resistor connected between EXTERNAL
CURRENT LIMIT (X) pin (Y or R package) or MULTI­FUNCTION (M) pin (P or G package) and SOURCE pin,
current limit can be programmed externally to a lower level
between 30% and 100% of the default current limit. Please
refer to the graphs in the typical performance characteristics
section for the selection of the resistor value. By setting current
limit low, a larger TOPSwitch-GX than necessary for the power
required can be used to take advantage of the lower R

DS(ON)

for

higher efficiency/smaller heat sinking requirements. With a

PI-2550-092499

128 kHz

4 ms

Time

Switching

Frequency

V

DRAIN

136 kHz

TOP242-249

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Figure 10. Synchronization Timing Diagram.

PI-2637-060600

Oscillator

(SAW)

D

MAX

Enable from

X, L or M Pin (STOP)

Time

second resistor connected between the EXTERNAL CURRENT
LIMIT (X) pin (Y or R package) or MULTI-FUNCTION (M)
pin (P or G package) and the rectified DC high voltage bus, the
current limit is reduced with increasing line voltage, allowing
a true power limiting operation against line variation to be
implemented. When using an RCD clamp, this power limiting
technique reduces maximum clamp voltage at high line. This
allows for higher reflected voltage designs as well as reducing
clamp dissipation.

The leading edge blanking circuit inhibits the current limit
comparator for a short time after the output MOSFET is turned
on. The leading edge blanking time has been set so that, if a
power supply is designed properly, current spikes caused by
primary-side capacitances and secondary-side rectifier reverse
recovery time should not cause premature termination of the
switching pulse.

The current limit is lower for a short period after the leading
edge blanking time as shown in Figure 52. This is due to
dynamic characteristics of the MOSFET. To avoid triggering
the current limit in normal operation, the drain current waveform
should stay within the envelope shown.

Line Under-Voltage Detection (UV)

At power up, UV keeps TOPSwitch-GX off until the input line
voltage reaches the under voltage threshold. At power down,
UV prevents auto-restart attempts after the output goes out of
regulation. This eliminates power down glitches caused by the
slow discharge of large input storage capacitor present in
applications such as standby supplies. A single resistor connected
from the LINE-SENSE pin (Y or R package) or MULTI­FUNCTION pin (P or G package) to the rectified DC high
voltage bus sets UV threshold during power up. Once the power
supply is successfully turned on, the UV threshold is lowered to

40% of the initial UV threshold to allow extended input voltage
operating range (UV low threshold). If the UV low threshold
is reached during operation without the power supply losing
regulation the device will turn off and stay off until UV (high
threshold) has been reached again. If the power supply loses
regulation before reaching the UV low threshold, the device
will enter auto-restart. At the end of each auto-restart cycle (S7),
the UV comparator is enabled. If the UV high threshold is not
exceeded the MOSFET will be disabled during the next cycle (see
figure 8). The UV feature can be disabled independent of OV
feature as shown in Figure 19 and 23.

Line Overvoltage Shutdown (OV)

The same resistor used for UV also sets an overvoltage threshold
which, once exceeded, will force TOPSwitch-GX output into
off-state. The ratio of OV and UV thresholds is preset at 4.5 as
can be seen in Figure 11. When the MOSFET is off, the rectified
DC high voltage surge capability is increased to the voltage
rating of the MOSFET (700 V), due to the absence of the
reflected voltage and leakage spikes on the drain. A small
amount of hysteresis is provided on the OV threshold to prevent
noise triggering. The OV feature can be disabled independent
of the UV feature as shown in Figure 18 and 32.

Line Feed Forward with DC

MAX

Reduction

The same resistor used for UV and OV also implements line
voltage feed forward which minimizes output line ripple and
reduces power supply output sensitivity to line transients. This
feed forward operation is illustrated in Figure 7 by the different
values of IL (Y or R package) or IM (P or G Package). Note that
for the same CONTROL pin current, higher line voltage results
in smaller operating duty cycle. As an added feature, the
maximum duty cycle DC

MAX

is also reduced from 78% (typical)
at a voltage slightly higher than the UV threshold to 38%
(typical) at the OV threshold (see Figures 7, 11). Limiting

TOP242-249

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DC

MAX

at higher line voltages helps prevent transformer
saturation due to large load transients in forward converter
applications. DC

MAX

of 38% at the OV threshold was chosen to
ensure that the power capability of the TOPSwitch-GX is not
restricted by this feature under normal operation.

Remote ON/OFF and Synchronization

TOPSwitch-GX can be turned on or off by controlling the
current into the LINE-SENSE pin or out from the EXTERNAL
CURRENT LIMIT pin (Y or R package) and into or out from
the MULTI-FUNCTION pin (P or G package) (see Figure 11).
In addition, the LINE-SENSE pin has a 1 V threshold comparator
connected at its input. This voltage threshold can also be used
to perform remote ON/OFF control. This allows easy
implementation of remote ON/OFF control of TOPSwitch-GX
in several different ways. A transistor or an optocoupler output
connected between the EXTERNAL CURRENT LIMIT or
LINE-SENSE pins (Y or R package) or the MULTI-FUNCTION
pin (P or G package) and the SOURCE pin implements this
function with “active-on” (Figure 22, 29 and 36) while a
transistor or an optocoupler output connected between the
LINE-SENSE pin (Y or R package) or the MULTI-FUNCTION
(P or G package) pin and the CONTROL pin implements the
function with “active-off” (Figure 23 and 37).

When a signal is received at the LINE-SENSE pin or the
EXTERNAL CURRENT LIMIT pin (Y or R package) or the
MULTI-FUNCTION pin (P or G package) to disable the output
through any of the pin functions such as OV, UV and remote
ON/OFF, TOPSwitch-GX always completes its current switching
cycle, as illustrated in Figure 10, before the output is forced off.
The internal oscillator is stopped slightly before the end of the
current cycle and stays there as long as the disable signal exists.
When the signal at the above pins changes state from disable to
enable, the internal oscillator starts the next switching cycle.
This approach allows the use of this pin to synchronize
TOPSwitch-GX to any external signal with a frequency lower
than its internal switching frequency.

As seen above, the remote ON/OFF feature allows the
TOPSwitch-GX to be turned on and off instantly, on a cycle-by­cycle basis, with very little delay. However, remote ON/OFF
can also be used as a standby or power switch to turn off the
TOPSwitch-GX and keep it in a very low power consumption
state for indefinitely long periods. If the TOPSwitch-GX is held
in remote off state for long enough time to allow the CONTROL
pin to dishcharge to the internal supply under-voltage threshold
of 4.8 V (approximately 32 ms for a 47 µF CONTROL pin
capacitance), the CONTROL pin goes into the hysteretic mode
of regulation. In this mode, the CONTROL pin goes through
alternate charge and discharge cycles between 4.8 V and 5.8 V
(see CONTROL pin operation section above) and runs entirely
off the high voltage DC input, but with very low power
consumption (160 mW typical at 230 VAC with M or X pins

open). When the TOPSwitch-GX is remotely turned on after
entering this mode, it will initiate a normal start-up sequence
with soft-start the next time the CONTROL pin reaches 5.8 V.
In the worst case, the delay from remote on to start-up can be
equal to the full discharge/charge cycle time of the CONTROL
pin, which is approximately 125 ms for a 47 µF CONTROL pin
capacitor. This reduced consumption remote off mode can
eliminate expensive and unreliable in-line mechanical switches.
It also allows for microprocessor controlled turn-on and turn­off sequences that may be required in certain applications such
as inkjet and laser printers.

Soft-Start

Two on-chip soft-start functions are activated at start-up with a
duration of 10 ms (typical). Maximum duty cycle starts from
0% and linearly increases to the default maximum of 78% at the
end of the 10 ms duration and the current limit starts from about
85% and linearly increases to 100% at the end of the 10ms
duration. In addition to start-up, soft-start is also activated at
each restart attempt during auto-restart and when restarting
after being in hysteretic regulation of CONTROL pin voltage
(V

C

), due to remote off or thermal shutdown conditions. This
effectively minimizes current and voltage stresses on the output
MOSFET, the clamp circuit and the output rectifier during start­up. This feature also helps minimize output overshoot and
prevents saturation of the transformer during start-up.

Shutdown/Auto-Restart

To minimize TOPSwitch-GX power dissipation under fault
conditions, the shutdown/auto-restart circuit turns the power
supply on and off at an auto-restart duty cycle of typically 4%
if an out of regulation condition persists. Loss of regulation
interrupts the external current into the CONTROL pin. V

C

regulation changes from shunt mode to the hysteretic auto­restart mode as described in CONTROL pin operation section.
When the fault condition is removed, the power supply output
becomes regulated, VC regulation returns to shunt mode, and
normal operation of the power supply resumes.

Hysteretic Over-Temperature Protection

Temperature protection is provided by a precision analog
circuit that turns the output MOSFET off when the junction
temperature exceeds the thermal shutdown temperature
(140 °C typical). When the junction temperature cools to below
the hysteretic temperature, normal operation resumes providing
automatic recovery. A large hysteresis of 70 °C (typical) is
provided to prevent overheating of the PC board due to a
continuous fault condition. VC is regulated in hysteretic mode
and a 4.8 V to 5.8 V (typical) sawtooth waveform is present on
the CONTROL pin while in thermal shutdown.

Bandgap Reference

All critical TOPSwitch-GX internal voltages are derived from a
temperature-compensated bandgap reference. This reference is

TOP242-249

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also used to generate a temperature-compensated current
reference which is trimmed to accurately set the switching
frequency, MOSFET gate drive current, current limit, and the
line OV/UV thresholds. TOPSwitch-GX has improved circuitry
to maintain all of the above critical parameters within very tight
absolute and temperature tolerances.

High-Voltage Bias Current Source

This current source biases TOPSwitch-GX from the DRAIN pin
and charges the CONTROL pin external capacitance during
start-up or hysteretic operation. Hysteretic operation occurs
during auto-restart, remote off and over-temperature shutdown.
In this mode of operation, the current source is switched on and
off with an effective duty cycle of approximately 35%. This
duty cycle is determined by the ratio of CONTROL pin charge
(I

C

) and discharge currents (I

CD1

and I

CD2

). This current source
is turned off during normal operation when the output MOSFET
is switching. The effect of the current source switching will be
seen on the DRAIN voltage waveform as small disturbances
and is normal.

TOP242-249

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Refer to Table 2 for possible combinations of the functions with
example circuits shown in Figure 16 through Figure 40. A
description of specific functions in terms of the LINE-SENSE
pin I/V characteristic is shown in Figure 11 (right hand side).
The horizontal axis represents LINE-SENSE pin current with
positive polarity indicating currents flowing into the pin. The
meaning of the vertical axes varies with functions. For those
that control the on/off states of the output such as UV, OV and
remote ON/OFF, the vertical axis represents the enable/disable
states of the output. UV triggers at IUV (+50 µA typical with
30 µA hysteresis) and OV triggers at IOV (+225 µA typical with
8 µA hysteresis). Between the UV and OV thresholds, the
output is enabled. For line feed forward with DC

MAX

reduction,

the vertical axis represents the magnitude of the DC

MAX

. Line

feed forward with DC

MAX

reduction lowers maximum duty cycle

from 78% at I

L(DC)

(+60 µA typical) to 38% at IOV (+225 µA).

EXTERNAL CURRENT LIMIT (X) Pin Operation
(Y and R Packages)

When current is drawn out of the EXTERNAL CURRENT
LIMIT pin, it works as a voltage source of approximately 1.3
V up to a maximum current of –240 µA (typical). At –240 µA,
it turns into a constant current source (refer to Figure 12a).

There are two functions available through the use of the
EXTERNAL CURRENT LIMIT pin: external current limit
and remote ON/OFF. Connecting the EXTERNAL CURRENT
LIMIT pin and SOURCE pin disables the two functions. In
high efficiency applications this pin can be used to reduce the
current limit externally to a value close to the operating peak
current, by connecting the pin to the SOURCE pin through a
resistor. The pin can also be used as a remote on/off. Table 2
shows several possible combinations using this pin. See Figure

FREQUENCY (F) Pin Operation

The FREQUENCY pin is a digital input pin available in the
Y or R package only. Shorting the FREQUENCY pin to
SOURCE pin selects the nominal switching frequency of
132 kHz (Figure 13) which is suited for most applications. For
other cases that may benefit from lower switching frequency
such as noise sensitive video applications, a 66 kHz switching
frequency (half frequency) can be selected by shorting the
FREQUENCY pin to the CONTROL pin (Figure 14). In
addition, an example circuit shown in Figure 15 may be used to
lower the switching frequency from 132 kHz in normal
operation to 66 kHz in standby mode for very low standby
power consumption.

LINE-SENSE (L) Pin Operation (Y and R Packages)

When current is fed into the LINE-SENSE pin, it works as a
voltage source of approximately 2.6 V up to a maximum
current of +400 µA (typical). At +400 µA, this pin turns into
a constant current sink. Refer to Figure 12a. In addition, a
comparator with a threshold of 1 V is connected at the pin and
is used to detect when the pin is shorted to the SOURCE pin.

There are a total of four functions available through the use of
the LINE-SENSE pin: OV, UV, line feed forward with DC

MAX

reduction, and remote ON/OFF. Connecting the LINE-SENSE
pin to the SOURCE pin disables all four functions. The LINE­SENSE pin is typically used for line sensing by connecting a
resistor from this pin to the rectified DC high voltage bus to
implement OV, UV and DC

MAX

reduction with line voltage. In
this mode, the value of the resistor determines the line OV/UV
thresholds, and the DC

MAX

is reduced linearly with rectified DC
high voltage starting from just above the UV threshold. The pin
can also be used as a remote on/off and a synchronization input.

Using Feature Pins

✔

✔✔ ✔ ✔ ✔

✔✔ ✔✔✔

✔✔✔✔

✔

✔✔ ✔✔ ✔✔

✔✔✔✔✔✔ ✔

16 17 18 19 20 21 22 23 24 25 26 27 28 29

Table 2. Typical LINE-SENSE and EXTERNAL CURRENT LIMIT Pin Configurations.

LINE-SENSE AND EXTERNAL CURRENT LIMIT PIN TABLE*

*This table is only a partial list of many LINE-SENSE and EXTERNAL CURRENT LIMIT pin configurations that are possible.

▲

Figure Number
Three Terminal Operation

Under-Voltage
Overvoltage
Line Feed Forward (DC

MAX

)
Overload Power Limiting
External Current Limit
Remote ON/OFF

TOP242-249

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✔

✔✔ ✔

✔✔ ✔

✔✔

✔

✔✔ ✔✔

✔✔✔✔✔

Table 3. Typical MULTI-FUNCTION Pin Configurations.

MULTI-FUNCTION PIN TABLE*

30 31 32 33 34 35 36 37 38 39 40

*This table is only a partial list of many MULTI-FUNCTION pin configurations that are possible.

▲

Figure Number
Three Terminal Operation

Under-Voltage
Overvoltage
Line Feed Forward (DC

MAX

)
Overload Power Limiting
External Current Limit
Remote ON/OFF

11 for a description of the functions where the horizontal axis
(left hand side) represents the EXTERNAL CURRENT LIMIT
pin current. The meaning of the vertical axes varies with
function. For those that control the on/off states of the output
such as remote ON/OFF, the vertical axis represents the enable/
disable states of the output. For external current limit, the
vertical axis represents the magnitude of the I

LIMIT

. Please see
graphs in the typical performance characteristics section for the
current limit programming range and the selection of appropriate
resistor value.

MULTI-FUNCTION (M) Pin Operation (P and G Packages)

The LINE-SENSE and EXTERNAL CURRENT LIMIT pin
functions are combined to a single MULTI-FUNCTION pin for
P and G packages. The comparator with a 1 V threshold at the
LINE-SENSE pin is removed in this case as shown in Figure 2b.
All of the other functions are kept intact. However, since some
of the functions require opposite polarity of input current
(MULTI-FUNCTION pin), they are mutually exclusive. For
example, line sensing features cannot be used simultaneously
with external current limit setting. When current is fed into the
MULTI-FUNCTION pin, it works as a voltage source of
approximately 2.6 V up to a maximum current of +400 µA
(typical). At +400 µA, this pin turns into a constant current sink.
When current is drawn out of the MULTI-FUNCTION pin, it
works as a voltage source of approximately 1.3 V up to a
maximum current of –240 µA (typical). At –240 µA, it turns
into a constant current source. Refer to Figure 12b.

There are a total of five functions available through the use of
the MULTI-FUNCTION pin: OV, UV, line feed forward with
DC

MAX

reduction, external current limit and remote ON/OFF. A
short circuit between the MULTI-FUNCTION pin and
SOURCE pin disables all five functions and forces

TOPSwitch-GX to operate in a simple three terminal mode like
TOPSwitch-II. The MULTI-FUNCTION pin is typically used

for line sensing by connecting a resistor from this pin to the
rectified DC high voltage bus to implement OV, UV and DC

MAX

reduction with line voltage. In this mode, the value of the
resistor determines the line OV/UV thresholds, and the DC

MAX

is reduced linearly with rectified DC high voltage starting from
just above the UV threshold. In high efficiency applications
this pin can be used in the external current limit mode instead,
to reduce the current limit externally to a value close to the
operating peak current, by connecting the pin to the SOURCE
pin through a resistor. The same pin can also be used as a remote
on/off and a synchronization input in both modes. Please refer
to Table 3 for possible combinations of the functions with
example circuits shown in Figure 30 through Figure 40. A
description of specific functions in terms of the MULTI­FUNCTION pin I/V characteristic is shown in Figure 11. The
horizontal axis represents MULTI-FUNCTION pin current
with positive polarity indicating currents flowing into the pin.
The meaning of the vertical axes varies with functions. For
those that control the on/off states of the output such as UV, OV
and remote ON/OFF, the vertical axis represents the enable/
disable states of the output. UV triggers at IUV (+50 µA typical)
and OV triggers at IOV (+225 µA typical with 30 µA hysteresis).
Between the UV and OV thresholds, the output is enabled. For
external current limit and line feed forward with DC

MAX

reduction, the vertical axis represents the magnitude of the I

LIMIT

and DC

MAX

. Line feed forward with DC

MAX

reduction lowers

maximum duty cycle from 78% at I

M(DC)

(+60 µA typical) to 38%

at IOV (+225 µA). External current limit is available only with
negative MULTI-FUNCTION pin current. Please see graphs in
the typical performance characteristics section for the current
limit programming range and the selection of appropriate resistor
value.

TOP242-249

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Figure 11. MULTI-FUNCTION (P or G package), LINE-SENSE, and EXTERNAL CURRENT LIMIT (Y or R package) Pin Characteristics.

-250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400

PI-2636-040501

Output
MOSFET
Switching

(Enabled)

(Disabled)

I

LIMIT

(Default)

DC

MAX

(78.5%)

Current

Limit

M Pin

L PinX Pin

Maximum

Duty Cycle

V

BG

-22 µA

-27 µA
V

BG

+ V

TP

I

I

I

I

I

UV

I

REM(N)

I

OV

Pin Voltage

Note: This figure provides idealized functional characteristics with typical performance values. Please refer to the parametric
table and typical performance characteristics sections of the data sheet for measured data.

X and L Pins (Y or R Package) and M Pin (P or G Package) Current (µA)

Disabled when supply
output goes out of
regulation

TOP242-249

14

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August 8, 2000

Figure 12a. LINE-SENSE (L), and EXTERNAL CURRENT LIMIT (X) Pin Input Simplified Schematic.

Figure 12b. MULTI-FUNCTION (M) Pin Input Simplified Schematic.

VBG + V

T

1 V

V

BG

240 µA

400 µA

CONTROL Pin

Y and R Package

(Voltage Sense)

(Positive Current Sense - Under-Voltage,

Overvoltage, ON/OFF Maximum Duty

Cycle Reduction)

(Negative Current Sense - ON/OFF,

Current Limit Adjustment)

PI-2634-033001

TOPSwitch-GX

LINE-SENSE (L)

EXTERNAL CURRENT LIMIT (X)

VBG + V

T

V

BG

240 µA

400 µA

CONTROL Pin

MULTI-FUNCTION (M)

(Positive Current Sense - Under-Voltage,

Overvoltage, Maximum Duty

Cycle Reduction)

(Negative Current Sense - ON/OFF,

Current Limit Adjustment)

PI-2548-092399

TOPSwitch-GX

P and G Package

TOP242-249

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Figure 15. Half Frequency Standby Mode (For High Standby

Efficiency).

Figure 13. Full Frequency Operation (132 kHz). Figure 14. Half Frequency Operation (66 kHz).

Typical Uses of FREQUENCY (F) Pin

PI-2654-071700

DC

Input

Voltage

+

-

D

S

C

CONTROL

F

PI-2655-071700

DC

Input

Voltage

+

-

D

S

C

CONTROL

F

PI-2656-040501

DC

Input

Voltage

+

-

D

S

C

STANDBY

QS can be an optocoupler output.

CONTROL

F

20 kΩ

R

HF

1 nF

Q

S

47 kΩ

TOP242-249

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August 8, 2000

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins

XF

PI-2617-050100

DC

Input

Voltage

+

-

D

CS D

S

C

CONTROL

L

CLXS F D

PI-2618-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

2MΩR

LS

VUV = IUV x R

LS

V

OV = IOV x RLS

For RLS = 2 MΩ
V

UV

= 100 VDC

V

OV =

450 VDC

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

PI-2510-040501

DC

Input

Voltage

+

-

DM

S

C

VUV = RLS x I

UV

For Value Shown
V

UV

= 100 VDC

R

LS

6.2 V

2 MΩ

22 kΩ

CONTROL

PI-2620-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

2 MΩ

30 kΩ

R

LS

1N4148

V

OV

= I

OV x RLS

For Values Shown
V

OV

= 450 VDC

X

PI-2623-040501

DC

Input

Voltage

+

-

D

S

C

R

IL

For R

IL

= 12 kΩ

I

LIMIT

= 69%

See fig. 55 for other
resistor values (R

IL

)

For R

IL

= 25 kΩ

I

LIMIT

= 43%

CONTROL

X

PI-2624-040501

DC

Input

Voltage

+

-

D

S

C

2.5 MΩR

LS

6 kΩ

R

IL

100% @ 100 VDC
63% @ 300 VDC

I

LIMIT

=

I

LIMIT

=

CONTROL

Figure 16. Three Terminal Operation (LINE-SENSE and

EXTERNAL CURRENT LIMIT Features Disabled.
FREQUENCY Pin can be tied to SOURCE or
CONTROL Pin).

Figure 17. Line-Sensing for Under-Voltage, Overvoltage and

Line Feed Forward.

Figure 18. Line-Sensing for Under-Voltage Only (Overvoltage

Disabled).

Figure 19. Line-Sensing for Overvoltage Only (Under-Voltage

Disabled). Maximum Duty Cycle will be reduced at
Low Line.

Figure 20. Externally Set Current Limit.

Figure 21. Current Limit Reduction with Line Voltage.

TOP242-249

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T ypical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)

Figure 22. Active-on (Fail Safe) Remote ON/OFF.

X

PI-2625-040501

DC

Input

Voltage

+

-

D

S

C

ON/OFF

47 kΩ

QR can be an optocoupler
output or can be replaced by
a manual switch.

Q

R

CONTROL

X

ON/OFF

47 kΩ

PI-2626-040501

DC

Input

Voltage

+

-

D

S

C

R

IL

Q

R

12 kΩ

For R

IL

=

I

LIMIT

= 69 %

25 kΩ

For R

IL

=

I

LIMIT

= 43 %

Q

R

can be an optocoupler
output or can be replaced
by a manual switch.

CONTROL

PI-2627-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

47 kΩ

Q

R

R

MC

45 kΩ

QR can be an
optocoupler output
or can be replaced
by a manual switch.

ON/OFF

X

R

IL

PI-2622-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

47 kΩ

2 MΩ

Q

R

R

LS

ON/OFF

For RLS = 2 MΩ
V

UV

= 100 VDC

V

OV

= 450 VDC

Q

R

can be an optocoupler
output or can be replaced
by a manual switch.

X

ON/OFF

47 kΩ

PI-2628-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

R

IL

R

LS

Q

R

2 MΩ

VUV = IUV x R

LS

V

OV = IOV x RLS

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

12 kΩ

For R

IL

=

I

LIMIT

= 69 %

Q

R

can be an optocoupler
output or can be replaced
by a manual switch.

Figure 23. Active-off Remote ON/OFF. Maximum Duty Cycle will

be reduced.

Figure 24. Active-on Remote ON/OFF with Externally Set Current

Limit.

Figure 25. Active-off Remote ON/OFF with Externally Set Current

Limit.

Figure 26. Active-off Remote ON/OFF with LINE-SENSE.

Figure 27. Active-on Remote ON/OFF with LINE-SENSE and

EXTERNAL CURRENT LIMIT.

PI-2621-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

47 kΩ

Q

R

R

MC

45 kΩ

QR can be an
optocoupler output or
can be replaced
by a manual switch.

ON/OFF

TOP242-249

18

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August 8, 2000

T ypical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)

Figure 28. Line-Sensing and Externally Set Current Limit.

PI-2640-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

ON/OFF

47 kΩ

QR can be an optocoupler
output or can be replaced by
a manual switch.

300 kΩ

Q

R

Figure 29. Active-on Remote ON/OFF.

X

PI-2629-040501

DC

Input

Voltage

+

-

D

S

C

CONTROL

L

R

IL

R

LS

12 kΩ

2 MΩ

VUV = IUV x R

LS

V

OV = IOV x RLS

For RLS = 2 MΩ

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

For R

IL

= 12 kΩ

I

LIMIT

= 69%

See fig. 55 for other
resistor values (R

IL

)

to select different I

LIMIT

values

V

UV

= 100 VDC

V

OV

= 450 VDC

TOP242-249

19

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Figure 32. Line Sensing for Under-Voltage Only (Overvoltage

Disabled).

PI-2510-040501

DC

Input

Voltage

+

-

DM

S

C

VUV = RLS x I

UV

For Value Shown
V

UV

= 100 VDC

R

LS

6.2 V

2 MΩ

22 kΩ

CONTROL

Figure 33. Line Sensing for Overvoltage Only (Under-Voltage

Disabled). Maximum Duty Cycle will be reduced at
Low Line.

Figure 34. Externally Set Current Limit.

PI-2517-040501

DC

Input

Voltage

+

-

DM

S

C

For R

IL

= 12 kΩ

I

LIMIT

= 69%

CONTROL

R

IL

See fig. 55 for other
resistor values (R

IL

)

For R

IL

= 25 kΩ

I

LIMIT

= 43%

to select different
I

LIMIT

values

PI-2516-040501

DC

Input

Voltage

+

-

DM

S

C

V

OV

= I

OV x RLS

For Values Shown
V

OV

= 450 VDC

CONTROL

R

LS

1N4148

2 MΩ

30 kΩ

Figure 30. Three Terminal Operation (MULTI-FUNCTION

Features Disabled).

Figure 31. Line Sensing for Undervoltage, Over-Voltage and

Line Feed Forward.

PI-2508-081199

DC

Input

Voltage

+

-

D

S

C

CONTROL

M

C

DS

CD S

S

SS

M

PI-2509-040501

DC

Input

Voltage

+

-

DM

S

C

VUV = IUV x R

LS

V

OV = IOV x RLS

For RLS = 2 MΩ
V

UV

= 100 VDC

V

OV =

450 VDC

DC

MAX

@100 VDC = 78%

DC

MAX

@375 VDC = 38%

CONTROL

R

LS

2 MΩ

Typical Uses of MULTI-FUNCTION (M) Pin

Figure 35. Current Limit Reduction with Line Voltage.

PI-2518-040501

DC

Input

Voltage

+

-

DM

S

C

CONTROL

R

IL

RLS2.5 MΩ

6 kΩ

100% @ 100 VDC
63% @ 300 VDC

I

LIMIT

=

I

LIMIT

=

TOP242-249

20

E
7/01

August 8, 2000

PI-2522-040501

DC

Input

Voltage

+

-

D

S

C

R

MC

45 kΩ

M

CONTROL

Q

R

QR can be an optocoupler
output or can be replaced
by a manual switch.

ON/OFF

47 kΩ

Figure 37. Active-off Remote ON/OFF. Maximum Duty Cycle will

be Reduced.

Figure 36. Active-on (Fail Safe) Remote ON/OFF.

PI-2519-040501

DC

Input

Voltage

+

-

D

S

C

Q

R

ON/OFF

M

CONTROL

QR can be an optocoupler
output or can be replaced by
a manual switch.

47 kΩ

PI-2523-040501

DC

Input

Voltage

+

-

D

S

C

R

LS

M

For RLS = 2 MΩ
V

UV

= 100 VDC

V

OV

= 450 VDC

CONTROL

Q

R

2 MΩ

QR can be an optocoupler
output or can be replaced
by a manual switch.

ON/OFF

47 kΩ

Figure 40. Active-off Remote ON/OFF with LINE-SENSE.

Figure 39. Active-off Remote ON/OFF with Externally Set

Current Limit.

PI-2521-040501

DC

Input

Voltage

+

-

D

S

C

R

IL

R

MC

24 kΩ

12 kΩ

M

CONTROL

Q

R

2R

IL

R

MC

=

Q

R

can be an optocoupler
output or can be replaced
by a manual switch.

ON/OFF

47 kΩ

Figure 38. Active-on Remote ON/OFF with Externally Set

Current Limit.

PI-2520-040501

DC

Input

Voltage

+

-

D

S

C

Q

R

R

IL

M

CONTROL

12 kΩ

For R

IL

=

I

LIMIT

= 69 %

Q

R

can be an optocoupler
output or can be replaced
by a manual switch.

ON/OFF

47 kΩ

25 kΩ

For R

IL

=

I

LIMIT

= 43 %

Typical Uses of MULTI-FUNCTION (M) Pin (cont.)

TOP242-249

21

August 8, 2000

E

7/01

Figure 41. 30 W Power Supply using External Current Limit Programming and Line Sensing for UV and OV.

Application Examples

A High Efficiency, 30 W, Universal Input Power Supply

The circuit shown in Figure 41 takes advantage of several of the
TOPSwitch-GX features to reduce system cost and power
supply size and to improve efficiency. This design delivers
30 W at 12 V, from an 85 to 265 VAC input, at an ambient of
50 °C, in an open frame configuration. A nominal efficiency of
80% at full load is achieved using TOP244Y.

The current limit is externally set by resistors R1 and R2 to a
value just above the low line operating peak DRAIN current of
approximately 70% of the default current limit. This allows use
of a smaller transformer core size and/or higher transformer
primary inductance for a given output power, reducing
TOPSwitch-GX power dissipation, while at the same time
avoiding transformer core saturation during startup and output
transient conditions. The resistors R1 & R2 provide a signal
that reduces the current limit with increasing line voltage,
which in turn limits the maximum overload power at high input
line voltage. This function in combination with the built-in
soft-start feature of TOPSwitch-GX, allows the use of a low cost
RCD clamp (R3, C3 and D1) with a higher reflected voltage, by
safely limiting the TOPSwitch-GX drain voltage, with adequate

margin under worst case conditions. Resistor R4 provides line
sensing, setting UV at 100 VDC and OV at 450 VDC. The
extended maximum duty cycle feature of TOPSwitch-GX
(guaranteed minimum value of 75% vs. 64% for TOPSwitch-II)
allows the use of a smaller input capacitor (C1). The extended
maximum duty cycle and the higher reflected voltage possible
with the RCD clamp also permit the use of a higher primary to
secondary turns ratio for T1 which reduces the peak reverse
voltage experienced by the secondary rectifier D8. As a result
a 60 V Schottky rectifier can be used for up to 15 V outputs,
which greatly improves power supply efficiency. The frequency
reduction feature of the TOPSwitch-GX eliminates the need for
any dummy loading for regulation at no load and reduces the no
load/standby consumption of the power supply. Frequency
jitter provides improved margin for conducted EMI meeting the
CISPR 22 (FCC B) specification.

Output regulation is achieved by using a simple Zener sense
circuit for low cost. The output voltage is determined by the
Zener diode (VR2) voltage and the voltage drops across the
optocoupler (U2) LED and resistor R6. Resistor R8 provides
bias current to Zener VR2 for typical regulation of ±5% at the
12 V output level, over line and load and component variations.

12 V
@ 2.5 A

D2

1N4148

T1

C5

47 µF

10 V

U2

LTV817A

VR2
1N5240C
10 V, 2%

R6

150 Ω

R15

150 Ω

C14
1 nF

D1

UF4005

R3

68 kΩ

2 W

C3

4.7 nF
1 kV

CY1

2.2 nF

U1

TOP244Y

DL

SXF

C

R8

150 Ω

C1
68 µF
400 V

C6

0.1 µF

D8

MBR1060

C10

560 µF

35 V

C12

220 µF

35 V

C11

560 µF

35 V

RTN

R5

6.8 Ω

R1

4.7 MΩ
1/2 W

R4

2 MΩ

1/2 W

R2

9.09 kΩ

PI-2657-040501

L3

3.3 µH

BR1

600 V

2A

F1

3.15 A

J1

L1

20 mH

L

N

CX1

100 nF

250 VAC

CONTROL

CONTROL

TOPSwitch-GX

PERFORMANCE SUMMARY
Output Power: 30 W

Regulation: ± 4%
Efficiency: ≥ 79%
Ripple: ≤ 50 mV pk-pk

TOP242-249

22

E
7/01

August 8, 2000

A High Efficiency, Enclosed, 70 W, Universal Adapter Supply

The circuit shown in figure 42 takes advantage of several of the
TOPSwitch-GX features to reduce cost, power supply size and
increase efficiency. This design delivers 70 W at 19 V, from an
85 to 265 VAC input, at an ambient of 40 °C, in a small sealed
adapter case (4” x 2.15” x 1”). Full load efficiency is 85% at 85
VAC rising to 90% at 230 VAC input.

Due to the thermal environment of a sealed adapter a TOP249Y
is used to minimize device dissipation. Resistors R9 and R10
externally program the current limit level to just above the
operating peak DRAIN current at full load and low line. This
allows the use of a smaller transformer core size without saturation
during startup or output load transients. Resistors R9 and R10 also
reduce the current limit with increasing line voltage, limiting the
maximum overload power at high input line voltage, removing the
need for any protection circuitry on the secondary. Resistor R11
implements an under voltage and over voltage sense as well as
providing line feed forward for reduced output line frequency
ripple. With resistor R11 set at 2 MΩ the power supply does not
start operating until the DC rail voltage reaches 100 VDC. On
removal of the AC input the UV sense prevents the output
glitching as C1 discharges, turning off the TOPSwitch-GX when
the output regulation is lost or when the input voltage falls to below
40 V, whichever occurs first. This same value of R11 sets the OV
threshold to 450 V. If exceeded, for example during a line surge,
TOPSwitch-GX stops switching for the duration of the surge
extending the high voltage withstand to 700 V without device
damage.

Capacitor C11 has been added in parallel with VR1 to reduce
Zener clamp dissipation. With a switching frequency of
132 kHz a PQ26/20 core can be used to provide 70 W. To
maximize efficiency, by reducing winding losses, two output
windings are used each with their own dual 100 V Schottky
rectifier (D2 and D3). The frequency reduction feature of the
TOPSwitch-GX eliminates any dummy loading to maintain
regulation at no-load and reduces the no-load consumption of
the power supply to only 520 mW at 230 VAC input. Frequency
jittering provides conducted EMI meeting the CISPR 22
(FCC B) / EN55022B specification, using simple filter
components (C7, L2, L3 and C6) even with the output earth
grounded.

To regulate the output an optocoupler (U2) is used with a
secondary reference sensing the output voltage via a resistor
divider (U3, R4, R5, R6). Diode D4 and C15 filter and smooth
the output of the bias winding. Capacitor C15 (1uF) prevents
the bias voltage from falling during zero to full load transients.
Resistor R8 provides filtering of leakage inductance spikes
keeping the bias voltage constant even at high output loads.
Resistor R7, C9 and C10 together with C5 and R3 provide loop
compensation.

Due to the large primary currents, all the small signal control
components are connected to a separate source node that is
Kelvin connected to the source pin of the TOPSwitch-GX. For
improved common mode surge immunity the bias winding
common returns directly to the DC bulk capacitor (C1).

Figure 42. 70 W Power Supply using Current Limit Reduction with Line and Line Sensing for UV and OV.

19 V
@ 3.6 A

TOP249Y

U1

U3

TL431

U2

PC817A

DL

SXF

C

RTN

L2

820 µH

2A

C6

0.1 µF
X2

F1

3.15 A

85-265 VAC

BR1

RS805

8A 600 V

L3
75 µH
2A

t°

T1

C13

0.33 µF
400 V

C12

0.022 µF
400 V

C11

0.01 µF
400 V

RT1

10 Ω

1.7 A

PI-2691-033001

All resistors 1/8 W 5% unless otherwise stated.

J1

L

N

CONTROL

CONTROL

TOPSwitch-GX

C1

150 µF

400 V

PERFORMANCE SUMMARY
Output Power: 70 W

Regulation: ± 4%
Efficiency: ≥ 84%
Ripple: ≤ 120 mV pk-pk
No Load Consumption: < 0.52 W @ 230 VAC

C5

47 µF

16 V

C3

820 µF

25 V

L1

200 µH

C2

820 µF

25 V

C14

0.1 µF
50 V

C4

820 µF

25 V

C10

0.1 µF
50 V

C9

4.7 nF 50 V

C8

0.1 µF
50 V

VR1
P6KE­200

D2
MBR20100

C7 2.2 nF

Y1 Safety

D3
MBR20100

D4
1N4148

R11

2 MΩ

1/2 W

R9

13 MΩ

R8

4.7 Ω

R1

270 Ω

R2

1 kΩ

R5

562 Ω

1%

R4

31.6 kΩ
1%

R7

56 kΩ

R10

20.5 kΩ

R3

6.8 Ω
R6

4.75 kΩ
1%

C15
1 µF
50 V

D1
UF4006

TOP242-249

23

August 8, 2000

E

7/01

A High Efficiency, 250 W, 250 – 380 VDC Input Power Supply

The circuit shown in figure 43 delivers 250 W (48 V @ 5.2 A)
at 84% efficiency using a TOP249 from a 250 to 380 VDC
input. DC input is shown, as typically at this power level a p.f.c.
boost stage would preceed this supply, providing the DC input
(C1 is included to provide local decoupling). Flyback topology
is still useable at this power level due to the high output voltage,
keeping the secondary peak currents low enough so that the
output diode and capacitors are reasonably sized.

In this example the TOP249 is at the upper limit of its power
capability and the current limit is set to the internal maximum
by connecting the X pin to SOURCE. However, line sensing is
implemented by connecting a 2 MΩ resistor from the L pin to
the DC rail. If the DC input rail rises above 450 VDC, then
TOPSwitch-GX will stop switching until the voltage returns to
normal, preventing device damage.

Due to the high primary current, a low leakage inductance
transformer is essential. Therefore, a sandwich winding with a
copper foil secondary was used. Even with this technique the
leakage inductance energy is beyond the power capability of a
simple Zener clamp. Therefore, R2, R3 and C6 are added in
parallel to VR1. These have been sized such that during normal
operation very little power is dissipated by VR1, the leakage
energy instead being dissipated by R2 and R3. However, VR1

is essential to limit the peak drain voltage during start-up and/
or overload conditions to below the 700 V rating of the
TOPSwitch-GX MOSFET.

The secondary is rectifed and smoothed by D2 and C9, C10 and
C11. Three capacitors are used to meet the secondary ripple
current requirement. Inductor L2 and C12 provide switching
noise filtering.

A simple Zener sensing chain regulates the output voltage. The
sum of the voltage drop of VR2, VR3 and VR4 plus the LED
drop of U2 gives the desired output voltage. Resistor R6 limits
LED current and sets overall control loop DC gain. Diode D4
and C14 provide secondary soft-finish, feeding current into the
CONTROL pin prior to output regulation and thus ensuring that
the output voltage reaches regulation at start-up under low line,
full load conditions. Resistor R9 provides a discharge path for
C14. Capacitor C13 and R8 provide control loop compensation
and are required due to the gain associated with such a high
output voltage.

Sufficient heat sinking is required to keep the TOPSwitch-GX
device below 110 °C when operating under full load, low line
and maximum ambient temperature. Airflow may also be
required if a large heat sink area is not acceptable.

Figure 43. 250 W, 48 V Power Supply using TOP249.

48 V @ 5.2 A

+250 - 380 VDC

0V

LD

SXF

C

RTN

PI-2692-033001

All resistor 1/8 W 5% unless
otherwise stated.

CONTROL

TOPSwitch-GX

C1
22 µF
400 V

C3

0.1 µF
50 V

R4

6.8 Ω

R6

100 Ω

R8

56 Ω

R9

10 kΩ

C3

47 µF

10 V

C6

4.7 nF
1 kV

C13

150 nF

63 V

C4
1 µF
50 V

C14

22 µF

63 V

C9

560 µF

63 V

C10

560 µF

63 V

C11

560 µF

63 V

C12

68 µF

63 V

C7

2.2 nF Y1
L2

3 µH 8A

D2
MUR1640CT

D2
1N4148

U2

LTV817A

D1

BYV26C

T1

R1
2 MΩ
1/2 W

R3

68 kΩ

2 W

R2

68 kΩ

2 W

VR1

P6KE200

VR2 22 V

BZX79B22

VR3 12 V

BZX79B12

VR4 12 V

BZX79B12

CONTROL

D4
1N4148

PERFORMANCE SUMMARY
Output Power: 250 W

Line Regulation: ± 1%
Load Regulation: ± 5%
Efficiency: ≥ 85%
Ripple: < 100 mV pk-pk
No Load Consumption: ≤ 1.4 W (300 VDC)

TOP249Y

U1

TOP242-249

24

E
7/01

August 8, 2000

Multiple Output, 60 W, 185-265 VAC Input Power Supply

Figure 44 shows a multiple output supply typical for high end
set-top boxes or cable decoders containing high capacity hard
disks for recording. The supply delivers an output power of
45 W cont./60 W peak (thermally limited) from an input voltage
of 185 to 265 VAC. Efficiency at 45 W, 185 VAC is ≥ 75%.

The 3.3 V and 5 V outputs are regulated to ±5% without the need
for secondary linear regulators. DC stacking (the secondary
winding reference for the other output voltages is connected to
the cathode of D10 rather than the anode) is used to minimize
the voltage error for the higher voltage outputs.

Due to the high ambient operating temperature requirement
typical of a set-top box (60 °C) the TOP246Y is used to reduce
conduction losses and minimize heat sink size. Resistor R2 sets
the device current limit to 80% of typical to limit overload
power. The line sense resistor (R1) protects the TOPSwitch-GX
from line surges and transients by sensing when the DC rail
voltage rises to above 450 V. In this condition the
TOPSwitch-GX stops switching, extending the input voltage
withstand to 496 VAC which is ideal for countries with poor
power quality. A thermistor (RT1) is used to prevent premature
failure of the fuse by limiting the inrush current (due to the
relatively large size of C2). An optional MOV (RV1) extends
the differential surge protection to 6 kV from 4 kV.

Leakage inductance clamping is provided by VR1, R5 and C5,
keeping the DRAIN voltage below 700 V under all conditions.
Resistor R5 and capacitor C5 are selected such that VR1
dissipates very little power except during overload conditions.
The frequency jittering feature of TOPSwitch-GX allows the
circuit shown to meet CISPR22B with simple EMI filtering
(C1, L1 and C6) and the output grounded.

The secondaries are rectified and smoothed by D7 to D11, C7,
C9, C11, C13, C14, C16 and C17. Diode D11 for the 3.3 V
output is a Schottky diode to maximize efficiency. Diode D10
for the 5 V output is a PN type to center the 5 V output at 5 V.
The 3.3 V and 5 V output require two capacitors in parallel to
meet the ripple current requirement. Switching noise filtering
is provided by L2 to L5 and C8, C10, C12, C15 and C18.
Resistor R6 prevents peak charging of the lightly loaded 30 V
output. The outputs are regulated using a secondary reference
(U3). Both the 3.3 V and 5 V outputs are sensed via R11 and
R10. Resistor R8 provides bias for U3 and R7 sets the overall
DC gain. Resistor R9, C19, R3 and C4 provide loop
compensation. A soft-finish capacitor (C20) eliminates output
overshoot.

Figure 44. 60 W Multiple Output Power Supply using TOP246.

D6

1N4148

D7
UF4003

D8
UF5402

D9
UF5402

D11
MBR1045

D10
BYV32-200

T1

U2

LTV817

U3
TL431

C20

22 µF

10 V

R7

150 Ω

R12
10 k

C19

0.1 µF

R11

9.53
kΩ

R10

15.0
kΩ

R9

3.3 kΩ

R8

1 kΩ

C6

2.2 nF
Y1

C7

47 µF

50 V

C9

330 µF

25 V

C11

390 µF

35 V

C14

1000 µF

25 V

30 V @

0.03 A

18 V @

0.5 A

12 V @

0.6 A

5 V @

3.2 A

3.3 V @
3 A

RTN

D1-D4

1N4007 V

F1

3.15 A

RV1

275 V

14 mm

J1

L1

20 mH

0.8A

t°

L

N

R3

6.8 Ω
C5

47 µF

10 V

TOP246Y

U1

DL

S

C

TOPSwitch-GX

R1

2 MΩ
1/2 W

R5

68 kΩ

2 W

R6

10 Ω

RT1

10 Ω

1.7 A

C2
68 µF
400 V

C5

1 nF

400 V

C3
1 µF
50 V

C1

0.1 µF
X1

PI-2693-033001

CONTROL

CONTROL

C3

0.1 µF
50 V

XF

D6
1N4937

VR1

P6KE170

C16

1000 µF

25 V

C13

1000 µF

25 V

C17

1000 µF

25 V

C15

220 µF

165 V

C18

220 µF

16 V

C12

100 µF

25 V

C10

100 µF

25 V

C8

10 µF

50 V

L2

3.3 µH
3A

L3

3.3 µH
3A

L4

3.3 µH
5A

L5

3.3 µH
5A

PERFORMANCE SUMMARY
Output Power: 45 W Cont./60 W Peak

Regulation:

3.3 V: ± 5%
5 V: ± 5%
12 V: ± 7%
18 V: ± 7%
30 V: ± 8%
Efficiency: ≥75%
No Load Consumption: 0.6 W

185-265 VAC

.R2

9.08 kΩ

TOP242-249

25

August 8, 2000

E

7/01

Processor Controlled Supply Turn On/Off

A low cost momentary contact switch can be used to turn the
TOPSwitch-GX power on and off under microprocessor control
that may be required in some applications such as printers. The
low power remote off feature allows an elegant implementation
of this function with very few external components as shown in
Figure 45. Whenever the push button momentary contact
switch P1 is closed by the user, the optocoupler U3 is activated
to inform the microprocessor of this action. Initially, when the
power supply is off (M pin is floating), closing of P1 turns the
power supply on by shorting the M pin of the TOPSwitch-GX
to SOURCE through a diode (remote on). When the secondary
output voltage VCC is established, the microprocessor comes
alive and recognizes that the switch P1 is closed through the
switch status input that is driven by the optocoupler U3 output.
The microprocessor then sends a power supply control signal to
hold the power supply in the on-state through the optocoupler
U4. If the user presses the switch P1 again to command a turn
off, the microprocessor detects this through the optocoupler U3
and initiates a shutdown procedure that is product specific. For
example, in the case of the inkjet printer, the shutdown procedure
may include safely parking the print heads in the storage

position. In the case of products with a disk drive, the shutdown
procedure may include saving data or settings to the disk. After
the shutdown procedure is complete, when it is safe to turn off
the power supply, the microprocessor releases the M pin by
turning the optocoupler U4 off. If the manual switch and the
optocouplers U3 and U4 are not located close to the M pin, a
capacitor CM may be needed to prevent noise coupling to the pin
when it is open.

The power supply could also be turned on remotely through a
local area network or a parallel or serial port by driving the
optocoupler U4 input LED with a logic signal. Sometimes it is
easier to send a train of logic pulses through a cable (due to AC
coupling of cable, for example) instead of a DC logic level as
a wake up signal. In this case, a simple RC filter can be used to
generate a DC level to drive U4 (not shown in Figure 45). This
remote on feature can be used to wake up peripherals such as
printers, scanners, external modems, disk drives, etc., as needed
from a computer. Peripherals are usually designed to turn off
automatically if they are not being used for a period of time, to
save power.

U1

U2

U4

U3

C

M

P1

P1 Switch

Status

Power
Supply

ON/OFF

Control

External
Wake-up

Signal

PI-2561-033001

V

CC

(+5 V)

RETURN

CONTROL

MICRO
PROCESSOR/
CONTROLLER

LOGIC

INPUT

LOGIC

OUTPUT

High Voltage

DC Input

+

-

TOPSwitch-GX

DM

SF

C

1N4148

U4

LTV817A

6.8 kΩ

1 nF

100 kΩ

6.8 kΩ

U3

LTV817A

27 kΩ

1N4148

47 µF

Figure 45. Remote ON/OFF using Microcontroller.

TOP242-249

26

E
7/01

August 8, 2000

In addition to using a minimum number of components,
TOPSwitch-GX provides many technical advantages in this
type of application:

1. Extremely low power consumption in the off mode: 80 mW
typical at 110 VAC and 160 mW typical at 230 VAC. This
is because in the remote/off mode the TOPSwitch-GX
consumes very little power, and the external circuitry does
not consume any current (either M, L or X pin is open) from
the high voltage DC input.

2. A very low cost, low voltage/current, momentary contact
switch can be used.

3. No debouncing circuitry for the momentary switch is required.
During turn-on, the start-up time of the power supply
(typically 10 to 20 ms) plus the microprocessor initiation
time act as a debouncing filter, allowing a turn-on only if the
switch is depressed firmly for at least the above delay time.
During turn-off, the microprocessor initiates the shutdown

sequence when it detects the first closure of the switch, and
subsequent bouncing of the switch has no effect. If necessary,
the microprocessor could implement the switch debouncing
in software during turn-off, or a filter capacitor can be used
at the switch status input.

4. No external current limiting circuitry is needed for the
operation of the U4 optocoupler output due to internal
limiting of M pin current.

5. No high voltage resistors to the input DC voltage rail are
required to power the external circuitry in the primary. Even
the LED current for U3 can be derived from the CONTROL
pin. This not only saves components and simplifies layout,
but also eliminates the power loss associated with the high
voltage resistors in both on and off states.

6. Robust design: There is no on/off latch that can be accidentally
triggered by transients. Instead, the power supply is held in
the on-state through the secondary side microprocessor.

TOP242-249

27

August 8, 2000

E

7/01

Key Application Considerations

TOPSwitch-II

vs.

TOPSwitch-GX

Table 4 compares the features and performance differences
between TOPSwitch-GX and TOPSwitch-II. Many of the new
features eliminate the need for additional discrete components.

Other features increase the robustness of design allowing cost
savings in the transformer and other power components.

Function

TOPSwitch-II TOPSwitch-GX

Figures

TOPSwitch-GX

Advantages

Soft-Start N/A* 10 ms • Limits peak current and voltage

component stresses during start-up

• Eliminates external components
used for soft-start in most
applications

• Reduces or eliminates output
overshoot

External Current Limit N/A* Programmable 11,20,21, • Smaller transformer

100% to 30% of 24,25,27, • Higher efficiency
default current 28,34,35, • Allows power limiting (constant over­limit 38,39 load power independent of line

voltage

• Allows use of larger device for lower
losses, higher efficiency and smaller
heatsink

DC

MAX

67% 78% 7 • Smaller input cap (wider dynamic

range)

• Higher power capability (when used
with RCD clamp for large VOR)

• Allows use of Schottky secondary
rectifier diode for up to 15 V output
for high efficiency

Line Feed Forward with N/A* 78% to 38% 7,11,17, • Rejects line ripple
DC

MAX

Reduction 26,27,28,

31,40

Line OV Shutdown N/A* Single resistor 11,17,19, • Increases voltage withstand cap-

programmable 26,27,28, ability against line surge

31,33,40

Line UV Detection N/A* Single resistor 11,17,18, • Prevents auto-restart glitches

programmable 26,27,28, during power down

31,32,40

Switching Frequency 100 kHz ±10% 132 kHz ±6% 13,15 • Smaller transformer

• Below start of conducted EMI limits

Switching Frequency N/A* 66 kHz ±7% 14,15 • Lower losses when using RC and
Option (Y and R RCD snubber for noise reduction in
Packages) video applications

• Allows for higher efficiency in
standby mode

• Lower EMI (second harmonic below
150 kHz)

Frequency Jitter N/A* ±4 kHz@132 kHz 9,46 • Reduces conducted EMI

±2 kHz@66 kHz

Frequency Reduction N/A* At a Duty Cycle 7 • Zero load regulation without dummy

below 10% load

• Low power consumption at no load

Table 4. Comparison Between TOPSwitch-II and TOPSwitch-GX. (continued on next page) *Not available

TOP242-249

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Table 4 (cont). Comparison Between TOPSwitch-II and TOPSwitch-GX. *Not available

Function

TOPSwitch-FX TOPSwitch-GX TOPSwitch-GX

Advantages

Light Load Operation Cycle skipping Frequency and Duty Cycle • Improves light load efficiency

reduction • Reduces no-load consumption

Line Sensing/Externally Line sensing and Line sensing and externally • Additional design flexibility allows all
Set Current Limit externally set set current limit possible features to be used simultaneously
(Y and R Packages) current limit simultaneously

mutually (functions split onto
exclusive (M pin) L and X pins)

Current Limit 100-40% 100-30% • Minimizes transformer core size
Programming in highly continuous designs
Range

TOPSwitch-FX

vs.

TOPSwitch-GX

Table 5 compares the features and performance differences
between TOPSwitch-GX and TOPSwitch-FX. Many of the new
features eliminate the need for additional discrete components.

Other features increase the robustness of design allowing cost
savings in the transformer and other power components.

Function

TOPSwitch-II TOPSwitch-GX

Figures

TOPSwitch-GX

Advantages

Remote ON/OFF N/A* Single transistor 11, 22, • Fast on/off (cycle by cycle)

or optocoupler 23, 24, • Active-on or active-off control
interface or manual 25, 26, • Low consumption in remote off state
switch 27, 29, • Active-on control for fail-safe

36, 37, • Eliminates expensive in-line on/off
38, 39, switch
40 • Allows processor controlled turn

on/off

• Permits shutdown/wake-up of
peripherals via LAN or parallel port

Synchronization N/A* Single transistor • Synchronization to external lower

or optocoupler frequency signal
interface • Starts new switching cycle on

demand

Thermal Shutdown 125 °C min. Hysteretic 130 °C • Automatic recovery from thermal

Latched min. Shutdown (with fault

75 °C hysteresis) • Large hysteresis prevents circuit

board overheating

Current Limit Tolerance ±10% (@25 °C) ±7% (@25 °C) • 10% higher power capability due to

-8% (0 °C to100 °C) -4% (0 °C to 100 °C) tighter tolerance

DRAIN DIP 0.037" / 0.94 mm 0.137" / 3.48 mm • Greater immunity to arcing as a
Creepage SMD 0.037" / 0.94 mm 0.137" / 3.48 mm result of build-up of dust, debris and
at Package TO-220 0.046" / 1.17 mm 0.068" / 1.73 mm other contaminants
DRAIN Creepage at 0.045" / 1.14 mm 0.113" / 2.87 mm • Preformed leads accommodate
PCB for Y and R (R Package N/A*) (preformed leads) large creepage for PCB layout
Packages • Easier to meet Safety (UL/VDE)

Table 5. Comparison Between TOPSwitch-FX and TOPSwitch-GX. (continued on next page)

TOP242-249

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Table 5 (cont). Comparison Between TOPSwitch-FX and TOPSwitch-GX. *Not available

TOPSwitch-GX

Design Considerations

Power Table

Datasheet power table represents the maximum practical
continuous output power based on the following conditions:
TOP242 to TOP246: 12 V output, Schottky output diode,
150 V reflected voltage (VOR) and efficiency estimates from
curves contained in application note AN-29. TOP247 to TOP249:
Higher output voltages used with a maximum output current of
6 A.

For all devices a 100 VDC minimum for 85-265 VAC and 250
VDC minimum for 230 VDC are assumed and sufficient heat
sinking to keep device temperature ≤ 100 °C. Power levels
shown in the power table for the R package device assume

6.45 cm2 of 610 g/m2 copper heat sink area in an enclosed
adapter, or 19.4 cm2 in an open frame.

TOPSwitch-GX Selection

Selecting the optimum TOPSwitch-GX depends upon required
maximum output power, efficiency, heat sinking constraints
and cost goals. With the option to externally reduce current
limit, a larger TOPSwitch-GX may be used for lower power

Function

TOPSwitch-FX TOPSwitch-GX TOPSwitch-GX

Advantages

P/G Package Current Identical to Y TOP243P or G and • Matches device current limit to
Limits packages TOP244P or G internal package dissipation capability

current limits reduced • Allows more continuous design to

lower device dissipation (lower RMS
currents)

Y/R Package Current 100% 90% (for equivalent R

DS (ON)

) • Minimizes transformer core size

Limits (R package N/A*) • Optimizes efficiency for most

applications

Thermal Shutdown 125 °C min. 130 °C min. 75 °C • Allows higher output powers in

70 °C hysteresis hysteresis high ambient temperature

applications

Maximum Duty Cycle 90 µA 60 µA • Reduces output line frequency
Reduction Threshold ripple at low line

• D

MAX

reduction optimized for

forward design

Line Under-Voltage N/A* 40% of positive (turn-on) • Provides a well defined turn-off
Negative (turn-off) threshold threshold as the line voltage falls
Threshold

Soft-Start 10 ms (duty cycle) 10 ms (duty cycle + current • Gradually increasing current limit

limit) in addition to duty cycle during soft-

start further reduces peak current
and voltage

• Further reduces component
stresses during start up

applications where higher efficiency is needed or minimal heat
sinking is available.

Input Capacitor

The input capacitor must be chosen to provide the minimum
DC voltage required for the TOPSwitch-GX converter to maintain
regulation at the lowest specified input voltage and maximum
output power. Since TOPSwitch-GX has a higher DC

MAX

than
TOPSwitch-II, it is possible to use a smaller input capacitor.
For TOPSwitch-GX, a capacitance of 2 µF per watt is possible
for universal input with an appropriately designed transformer.

Primary Clamp and Output Reflected Voltage V

OR

A primary clamp is necessary to limit the peak TOPSwitch-GX
drain to source voltage. A Zener clamp requires few parts and
takes up little board space. For good efficiency, the clamp
Zener should be selected to be at least 1.5 times the output
reflected voltage V

OR

as this keeps the leakage spike conduction
time short. When using a Zener clamp in a universal input
application, a VOR of less than 135 V is recommended to allow
for the absolute tolerances and temperature variations of the
Zener. This will ensure efficient operation of the clamp circuit
and will also keep the maximum drain voltage below the rated
breakdown voltage of the TOPSwitch-GX MOSFET.

TOP242-249

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August 8, 2000

Figure 46b. TOPSwitch-GX Full Range EMI Scan (132 kHz,

with jitter) with Identical Circuitry and
Conditions.

A high VOR is required to take full advantage of the wider DC

MAX

of TOPSwitch-GX. An RCD clamp provides tighter clamp
voltage tolerance than a Zener clamp and allows a V

OR

as high
as 150 V. RCD clamp dissipation can be minimized by
reducing the external current limit as a function of input line
voltage (see Figure 21 and 35). The RCD clamp is more cost
effective than the Zener clamp but requires more careful design
(see quick design checklist).

Output Diode

The output diode is selected for peak inverse voltage, output
current, and thermal conditions in the application (including
heatsinking, air circulation, etc.). The higher DC

MAX

of
TOPSwitch-GX along with an appropriate transformer turns
ratio can allow the use of a 60 V Schoktty diode for higher
efficiency on output voltages as high as 15 V (see Figure 41. A
12 V, 30 W design using a 60 V Schottky for the output diode).

Bias Winding Capacitor

Due to the low frequency operation at no-load a 1µF bias
winding capacitor is recommended.

Soft-Start

Generally a power supply experiences maximum stress at start­up before the feedback loop achieves regulation. For a period
of 10 ms the on-chip soft-start linearly increases the duty cycle
from zero to the default DC

MAX

at turn on. In addition, the
primary current limit increases from 85% to 100% over the
same period. This causes the output voltage to rise in an orderly
manner allowing time for the feedback loop to take control of
the duty cycle. This reduces the stress on the TOPSwitch-GX
MOSFET, clamp circuit and output diode(s), and helps prevent
transformer saturation during start-up. Also soft-start limits the
amount of output voltage overshoot, and in many applications
eliminates the need for a soft-finish capacitor.

EMI

The frequency jitter feature modulates the switching frequency
over a narrow band as a means to reduce conducted EMI peaks
associated with the harmonics of the fundamental switching
frequency. This is particularly beneficial for average detection
mode. As can be seen in Figure 46, the benefits of jitter increase
with the order of the switching harmonic due to an increase in
frequency deviation.

The FREQUENCY pin of TOPSwitch-GX offers a switching
frequency option of 132 kHz or 66 kHz. In applications that
require heavy snubbers on the drain node for reducing high
frequency radiated noise (for example, video noise sensitive
applications such as VCR, DVD, monitor, TV, etc.), operating
at 66 kHz will reduce snubber loss resulting in better efficiency.
Also, in applications where transformer size is not a concern,
use of the 66 kHz option will provide lower EMI and higher
efficiency. Note that the second harmonic of 66 kHz is still
below 150 kHz, above which the conducted EMI specifications
get much tighter.

For 10 W or below, it is possible to use a simple inductor in
place of a more costly AC input common mode choke to meet
worldwide conducted EMI limits.

Transformer Design

It is recommended that the transformer be designed for maximum
operating flux density of 3000 Gauss and a peak flux density of
4200 Gauss at maximum current limit. The turns ratio should be
chosen for a reflected voltage (VOR) no greater than 135 V when
using a Zener clamp, or 150 V (max) when using RCD clamp
with current limit reduction with line voltage (overload
protection).

For designs where operating current is significantly lower than
the default current limit, it is recommended to use an externally
set current limit close to the operating peak current to reduce
peak flux density and peak power (see Figure 20 and 34). In
most applications, the tighter current limit tolerance, higher

-20

-10

0

-10

20

30

40

50

60

70

80

0.15 1 10 30

Frequency (MHz)

Amplitude (dBµV)

PI-2576-010600

EN55022B (QP)
EN55022B (AV)

TOPSwitch-II (no jitter)

EN55022B (QP)
EN55022B (AV)

-20

-10

0

-10

20

30

40

50

60

70

80

0.15 1 10 30

Frequency (MHz)

Amplitude (dBµV)

PI-2577-010600

TOPSwitch-GX (with jitter)

Figure 46a. TOPSwitch-II Full Range EMI Scan

(100 kHz, no jitter)

TOP242-249

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switching frequency and soft-start features of TOPSwitch-GX
contribute to a smaller transformer when compared to

TOPSwitch-II.

Standby Consumption

Frequency reduction can significantly reduce power loss at
light or no load, especially when a Zener clamp is used. For very
low secondary power consumption use a TL431 regulator for
feedback control. Alternately, switching losses can be
significantly reduced by changing from 132 kHz in normal
operation to 66 kHz under light load conditions.

TOPSwitch-GX

Layout Considerations

As TOPSwitch-GX has additional pins and operates at much
higher power levels compared to previous TOPSwitch
families, the following guidelines should be carefully
followed.

Primary Side Connections

Use a single point (Kelvin) connection at the negative terminal
of the input filter capacitor for TOPSwitch-GX source pin and
bias winding return. This improves surge capabilities by returning
surge currents from the bias winding directly to the input filter
capacitor.

The CONTROL pin bypass capacitor should be located as
close as possible to the SOURCE and CONTROL pins and its
SOURCE connection trace should not be shared by the main
MOSFET switching currents. All SOURCE pin referenced
components connected to the MULTI-FUNCTION, LINE­SENSE or EXTERNAL CURRENT LIMIT pins should also be
located closely between their respective pin and SOURCE.
Once again the SOURCE connection trace of these components
should not be shared by the main MOSFET switching currents.
It is very critical that SOURCE pin switching currents are
returned to the input capacitor negative terminal through a
seperate trace that is not shared by the components connected
to CONTROL, MULTI-FUNCTION, LINE-SENSE or
EXTERNAL CURRENT LIMIT pins. This is because the
SOURCE pin is also the controller ground reference pin.

Any traces to the M, L or X pins should be kept as short as
possible and away from the DRAIN trace to prevent noise
coupling. LINE-SENSE resistor (R1 in figures 47-49) should
be located close to the M or L pin to minimize the trace length
on the M or L pin side.

In addition to the 47 µF CONTROL pin capacitor, a high
frequency bypass capacitor in parallel may be used for better
noise immunity. The feedback optocoupler output should also
be located close to the CONTROL and SOURCE pins of

TOPSwitch-GX.

Y-Capacitor

The Y-capacitor should be connected close to the secondary
output return pin(s) and the positive primary DC input pin of the
transformer.

Heat Sinking

The tab of the Y package (TO-220) is internally electrically
tied to the SOURCE pin. To avoid circulating currents, a heat
sink attached to the tab should not be electrically tied to any
primary ground/source nodes on the PC board.

When using a P (DIP-8), G (SMD-8) or R (TO-263) package,
a copper area underneath the package connected to the SOURCE
pins will act as an effective heat sink. On double sided boards
(Figure 49), top side and bottom side areas connected with vias
can be used to increase the effective heat sinking area.

In addition, sufficient copper area should be provided at the
anode and cathode leads of the output diode(s) for heat sinking.

In Figures 47, 48 and 49 a narrow trace is shown between the
output rectifier and output filter capacitor. This trace acts as a
thermal relief between the rectifier and filter capacitor to
prevent excessive heating of the capacitor.

Quick Design Checklist

As with any power supply design, all TOPSwitch-GX designs
should be verified on the bench to make sure that components
specifications are not exceeded under worst case conditions.
The following minimum set of tests is strongly recommended:

1. Maximum drain voltage – Verify that peak VDS does not
exceed 675 V at highest input voltage and maximum overload
output power. Maximum overload output power occurs
when the output is overloaded to a level just before the
power supply goes into auto-restart (loss of regulation).

2. Maximum drain current – At maximum ambient temperature,
maximum input voltage and maximum output load, verify
drain current waveforms at start-up for any signs of
transformer saturation and excessive leading edge current
spikes. TOPSwitch-GX has a leading edge blanking time of
220 ns to prevent premature termination of the on-cycle.
Verify that the leading edge current spike is below the
allowed current limit envelope (see Figure 52) for the drain
current waveform at the end of the 220 ns blanking period.

3. Thermal check – At maximum output power, minimum
input voltage and maximum ambient temperature, verify
that temperature specifications are not exceeded for
TOPSwitch-GX, transformer, output diodes and output
capacitors. Enough thermal margin should be allowed for

TOP242-249

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Figure 47. Layout Considerations for TOPSwitch-GX using P or G Packages.

Figure 48. Layout Considerations for TOPSwitch-GX using Y Package.

+

-

Input Filter Capacitor

Heat Sink

Safety Spacing

Opto-

coupler

+-

DC

Out

Output Filter Capacitor

T

r
a
n
s

f

o

r

m

e

r

SEC

D

L

C

Maximize hatched copper
areas ( ) for optimum
heat sinking

Y1-

Capacitor

PI-2669-042301

TOP VIEW

TOPSwitch-GX

HV

R1

X

Output Rectifier

TOP VIEW

PI-2670-042301

Y1-

Capacitor

Opto-

coupler

D

+

-

HV

R2

+-

DC

Out

Input Filter Capacitor

Output Filter Capacitor

Output Rectifier

Safety Spacing

T

r
a
n
s

f
o

r

m

e

r

Maximize hatched copper
areas ( ) for optimum
heat sinking

S

PRI

PRI

SEC

S

S

S

C

BIAS

BIAS

M

R1

TOPSwitch-GX

TOP242-249

33

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the part-to-part variation of the R

DS(ON)

of TOPSwitch-GX as
specified in the data sheet. The margin required can either
be calculated from the tolerances or it can be accounted for
by connecting an external resistance in series with the
DRAIN pin and attached to the same heatsink, having a
resistance value that is equal to the difference between the
measured R

DS(ON)

of the device under test and the worst case

maximum specification.

Figure 49. Layout Considerations for TOPSwitch-GX using R Package.

Design Tools

Up to date information on design tools can be found at the
Power Integrations Web site: www.powerint.com

-

HV

+-

DC

Out

PI-2734-043001

T

r
a
n
s

f
o

r

m

e

r

Safety Spacing

Y1-

Capacitor

Solder Side
Component Side

Opto-

coupler

+

Output Filter Capacitors

Maximize hatched copper
areas( ) for optimum
heat sinking

TOP VIEW

Input Filter

Capacitor

R1a - 1c

PRI

PRI

SEC

BIAS

TOPSwitch-GX

S

L

C

X

D

TOP242-249

34

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August 8, 2000

ABSOLUTE MAXIMUM RATINGS

(1)

DRAIN Voltage ............................................ -0.3 to 700 V

DRAIN Peak Current: TOP242 ...............................0.72 A

TOP243 ...............................1.44 A

TOP244 ...............................2.16 A

TOP245 ...............................2.88 A

TOP246 ...............................4.32 A

TOP247 ...............................5.76 A

TOP248 ...............................7.20 A

TOP249 ...............................8.64 A

CONTROL Voltage .......................................... -0.3 to 9 V

CONTROL Current ...............................................100 mA

I

C

= 3 mA;

TJ = 25 °C

IC = I

CD1

f

OSC

DC

(ONSET)

f

OSC (DMIN)

∆f

f

M

DC

MAX

t

SOFT

CONTROL FUNCTIONS

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V; TJ = -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

THERMAL IMPEDANCE

kHz

%

kHz

kHz

Hz

%

ms

Thermal Impedance: Y Package (θJA)

(1)

............... 70 °C/W

(θJC)

(2)

................ 2 °C/W

P or G Package:

(θJA) ......45 °C/W

(3)

; 35 °C/W

(4)

(θJC)

(5)

......................... 11 °C/W

Notes:

1. Free standing with no heatsink.

2. Measured at the back surface of tab.

3. Soldered to 0.36 sq. inch (232 mm2), 2oz. (610 gm/m2) copper clad.

4. Soldered to 1 sq. inch (645 mm2), 2oz. (610 gm/m2) copper clad.

5. Measured on the SOURCE pin close to plastic interface.

124 132 140

61.5 66 70.5

10

30
15

± 4
± 2

250

75 78 83
28 38 50

10 15

FREQUENCY Pin

Connected to SOURCE

FREQUENCY Pin

Connected to CONTROL

132 kHz Operation

66 kHz Operation

IL ≤ I

L (DC)

or IM ≤ I

M(DC)

IL or IM = 190 µA

TJ = 25 °C; DC

MIN to DCMAX

Switching
Frequency
(average)

Duty Cycle at
ONSET of Fre­quency Reduction

Switching
Frequency near
0% Duty Cycle

Frequency Jitter
Deviation

Frequency Jitter
Modulation Rate

Maximum Duty
Cycle

Soft Start Time

132 kHz Operation

66 kHz Operation

LINE SENSE Pin Voltage ................................ -0.3 to 9 V

CURRENT LIMIT Pin Voltage ..................... -0.3 to 4.5 V

MULTI-FUNCTION Pin Voltage .................... -0.3 to 9 V

FREQUENCY Pin Voltage............................... -0.3 to 9 V

Storage Temperature .....................................-65 to 150 °C

Operating Junction Temperature

(2)

...............-40 to 150 °C

Lead Temperature

(3)

............................................... 260 °C

Notes:

1. All voltages referenced to SOURCE, TA = 25 °C.

2. Normally limited by internal circuitry.

3. 1/16" from case for 5 seconds.

TOP242-249

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CONTROL FUNCTIONS (cont.)

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

J

= -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

See Note A

See Figure 7

TJ = 25 °C

IC = 4 mA; TJ = 25 °C

See Figure 51

DC

reg

l

B

lC

(OFF)

Z

C

PWM Gain
Temperature Drift

External Bias
Current

CONTROL
Current at 0%
Duty Cycle

Dynamic
Impedance

Dynamic
Impedance
Temperature Drift

Control Pin
Internal Filter Pole

%/mA/°C

mA

mA

Ω

%/°C

kHz

SHUTDOWN/AUTO-RESTART

VC = 0 V
VC = 5 V

l

C (CH)

V

C(AR)U

V

C(AR)L

V

C(AR)hyst

DC

(AR)

f

(AR)

Control Pin
Charging Current

Charging Current
Temperature Drift

Auto-restart Upper
Threshold Voltage

Auto-restart Lower
Threshold Voltage

Auto-restart
Hysteresis Voltage

Auto-restart Duty
Cycle

Auto-restart
Frequency

mA

%/°C

V

V

V

%

Hz

-5.0 -3.5 -2.0

-3.0 -1.8 -0.6

0.5

5.8

4.5 4.8 5.1

0.8 1.0

48

1.0

TJ = 25 °C

See Note A

PWM Gain IC = 4 mA; T

J

= 25 °C -28 -23 -18 %/mA

TOP242-245
TOP246-249

TOP242-245
TOP246-249

-0.01

1.2 2.0 3.0

1.6 2.6 4.0

6.0 7.0

6.6 8.0

10 15 22

0.18

7

TOP242-249

36

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August 8, 2000

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

J

= -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

µA

µA

µA

µA

V

µA

µA

µA

µA

V

V

V

µA

%/µA

mA

44 50 54

30

210 225 240

8

0.5 1.0 1.6

-35 -27 -20

5

300 400 520

-300 -240 -180

-110 -90 -70

1.90 2.50 3.00

2.30 2.90 3.30

1.26 1.33 1.40

1.18 1.24 1.30

1.24 1.31 1.39

1.13 1.19 1.25

40 60 75

0.25

0.6 1.0

1.0 1.6

TJ = 25 °C

TJ = 25 °C

Threshold

Hysteresis

TJ = 25 °C

Threshold

Hysteresis

Line Under-Voltage
Threshold Current
and Hysteresis
(M or L Pin)

Line Over-Voltage
or Remote ON/
OFF Threshold
Current and Hys­teresis (M or L Pin)

L Pin Voltage
Threshold

Remote ON/OFF
Negative Threshold
Current and Hyster­esis (M or X Pin)

L or M Pin Short
Circuit Current

X or M Pin Short
Circuit Current

L or M Pin Voltage
(Positive Current)

X Pin Voltage
(Negative Current)

M Pin Voltage
(Negative Current)

Maximum Duty
Cycle Reduction
Onset Threshold
Current

Maximum Duty
Cycle Reduction
Slope

Remote OFF
DRAIN Supply
Current

Threshold

Hysteresis

MULTI-FUNCTION (M), LINE-SENSE (L) AND EXTERNAL CURRENT LIMIT (X) INPUTS

L or M Pin Shorted

to CONTROL

VL, VM = V

C

Normal Mode

Auto-restart Mode

lL or lM = 50 µA

lL or lM = 225 µA

lX = -50 µA

lX = -150 µA

lM = -50 µA

lM = -150 µA

l

UV

I

OV

V

L(TH)

I

REM (N)

IL

(SC)

or

I

M (SC)

IX

(SC)

or

I

M (SC)

VL, V

M

V

X

V

M

I

L (DC)

or

I

M (DC)

I

D(RMT)

VX, VM = 0 V

X, L or M Pin

Floating

TJ = 25 °C

IL > I

L(DC)

or IM > I

M (DC)

See Figure 70
V

DRAIN

= 150 V

TJ = 25 °C

TOP242-249

37

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I

LIMIT

I

INIT

t

LEB

A

A

ns

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V; TJ = -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

CIRCUIT PROTECTION

FREQUENCY INPUT

FREQUENCY Pin
Threshold Voltage

FREQUENCY Pin
Input Current

VF = V

C

V

F

I

F

Self Protection
Current Limit

Initial Current Limit

Leading Edge
Blanking Time

See Note B

2.9 V

10 40 100 µA

MULTI-FUNCTION (M), LINE-SENSE (L) AND CURRENT LIMIT (I) INPUTS (cont)

Remote ON Delay

Remote OFF
Setup Time

t

R(ON)

t

R(OFF)

From Remote On to Drain Turn-On

See Note B

Minimum Time Before Drain Turn-On

to Disable Cycle

See Note B

2.5 µs

2.5 µs

TOP242 P/G
TOP242 Y/R
TJ= 25 °C

TOP243 P/G
TJ= 25 °C

TOP243 Y/R
TJ= 25 °C

TOP244 P/G
TJ= 25 °C

TOP244 Y/R
TJ= 25 °C

TOP245 Y/R
TJ= 25 °C

TOP246 Y/R
TJ= 25 °C

TOP247 Y/R
TJ= 25 °C

TOP248 Y/R
TJ= 25 °C

TOP249 Y/R
TJ= 25 °C

See Fig. 52

TJ = 25 °C

≤ 85 VAC

(Rectified Line Input)

265 VAC

(Rectified Line Input)

IC = 4 mA

Internal; di/dt=90 mA/µs

See Note C

Internal; di/dt=150 mA/µs

See Note C

Internal; di/dt=180 mA/µs

See Note C

Internal; di/dt=200 mA/µs

See Note C

Internal; di/dt=270 mA/µs

See Note C

Internal; di/dt=360 mA/µs

See Note C

Internal; di/dt=540 mA/µs

See Note C

Internal; di/dt=720 mA/µs

See Note C

Internal; di/dt=900 mA/µs

See Note C

Internal;di/dt=1080 mA/µs

See Note C

0.418 0.45 0.481

0.697 0.75 0.802

0.837 0.90 0.963

0.930 1.00 1.070

1.256 1.35 1.445

1.674 1.80 1.926

2.511 2.70 2.889

3.348 3.60 3.852

4.185 4.50 4.815

5.022 5.40 5.778

0.75 x

I

LIMIT(MIN)

0.6 x

I

LIMIT(MIN)

220

See

Note B

TOP242-249

38

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7/01

August 8, 2000

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

J

= -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

OUTPUT

CIRCUIT PROTECTION (cont)

t

IL(D)

V

C(RESET)

100

130 140 150

75

1.75 3.0 4.25

ns

°C

°C

V

Current Limit Delay
Thermal Shutdown

Temperature
Thermal Shutdown

Hysteresis
Power-up Reset

Threshold Voltage

IC = 4 mA

Figure 53, S1 Open

R

DS(ON)

ON-State
Resistance

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TOP242

ID = 50 mA

TOP243

ID = 100 mA

TOP244

ID = 150 mA

TOP245

ID = 200 mA

TOP246

ID = 300 mA

TOP247

ID = 400 mA

TOP248

ID = 500 mA

TOP249

ID = 600 mA

15.6 18.0

25.7 30.0

7.80 9.00

12.9 15.0

5.20 6.00

8.60 10.0

3.90 4.50

6.45 7.50

2.60 3.00

4.30 5.00

1.95 2.25

3.22 3.75

1.56 1.80

2.58 3.00

1.30 1.50

2.15 2.50

Ω

Measured in a Typical

Flyback Converter Application

Off-State
Current

Breakdown
Voltage

Rise
Time

Fall
Time

I

DSS

BV

DSS

t

R

t

F

400 µA

700 V

100 ns

50 ns

VL, VM = Floating; IC = 4mA

VDS = 560 V; TJ = 125 °C

VL, VM = Floating; IC = 4mA

ID = 100 µA; TJ = 25 °C

TOP242-249

39

August 8, 2000

E

7/01

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

J

= -40 to 125 °C

Min Typ Max

Parameter

Symbol

Units

SUPPLY VOLTAGE CHARACTERISTICS

36

5.60 5.85 6.10

±50

1.0 1.6 2.5

1.2 2.2 3.2

0.3 0.6 1.3

V

V

ppm/°C

mA

V

C(SHUNT)

l

CD1

l

CD2

See Note D

IC = 4 mA

Output

MOSFET Disabled

VL, VM = 0 V

NOTES:

A. For specifications with negative values, a negative temperature coefficient corresponds to an increase in

magnitude with increasing temperature, and a positive temperature coefficient corresponds to a decrease in

magnitude with increasing temperature.
B. Guaranteed by characterization. Not tested in production.
C.For externally adjusted current limit values, please refer to Figure 55 (Current Limit vs. External Current Limit

Resistance) in the Typical Performance Characteristics section.
D.It is possible to start up and operate TOPSwitch-GX at DRAIN voltages well below 36 V. However, the

CONTROL pin charging current is reduced, which affects start-up time, auto-restart frequency, and auto-restart

duty cycle. Refer to Figure 67, the characteristic graph on CONTROL pin charge current (IC) vs. DRAIN voltage

for low voltage operation characteristics.

DRAIN Supply
Voltage

Shunt Regulator
Voltage

Shunt Regulator
Temperature Drift

Control Supply/
Discharge Current

Output

MOSFET Enabled

VL, VM = 0 V

TOP 242-245
TOP 246-249

TOP242-249

40

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7/01

August 8, 2000

Figure 51. CONTROL Pin I-V Characteristic.

Figure 50. Duty Cycle Measurement.

Figure 52. Drain Current Operating Envelope.

Figure 53. TOPSwitch-GX General Test Circuit.

PI-2631-033001

5-50 V

5-50 V

S4

40 V

0-15 V

0.1 µF47 µF

470 Ω

5 W

Y or R Package (X and L Pin) P or G Package (M Pin)

470 Ω

0-100 kΩ

0-60 kΩ

0-60 kΩ

0-100 kΩ

NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements.

2. For P and G packages, short all SOURCE pins together.

D

SFX

C

L

M

C

CONTROL

TOPSwitch-GX

S2

S1

S5

S3

PI-2039-033001

DRAIN

VOLTAGE

HV

0 V

90%

10%

90%

t

2

t

1

D =

t

1

t

2

0.8

1.3

1.2

1.1

0.9

0.8

1.0

0

012 6 83

Time (µs)

DRAIN Current (normalized)

PI-2022-033001

45 7

0.7

0.6

0.5

0.4

0.3

0.2

0.1

I

LIMIT(MAX)

@ 25 °C

I

LIMIT(MIN)

@ 25 °C

I

INIT(MIN)

@ 85 VAC

I

INIT(MIN)

@ 265 VAC

t

LEB

(Blanking Time)

120

100

80

40

20

60

0

0246810

CONTROL Pin Voltage (V)

CONTROL Pin Current (mA)

1

Slope

Dynamic

Impedance

=

PI-1939-091996

TOP242-249

41

August 8, 2000

E

7/01

The following precautions should be followed when testing
TOPSwitch-GX by itself outside of a power supply. The
schematic shown in Figure 53 is suggested for laboratory
testing of TOPSwitch-GX.

When the DRAIN pin supply is turned on, the part will be in the
auto-restart mode. The CONTROL pin voltage will be oscillating
at a low frequency between 4.8 and 5.8 V and the drain is turned
on every eighth cycle of the CONTROL pin oscillation. If the
CONTROL pin power supply is turned on while in this auto-

BENCH TEST PRECAUTIONS FOR EVALUATION OF ELECTRICAL CHARACTERISTICS

Typical Performance Characteristics

restart mode, there is only a 12.5% chance that the CONTROL
pin oscillation will be in the correct state (drain active state) so
that the continuous drain voltage waveform may be observed.
It is recommended that the V

C

power supply be turned on first
and the DRAIN pin power supply second if continuous drain
voltage waveforms are to be observed. The 12.5% chance of
being in the correct state is due to the divide-by-8 counter.
Temporarily shorting the CONTROL pin to the SOURCE pin
will reset TOPSwitch-GX, which then will come up in the
correct state.

Figure 54. Current Limit vs. MULTI-FUNCTION Pin Current.

Figure 55. Current Limit vs. External Current Limit Resistance.

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

60
40

80

100

120

140

160

180

200

-250 -200 -150 -100 -50

IM (µA)

Current Limit (A)

di/dt (mA/µs)

PI-2653-033001

0

Scaling Factors:

TOP242: .45
TOP243 P/G: .75
TOP243 Y/R: .90
TOP244 P/G: 1
TOP244 Y/R: 1.35
TOP245 Y/R: 1.80
TOP246 Y/R: 2.70
TOP247 Y/R: 3.60
TOP248 Y/R: 4.50
TOP249 Y/R: 5.40

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

60
40

80

100

120

140

160

180

200

0 5K 10K 15K 20K 25K 30K 35K 40K

External Current Limit Resistor RIL (Ω)

Current Limit (A)

di/dt (mA/µs)

PI-2652-033001

45K

Scaling Factors:

TOP242: .45
TOP243 P/G: .75
TOP243 Y/R: .90
TOP244 P/G: 1
TOP244 Y/R: 1.35
TOP245 Y/R: 1.80
TOP246 Y/R: 2.70
TOP247 Y/R: 3.60
TOP248 Y/R: 4.50
TOP249 Y/R: 5.40

Maximum and minimum levels
are based on characterization.

Minimum

Typical

Maximum

TOP242-249

42

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7/01

August 8, 2000

Typical Performance Characteristics (cont.)

Figure 56. Breakdown Voltage vs. Temperature.

Figure 57. Frequency vs. Temperature.

Figure 58. Internal Current Limit vs. Temperature.

Figure 59. External Current Limit vs. Temperature

with R

IL

=12 kΩ.

Figure 60. Overvoltage Threshold vs. Temperature.

Figure 61. Under-Voltage Threshold vs. Temperature.

1.1

1.0

0.9

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Breakdown Voltage

(Normalized to 25 °C)

PI-176B-033001

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-1123A-033001

Output Frequency

(Normalized to 25 °C)

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2555-033001

Current Limit

(Normalized to 25 °C)

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2554-033001

Current Limit

(Normalized to 25 °C)

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2553-033001

Overvoltage Threshold

(Normalized to 25 °C)

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2552-033001

Under-Voltage Threshold

(Normalized to 25 °C)

TOP242-249

43

August 8, 2000

E

7/01

Typical Performance Characteristics (cont.)

6

5

4

3

2

1

0

-300 -200 -100 0 100 200 300 400 500

PI-2542-102700

MULTI-FUNCTION Pin Voltage (V)

MULTI-FUNCTION Pin Current (µA)

See
Expanded
Version

Figure 63a. MULTI-FUNCTION Pin Voltage vs. Current. Figure 63b. MULTI-FUNCTION Pin Voltage vs.

Current (Expanded).

Figure 64. Control Current Out at 0% Duty Cycle vs.

Temperature.

Figure 65. Max. Duty Cycle Reduction Onset Threshold

Current vs. Temperature.

6.0

4.5

5.5

5.0

2.0
0 100 200 300 400

LINE-SENSE Pin Current (µA)

LINE SENSE Pin Voltage (V)

PI-2688-102700

3.0

2.5

3.5

4.0

Figure 62a. LINE-SENSE Pin Voltage vs. Current.

Figure 62b. EXTERNAL CURRENT LIMIT Pin Voltage

vs. Current.

1.2

1.4

1.6

0.4

0.6

0.2

0.8

1.0

0

-300 -200 -150 -50-250 -100 0

MULTI-FUNCTION Pin Voltage (V)

PI-2541-102700

MULTI-FUNCTION Pin Current (µA)

VM = 1.37 - IMx 1 kΩ

-200 µA

≤

I

M

≤

-25 µA

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2562-033001

CONTROL Current

(Normalized to 25 °C)

1.2

1.0

0.8

0.6

0.4

0.2

0

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

PI-2563-033001

Onset Threshold Current

(Normalized to 25 °C)

1.6

1.0

1.4

1.2

0

-240 -180 -60-120 0

EXTERNAL CURRENT LIMIT Pin Current (µA)

EXTERNAL CURRENT LIMIT

Pin Voltage (V)

PI-2689-102300

0.4

0.2

0.6

0.8

VX = 1.33 - IXx 0.66 kΩ

-200 µA

≤

I

X

≤

-25 µA

TOP242-249

44

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7/01

August 8, 2000

Typical Performance Characteristics (cont.)

0 100 200 300 400 500 600

10

100

1000

10000

PI-2646-033001

Drain Voltage (V)

DRAIN Capacitance (pF)

TOP249 1.00
TOP248 0.83
TOP247 0.67
TOP246 0.50
TOP245 0.33
TOP244 0.25
TOP243 0.17
TOP242 0.08

Scaling Factors:

600

400

500

200

100

300

0

0 200100 400 500300 600

DRAIN Voltage (V)

Power (mW)

PI-2650-033001

TOP249 1.00
TOP248 0.83
TOP247 0.67
TOP246 0.50
TOP245 0.33
TOP244 0.25
TOP243 0.17
TOP242 0.08

Scaling Factors:

Figure 68. C

OSS

vs. DRAIN Voltage.

2

1.2

1.6

0

0 20 40 60 80 100

DRAIN Voltage (V)

CONTROL Pin

Charging Current (mA)

IC vs. DRAIN VOLTAGE

PI-2564-101499

0.4

0.8

VC = 5 V

Figure 66. Output Characteristics.

1.2

0.8

1.0

0

-50 0 50 100 150

Junction Temperature (°C)

Remote OFF DRAIN Supply Current

(Normalized to 25 °C)

PI-2690-102700

0.2

0.4

0.6

Figure 70. Remote OFF DRAIN Supply Current

vs. Temperature.

6

5

0

02468101214161820

DRAIN Voltage (V)

DRAIN Current (A)

PI-2645-033001

2

1

T

CASE

= 25 °C

T

CASE

= 100 °C

4

3

TOP249 1.00
TOP248 0.83
TOP247 0.67
TOP246 0.50
TOP245 0.33
TOP244 0.25
TOP243 0.17
TOP242 0.08

Scaling Factors:

Figure 67. IC vs. DRAIN Voltage.

Figure 69. DRAIN Capacitance Power.

TOP242-249

45

August 8, 2000

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7/01

PI-2644-040501

Notes:

1. Controlling dimensions are inches. Millimeter
dimensions are shown in parentheses.

2. Pin numbers start with Pin 1, and continue
from left to right when viewed from the front.

3. Dimensions do not include mold flash or
other protrusions. Mold flash or protrusions
shall not exceed .006 (.15mm) on any side.

4. Minimum metal to metal spacing at the pack­ age body for omitted pin locations is .068
inch (1.73 mm).

5. Position of terminals to be measured at a
location .25 (6.35) below the package body.

6. All terminals are solder plated.

Y07C

PIN 1

PIN 7

MOUNTING HOLE PATTERN

.050 (1.27)

.150 (3.81)

.050 (1.27)

.150 (3.81)

.050 (1.27)

.050 (1.27)

.100 (2.54)

.180 (4.58)

.200 (5.08)

PIN 1

+

.010 (.25) M

.467 (11.86)
.487 (12.37)

.400 (10.16)
.415 (10.54)

.146 (3.71)
.156 (3.96)

.860 (21.84)
.880 (22.35)

.026 (.66)
.032 (.81)

.050 (1.27) BSC

.150 (3.81) BSC

.108 (2.74) REF

PIN 1 & 7

7° TYP.

PIN 2 & 4

.040 (1.02)
.060 (1.52)

.190 (4.83)
.210 (5.33)

.015 (.38)
.020 (.51)

.095 (2.41)
.115 (2.92)

.236 (5.99)
.260 (6.60)

.165 (4.19)
.185 (4.70)

.040 (1.02)
.060 (1.52)

.045 (1.14)
.055 (1.40)

.670 (17.02)
REF.

.570 (14.48)
REF.

TO-220-7C

TOPSwitch Product Family
GX Series Number
Package Identifier

G Plastic Surface Mount DIP

P Plastic DIP
Y Plastic TO-220-7C
R Plastic TO-263-7C (available only with TL option)

Package/Lead Options

Blank Standard Configurations

TL Tape & Reel, (G Package: 1 k min., R Package: 750 min.)

PART ORDERING INFORMATION

TOP 242 G - TL

(242, 243 & 244 only)

TOP242-249

46

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7/01

August 8, 2000

SMD-8B

PI-2546-040501

.004 (.10)
.012 (.30)

.036 (0.91)
.044 (1.12)

.004 (.10)

0 -

°

8

°

.375 (9.53)
.385 (9.78)

.048 (1.22)

.009 (.23)

.053 (1.35)

.032 (.81)
.037 (.94)

.128 (3.25)
.132 (3.35)

-D-

Notes:

1. Controlling dimensions are
inches. Millimeter sizes are
shown in parentheses.

2. Dimensions shown do not
include mold flash or other
protrusions. Mold flash or
protrusions shall not exceed
.006 (.15) on any side.

3. Pin locations start with Pin 1,
and continue counter-clock
Pin 8 when viewed from the
top. Pin 6 is omitted.

4. Minimum metal to metal
spacing at the package body
for the omitted lead location
is .137 inch (3.48 mm).

5. Lead width measured at
package body.

6. D and E are referenced
datums on the package
body.

.057 (1.45)
.063 (1.60)

(NOTE 5)

E S

.100 (2.54) (BSC)

.372 (9.45)

.245 (6.22)

.388 (9.86)

.255 (6.48)

.010 (.25)

-E-

Pin 1

D S

.004 (.10)

⊕

⊕

G08B

Heat Sink is 2 oz. Copper

As Big As Possible

.420

.046

.060

.060

.046

.080

Pin 1

.086

.186

.286

Solder Pad Dimensions

Notes:

1. Package dimensions conform to JEDEC specification
MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP)
package with .300 inch row spacing.

2. Controlling dimensions are inches. Millimeter sizes are
shown in parentheses.

3. Dimensions shown do not include mold flash or other
protrusions. Mold flash or protrusions shall not exceed
.006 (.15) on any side.

4. Pin locations start with Pin 1, and continue counter-clock­ wise to Pin 8 when viewed from the top. The notch and/or
dimple are aids in locating Pin 1. Pin 6 is omitted.

5. Minimum metal to metal spacing at the package body for
the omitted lead location is .137 inch (3.48 mm).

6. Lead width measured at package body.

7. Lead spacing measured with the leads constrained to be
perpendicular to plane T.

.010 (.25)
.015 (.38)

.300 (7.62) BSC

(NOTE 7)

.300 (7.62)
.390 (9.91)

.375 (9.53)
.385 (9.78)

.245 (6.22)
.255 (6.48)

.128 (3.25)
.132 (3.35)

.057 (1.45)
.063 (1.60)

.125 (3.18)
.135 (3.43)

0.15 (.38)

MINIMUM

.048 (1.22)
.053 (1.35)

.100 (2.54) BSC

.014 (.36)
.022 (.56)

-E-

Pin 1

SEATING
PLANE

-D-

-T-

P08B

DIP-8B

PI-2551-101599

D S

.004 (.10)

⊕

T E D S

.010 (.25) M

⊕

(NOTE 6)

TOP242-249

47

August 8, 2000

E

7/01

.165 (4.19)
.185 (4.70)

R07C

TO-263-7C

PI-2664-040501

-A-

LD #1

.580 (14.73)
.620 (15.75)

.396 (10.06)
.415 (10.54)

.326 (8.28)
.336 (8.53)

.055 (1.40)
.066 (1.68)

.100 (2.54)

Ref.

.208 (5.28)

Ref.

.026 (0.66)
.032 (0.81)

.225 (5.72)

min.

.245 (6.22)

min.

.000 (0.00)
.010 (0.25)

.010 (0.25)

.090 (2.29)
.110 (2.79)

.017 (0.43)
.023 (0.58)

°

8 -

°

0

.045 (1.14)
.055 (1.40)

.050 (1.27)

Notes:

1. Package Outline Exclusive of Mold Flash & Metal Burr.

2. Package Outline Inclusive of Plating Thickness.

3. Foot Length Measured at Intercept Point Between
Datum A Lead Surface.

4. Controlling Dimensions are in Inches. Millimeter
Dimensions are shown in Parentheses.

.004 (0.10)

.315 (8.00)

.128 (3.25)

.038 (0.97)

.050 (1.27)

.380 (9.65)

.638 (16.21)

Solder Pad
Dimensions

TOP242-249

48

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7/01

August 8, 2000

Notes

-

1) Added R package (D2PAK).

2) Corrected abbreviations (s = seconds).

3) Corrected x-axis units in Figure 11 (µA).

4) Added missing external current limit resistor in Figure 25 (RIL).

5) Corrected spelling.

6) Added caption for Table 4.

7) Corrected Breakdown Voltage parameter condition (TJ = 25 °C)

8) Corrected font sizes in figures.

9) Figure 40 replaced.

10) Corrected schematic component values in Figure 44.

Date

11/00

7/01

Revision

D

E

KOREA

Power Integrations
International Holdings, Inc.
Rm# 402, Handuk Building
649-4 Yeoksam-Dong,
Kangnam-Gu,
Seoul, Korea
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

WORLD HEADQUARTERS
AMERICAS

Power Integrations, Inc.
5245 Hellyer Avenue
San Jose, CA 95138 USA
Main: [phone]
Customer Service:
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

For the latest updates, visit our Web site: www.powerint.com
Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability.
Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it
convey any license under its patent rights or the rights of others.

The PI Logo,

TOPSwitch, TinySwitch

and

EcoSmart

are registered trademarks of Power Integrations, Inc.

©Copyright 2001, Power Integrations, Inc.

JAPAN

Power Integrations, K.K.
Keihin-Tatemono 1st Bldg.
12-20 Shin-Yokohama 2-Chome
Kohoku-ku, Yokohama-shi
Kanagawa 222-0033, Japan
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

TAIWAN

Power Integrations
International Holdings, Inc.
17F-3, No. 510
Chung Hsiao E. Rd.,
Sec. 5,
Taipei, Taiwan 110, R.O.C.
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

EUROPE & AFRICA

Power Integrations (Europe) Ltd.
Centennial Court
Easthampstead Road
Bracknell
Berkshire, RG12 1YQ
United Kingdom
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

CHINA

Power Integrations
International Holdings, Inc.
Rm# 1705, Bao Hua Bldg.
1016 Hua Qiang Bei Lu
Shenzhen, Guangdong 518031
China
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

INDIA (Technical Support)

Innovatech
#1, 8th Main Road
Vasanthnagar
Bangalore, India 560052
Phone: [phone]
Fax: [phone]

e-mail: [e-mail]

APPLICATIONS HOTLINE

World Wide [phone]

APPLICATIONS FAX

World Wide [phone]