Datasheet MC34163DWR2, MC34163P, MC33163P, MC33163DW, MC34163DW Datasheet (Motorola)

  

The MC34163 series are monolithic power switching regulators that
contain the primary functions required for dc–to–dc converters. This series is
specifically designed to be incorporated in step–up, step–down, and
voltage–inverting applications with a minimum number of external
components.

These devices consist of two high gain voltage feedback comparators,
temperature compensated reference, controlled duty cycle oscillator, driver
with bootstrap capability for increased efficiency, and a high current output
switch. Protective features consist of cycle–by–cycle current limiting, and
internal thermal shutdown. Also included is a low voltage indicator output
designed to interface with microprocessor based systems.

These devices are contained in a 16 pin dual–in–line heat tab plastic
package for improved thermal conduction.

• Output Switch Current in Excess of 3.0 A

• Operation from 2.5 V to 40 V Input

• Low Standby Current

• Precision 2% Reference

• Controlled Duty Cycle Oscillator

• Driver with Bootstrap Capability for Increased Efficiency

• Cycle–by–Cycle Current Limiting

• Internal Thermal Shutdown Protection

• Low Voltage Indicator Output for Direct Microprocessor Interface

• Heat Tab Power Package

Order this document by MC34163/D




POWER SWITCHING

REGULATORS

SEMICONDUCTOR

TECHNICAL DATA

16

1

P SUFFIX

PLASTIC PACKAGE

CASE 648C

(DIP–16)

16

1

DW SUFFIX

PLASTIC PACKAGE

CASE 751G

(SOP–16L)

Ipk Sense

V

CC

Timing

Capacitor

Gnd

Voltage

Feedback 1

Voltage

Feedback 2

LVI Output

Representative Block Diagram

8

7

6

5

4

3

2

1

OSC

LVI

+
+
–

This device contains 114 active transistors.

I

–

Limit

+

+

Control Logic

and Thermal

Shutdown

VFB

+
+
–

(Bottom View)

+

+

9

10

11

12

13

14

15

16

Driver
Collector

Switch
Collector

Gnd

Switch
Emitter

Bootstrap
Input

PIN CONNECTIONS

LVI Output
Voltage Feedback 2
Voltage Feedback 1

Gnd

Timing Capacitor

V

CC

Ipk Sense

ORDERING INFORMATION

Device

MC34163DW
MC34163P
MC33163DW
MC33163P

Temperature Range

TA = – 40° to +85°C

116
2
3
4
5
6
7
8

(Top View)

Operating

TA = 0° to +70°C

Bootstrap Input

15

Switch
Emitter

14
13

Gnd

12
11

Switch Collector

10

Driver Collector

9

SOP–16L

SOP–16L

Package

DIP–16

DIP–16

MOTOROLA ANALOG IC DEVICE DATA

 Motorola, Inc. 1996 Rev 2

1

MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply Voltage V
Switch Collector Voltage Range V
Switch Emitter Voltage Range V
Switch Collector to Emitter Voltage V
Switch Current (Note 1) I
Driver Collector Voltage V
Driver Collector Current I
Bootstrap Input Current Range (Note 1) I
Current Sense Input Voltage Range V
Feedback and Timing Capacitor Input

Voltage Range

Low Voltage Indicator Output Voltage

Range

Low Voltage Indicator Output Sink Current I

Thermal Characteristics

P Suffix, Dual–In–Line Case 648C

Thermal Resistance, Junction–to–Air
Thermal Resistance, Junction–to–Case

(Pins 4, 5, 12, 13)

DW Suffix, Surface Mount Case 751G

Thermal Resistance, Junction–to–Air
Thermal Resistance, Junction–to–Case

(Pins 4, 5, 12, 13)

Operating Junction Temperature T

Operating Ambient Temperature (Note 3)

MC34163
MC33163

Storage Temperature Range T

CE(switch)

Ipk (Sense)(VCC

MC34163 MC33163

CC
C(switch)
E(switch)

SW

C(driver)

C(driver)

BS

V

in

V

C(LVI)

C(LVI)

R

θJA

R

θJC

R

θJA

R

θJC

J

T

A

stg

–1.0 to + 40 V

– 2.0 to V

–1.0 to +40 V

–100 to +100 mA

–7.0) to (VCC+1.0) V

–1.0 to + 7.0 V

–1.0 to + 40 V

0 to +70

– 40 to + 85

– 65 to +150 °C

40 V

C(switch)

40 V

3.4 A

150 mA

10 mA

°C/W

80
15

94
18

+150 °C

°C

V

ELECTRICAL CHARACTERISTICS (V

the operating ambient temperature range that applies (Note 3), unless otherwise noted.)

Characteristic

OSCILLAT OR

Frequency

TA = 25°C

Total Variation over VCC = 2.5 V to 40 V, and Temperature
Charge Current I
Discharge Current I
Charge to Discharge Current Ratio I
Sawtooth Peak Voltage V
Sawtooth Valley Voltage V

FEEDBACK COMPARATOR 1

Threshold Voltage

TA = 25°C

Line Regulation (VCC = 2.5 V to 40 V, TA = 25°C)

Total Variation over Line, and Temperature
Input Bias Current (V

NOTES: 1. Maximum package power dissipation limits must be observed.

2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.

3.T

=0

low

=–40°C for MC33163 = + 85°C for MC33163

= 5.05 V) I

FB1

°C for MC34163 T

= 15 V, Pin 16 = VCC, CT = 620 pF, for typical values TA = 25°C, for min/max values TA is

CC

Symbol Min Typ Max Unit

f

OSC

chg

dischg

chg/Idischg

OSC(P)
OSC(V)

V

th(FB1)

IB(FB1)

=+70°C for MC34163

high

46
45

– 225 – µA
– 25 – µA

8.0 9.0 10 –
– 1.25 – V
– 0.55 – V

4.9
–

4.85
– 100 200 µA

50

–

5.05

0.008
–

54
55

5.2

0.03

5.25

kHz

V

%/V

V

2

MOTOROLA ANALOG IC DEVICE DATA

MC34163 MC33163

ELECTRICAL CHARACTERISTICS (continued) (V

values TA is the operating ambient temperature range that applies (Note 3), unless otherwise noted.)

Characteristic Symbol Min Typ Max Unit

FEEDBACK COMPARATOR 2

Threshold Voltage

TA = 25°C
Line Regulation (VCC = 2.5 V to 40 V, TA = 25°C)
Total Variation over Line, and Temperature

Input Bias Current (V

CURRENT LIMIT COMPARATOR

Threshold Voltage

TA = 25°C
Total Variation over VCC = 2.5 V to 40 V, and Temperature

Input Bias Current (V

DRIVER AND OUTPUT SWITCH (Note 2)

Sink Saturation Voltage (ISW = 2.5 A, Pins 14, 15 grounded)

Non–Darlington Connection (R

Darlington Connection (Pins 9, 10, 11 connected)
Collector Off–State Leakage Current (VCE = 40 V) I
Bootstrap Input Current Source (VBS = VCC + 5.0 V) I
Bootstrap Input Zener Clamp Voltage (IZ = 25 mA) V

LOW VOLTAGE INDICATOR

Input Threshold (V
Input Hysteresis (V
Output Sink Saturation Voltage (I
Output Off–State Leakage Current (VOH = 15 V) I

TOTAL DEVICE

Standby Supply Current (VCC = 2.5 V to 40 V, Pin 8 = VCC,

Pins 6, 14, 15 = Gnd, remaining pins open)

NOTES: 1. Maximum package power dissipation limits must be observed.

2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.

3.T

=0°C for MC34163 T

low

=–40°C for MC33163 = + 85°C for MC33163

= 1.25 V) I

FB2

Ipk (Sense)

Increasing) V

FB2

Decreasing) V

FB2

= 15 V) I

= 110 Ω to VCC, ISW/I

Pin 9

= 2.0 mA) V

sink

=+70°C for MC34163

high

= 15 V, Pin 16 = VCC, CT = 620 pF, for typical values TA = 25°C, for min/max

CC

V

DRV

≈ 20)

th(FB2)

IB(FB2)

V

th(Ipk Sense)

IB(sense)

V

CE(sat)

C(off)

source(DRV)

Z

th

H

OL(LVI)

OH

I

CC

1.225

1.213
– 0.4 0 0.4 µA

230

0.5 2.0 4.0 mA

VCC + 6.0 VCC + 7.0 VCC + 9.0 V

1.07 1.125 1.18 V

–

–

– 1.0 20 µA

–
–

– 0.02 100 µA

– 15 – mV
– 0.15 0.4 V
– 0.01 5.0 µA

– 6.0 10 mA

1.25

0.008
–

250

–

0.6

1.0

1.275

0.03

1.287

–

270

1.0

1.4

V

%/V

V

mV

V

Figure 1. Output Switch On–Off Time

µ

100

10

, OUTPUT SWITCH ON–OFF TIME ( s)t

off

–t

on

1.0

0.1

versus Oscillator Timing Capacitor

VCC = 15 V

°

C

TA = 25

1) ton, RDT =

2) ton, RDT = 20 k

3) ton, t

4) t

off

5) t

off

∞

, RDT = 10 k

off

, RDT = 20 k

∞

, RDT =

CT, OSCILLAT OR TIMING CAPACITOR (nF)

1

2
3

4
5

1.0 10

MOTOROLA ANALOG IC DEVICE DATA

2.0

0

– 2.0

– 4.0

, OSCILLAT OR FREQUENCY CHANGE (%)

OSC

– 6.0

f

–55

∆

Figure 2. Oscillator Frequency Change

versus T emperature

VCC = 15 V

CT = 620 pF

– 25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

°

C)

3

MC34163 MC33163

Figure 3. Feedback Comparator 1 Input Bias

Current versus Temperature

140

µ

120

100

80

, INPUT BIAS CURRENT ( A)

IB

I

60

–55

– 25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

VCC = 15 V
V

= 5.05 V

FB1

°

C)

Figure 5. Bootstrap Input Current

Source versus T emperature

2.8
VCC = 15 V

2.4

Pin 16 = VCC + 5.0 V

Figure 4. Feedback Comparator 2 Threshold

V oltage versus Temperature

1300

1280

1260

1240

1220

, COMPARATOR 2 THRESHOLD VOLTAGE (mV)

1200

th(FB2)

VCC = 15 V

–55

– 25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

Vth Max = 1275 mV

Vth Typ = 1250 mV

Vth Min = 1225 mV

Figure 6. Bootstrap Input Zener Clamp

V oltage versus Temperature

7.6
IZ = 25 mA

7.4

°

C)

2.0

1.6

, BOOTSTRAP INPUT CURRENT SOURCE (mA)

1.2
– 55 – 25 0 25 50 75 100 125

source (DRV)

I

TA, AMBIENT TEMPERATURE (

°

C)

Figure 7. Output Switch Source Saturation

versus Emitter Current

0

V

CC

– 0.4

– 0.8

Bootstrapped, Pin 16 = VCC + 5.0 V

–1.2

, SOURCE SATURATION (V)

–1.6

CE (sat)

V

Non–Bootstrapped, Pin 16 = V

– 2.0

0 0.8 2.4 3.2

IE, EMITTER CURRENT (A)

Darlington Configuration

Emitter Sourcing Current to Gnd

Pins 7, 8, 10, 11 = V
Pins 4, 5, 12, 13 = Gnd

°

C, (Note 2)

TA = 25

CC

1.6

CC

7.2

7.0

6.8

, BOOTSTRAP INPUT ZENER CLAMP VOLTAGE (V)

– 55 – 25 0 25 50 75 100 125

Z

V

TA, AMBIENT TEMPERATURE (

°

C)

Figure 8. Output Switch Sink Saturation

versus Collector Current

1.2
Darlington, Pins 9, 10, 11 Connected

1.0

0.8

Grounded Emitter Configuration

Collector Sinking Current From V

0.6

Pins 7, 8 = VCC = 15 V

, SINK SATURATION (V) V

CE (sat)

V

Pins 4, 5, 12, 13, 14, 15 = Gnd

0.4

0.2

0

0 0.8 2.4 3.21.6

TA = 25

°

C, (Note 2)

IC, COLLECTOR CURRENT (A)

CC

Saturated Switch, R

Gnd

Pin9

= 110 Ω to V

CC

4

MOTOROLA ANALOG IC DEVICE DATA

MC34163 MC33163

Figure 9. Output Switch Negative Emitter

V oltage versus Temperature

0

Gnd

– 0.4

– 0.8

– 1.2

, EMITTER VOLTAGE (V)

E

V

– 1.6

– 2.0

– 55 – 25 0 25 50 75 100 125

IC = 10 µA

IC = 10 mA

VCC = 15 V

Pins 7, 8, 9, 10, 16 = V

Pins 4, 6 = Gnd
Pin 14 Driven Negative

TA, AMBIENT TEMPERATURE (°C)

Figure 11. Current Limit Comparator Threshold

V oltage versus Temperature

254

VCC = 15 V

252

CC

Figure 10. Low V oltage Indicator Output Sink

Saturation V oltage versus Sink Current

0.5
VCC=5 V

°

C

TA=25

0.4

0.3

0.2

, OUTPUT SA TURATION VOLTAGE (V)

0.1

OL (LVI)

0

V

0 2.0 4.0 6.0 8.0

I

, OUTPUT SINK CURRENT (mA)

sink

Figure 12. Current Limit Comparator Input Bias

Current versus Temperature

1.6

µ

1.4

VCC = 15 V
V

Ipk (Sense)

= 15 V

250

, THRESHOLD VOLTAGE (mV)

248

th (Ipk Sense)

V

246

– 55 – 25 0 25 50 75 100 125

°

TA, AMBIENT TEMPERATURE (

C)

Figure 13. Standby Supply Current

versus Supply V oltage

8.0

6.0

4.0

, SUPPLY CURRENT (mA)

2.0

CC

I

0

0 10203040

V

, SUPPLY VOLTAGE (V)

CC

Pins 7, 8, 16 = V

Pins 4, 6, 14 = Gnd

Remaining Pins Open

TA = 25

CC

°

C

1.2

1.0

INPUT BIAS CURRENT ( A)

,

0.8

IB (Sense)

I

0.6

– 55 – 25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

°

C)

Figure 14. Standby Supply Current

versus T emperature

7.2

VCC = 15 V

Pins 7, 8, 16 = V

6.4

5.6

, SUPPLY CURRENT (mA)

4.8

CC

I

4.0

– 55 – 25 0 25 50 75 100 125

TA, AMBIENT TEMPERATURE (

Pins 4, 6, 14 = Gnd
Remaining Pins Open

°

CC

C)

MOTOROLA ANALOG IC DEVICE DATA

5

3.0

ÎÎÎ

2.6

2.2

MC34163 MC33163

Figure 15. Minimum Operating Supply

V oltage versus Temperature

CT = 620 pF

Pin 16 Open

Pins 7,8 = V
Pins 4, 14 = Gnd

Pin 9 = 1.0 k

Pin 10 = 100

CC

Ω

to 15 V

Ω

to 15 V

Figure 16. P Suffix (DIP–16) Thermal Resistance

and Maximum Power Dissipation

versus P.C.B. Copper Length

°

100

80

60

R

θ

JA

Printed circuit board heatsink example

2.0 oz

L

Copper

L

Graphs represent symmetrical layout

3.0 mm

5.0

4.0

3.0

1.8
Pin 16 = V

CC

1.4

, MINIMUM OPERATING SUPPLY VOLTAGE (V)

1.0

– 55 – 25 0 25 50 75 100 125

CC(min)

V

TA, AMBIENT TEMPERATURE (

°

C)

Figure 17. DW Suffix (SOP–16L) Thermal Resistance and

Maximum Power Dissipation versus P.C.B. Copper Length

100

90
80

°

70
60
50

JA

θ

JUNCTION–TO–AIR ( C/W)

R , THERMAL RESISTANCE

40
30

02030504010

R

40

JA

20

θ

JUNCTION–TO–AIR ( C/W)

R , THERMAL RESISTANCE

0

0

P

for TA = 50°C

D(max)

Graph represents symmetrical layout

2.0 oz.

L

Copper

θ

JA

L, LENGTH OF COPPER (mm)

P

for TA = 70°C

D(max)

10 20 30 40 50

L, LENGTH OF COPPER (mm)

2.8

2.4

2.0

1.6

1.2

3.0 mmL

0.8

0.4
0

, MAXIMUM POWER DISSIPATION (W)

D

P

2.0

1.0

0

, MAXIMUM POWER DISSIPATION (W)

D

P

6

MOTOROLA ANALOG IC DEVICE DATA

MC34163 MC33163

Figure 18. Representative Block Diagram

Shutdown

Comparator Output

1.25 V

Timing Capacitor C

T

0.55 V

Oscillator Output

On

Output Switch

Off

Nominal Output

Voltage Level

Ipk

Sense

R

SC

V

CC

Timing Capacitor

C

T

R

DT

Gnd

Voltage Feedback 1

Voltage Feedback 2

LVI Output

1

0

1

0

8

7

6

5

4

3

0.25 V

+

Oscillator

–

+

+

Thermal

Current

Limit

+

R

Q

S

Latch

9

10

11

Q

1

Q

2

12

60

13

14

45 k

Feedback

+
+

–

+
+
–

+

+

1.125 V

Comparator

15 k1.25 V

+

7.0 V

2

1

LVI

2.0 mA

15

16

(Bottom View)

Figure 19. T ypical Operating Waveforms

t

9t

Driver Collector

Switch Collector

Gnd

Switch Emitter

Bootstrap Input

+
–

Sink Only

=

Positive True Logic

Output Voltage

MOTOROLA ANALOG IC DEVICE DATA

Startup Quiescent Operation

7

MC34163 MC33163

INTRODUCTION

The MC34163 series are monolithic power switching
regulators optimized for dc–to–dc converter applications. The
combination of features in this series enables the system
designer to directly implement step–up, step–down, and
voltage–inverting converters with a minimum number of
external components. Potential applications include cost
sensitive consumer products as well as equipment for
the automotive, computer, and industrial markets. A
Representative Block Diagram is shown in Figure 18.

OPERA TING DESCRIPTION

The MC34163 operates as a fixed on–time, variable
off–time voltage mode ripple regulator. In general, this mode
of operation is somewhat analogous to a capacitor charge
pump and does not require dominant pole loop
compensation for converter stability. The Typical Operating
Waveforms are shown in Figure 19. The output voltage
waveform shown is for a step–down converter with the ripple
and phasing exaggerated for clarity. During initial converter
startup, the feedback comparator senses that the output
voltage level is below nominal. This causes the output switch
to turn on and off at a frequency and duty cycle controlled by
the oscillator, thus pumping up the output filter capacitor.
When the output voltage level reaches nominal, the feedback
comparator sets the latch, immediately terminating switch
conduction. The feedback comparator will inhibit the switch
until the load current causes the output voltage to fall below
nominal. Under these conditions, output switch conduction
can be inhibited for a partial oscillator cycle, a partial cycle
plus a complete cycle, multiple cycles, or a partial cycle plus
multiple cycles.

Oscillator

The oscillator frequency and on–time of the output switch
are programmed by the value selected for timing capacitor
CT. Capacitor CT is charged and discharged by a 9 to 1 ratio
internal current source and sink, generating a negative going
sawtooth waveform at Pin 6. As CT charges, an internal pulse
is generated at the oscillator output. This pulse is connected
to the NOR gate center input, preventing output switch
conduction, and to the AND gate upper input, allowing the
latch to be reset if the comparator output is low. Thus, the
output switch is always disabled during ramp–up and can be
enabled by the comparator output only at the start of
ramp–down. The oscillator peak and valley thresholds are

1.25 V and 0.55 V, respectively, with a charge current of
225 µA and a discharge current of 25 µA, yielding a maximum
on–time duty cycle of 90%. A reduction of the maximum duty
cycle may be required for specific converter configurations.
This can be accomplished with the addition of an external
deadtime resistor (RDT) placed across CT. The resistor
increases the discharge current which reduces the on–time
of the output switch. A graph of the Output Switch On–Off
Time versus Oscillator T iming Capacitance for various values
of RDT is shown in Figure 1. Note that the maximum output
duty cycle, ton/ton + t
greater than 0.2 nF. The converter output can be inhibited by

, remains constant for values of C

off

clamping CT to ground with an external NPN small–signal
transistor.

Feedback and Low Voltage Indicator Comparators

Output voltage control is established by the Feedback
comparator. The inverting input is internally biased at 1.25 V
and is not pinned out. The converter output voltage is
typically divided down with two external resistors and
monitored by the high impedance noninverting input at Pin 2.
The maximum input bias current is ±0.4 µA, which can cause
an output voltage error that is equal to the product of the input
bias current and the upper divider resistance value. For
applications that require 5.0 V, the converter output can be
directly connected to the noninverting input at Pin 3. The high
impedance input, Pin 2, must be grounded to prevent noise
pickup. The internal resistor divider is set for a nominal
voltage of 5.05 V. The additional 50 mV compensates for a

1.0% voltage drop in the cable and connector from the
converter output to the load. The Feedback comparator’s
output state is controlled by the highest voltage applied to
either of the two noninverting inputs.

The Low Voltage Indicator (L VI) comparator is designed for
use as a reset controller in microprocessor–based systems.
The inverting input is internally biased at 1.125 V, which sets
the noninverting input thresholds to 90% of nominal. The L VI
comparator has 15 mV of hysteresis to prevent erratic reset
operation. The Open Collector output is capable of sinking in
excess of 6.0 mA (see Figure 10). An external resistor (R
and capacitor (C
time (t
microprocessor reset input threshold. Refer to Figure 20.

Current Limit Comparator,
Latch and Thermal Shutdown

With a voltage mode ripple converter operating under
normal conditions, output switch conduction is initiated by the
oscillator and terminated by the Voltage Feedback
comparator. Abnormal operating conditions occur when the
converter output is overloaded or when feedback voltage
sensing is lost. Under these conditions, the Current Limit
comparator will protect the Output Switch.

The switch current is converted to a voltage by inserting a
fractional ohm resistor, RSC, in series with VCC and output
switch transistor Q2. The voltage drop across RSC is
monitored by the Current Sense comparator. If the voltage
drop exceeds 250 mV with respect to VCC, the comparator
will set the latch and terminate output switch conduction on a
cycle–by–cycle basis. This Comparator/Latch configuration
ensures that the Output Switch has only a single on–time
during a given oscillator cycle. The calculation for a value of
RSC is:

T

) by the formula shown below, where V

DLY

t

= R

DLY

) can be used to program a reset delay

DLY

1

V

LVI CDLY

RSC+

In

I

pk(Switch)

1 –

0.25

th(MPU)

V

out

V

th(MPU)

Ǔǒ

LVI

is the

)

8

MOTOROLA ANALOG IC DEVICE DATA

MC34163 MC33163

Figures 11 and 12 show that the Current Sense
comparator threshold is tightly controlled over temperature
and has a typical input bias current of 1.0 µA. The
propagation delay from the comparator input to the Output
Switch is typically 200 ns. The parasitic inductance
associated with RSC and the circuit layout should be
minimized. This will prevent unwanted voltage spikes that
may falsely trip the Current Limit comparator.

Internal thermal shutdown circuitry is provided to protect
the IC in the event that the maximum junction temperature is
exceeded. When activated, typically at 170°C, the Latch is
forced into the “Set” state, disabling the Output Switch. This
feature is provided to prevent catastrophic failures from
accidental device overheating. It is not intended to be used
as a replacement for proper heatsinking.

Driver and Output Switch

To aid in system design flexibility and conversion
efficiency, the driver current source and collector, and output
switch collector and emitter are pinned out separately. This
allows the designer the option of driving the output switch into
saturation with a selected force gain or driving it near
saturation when connected as a Darlington. The output
switch has a typical current gain of 70 at 2.5 A and is
designed to switch a maximum of 40 V collector to emitter,
with up to 3.4 A peak collector current. The minimum value for
RSC is:

V

R

SC(min)

When configured for step–down or voltage–inverting
applications, as in Figures 20 and 24, the inductor will forward
bias the output rectifier when the switch turns off. Rectifiers
with a high forward voltage drop or long turn–on delay time
should not be used. If the emitter is allowed to go sufficiently
negative, collector current will flow, causing additional device
heating and reduced conversion efficiency.

Figure 9 shows that by clamping the emitter to 0.5 V, the
collector current will be in the range 10 µA over temperature.
A 1N5822 or equivalent Schottky barrier rectifier is
recommended to fulfill these requirements.

A bootstrap input is provided to reduce the output switch
saturation voltage in step–down and voltage–inverting

+

0.25

3.4

A

+

0.0735 Ω

converter applications. This input is connected through a
series resistor and capacitor to the switch emitter and is used
to raise the internal 2.0 mA bias current source above VCC.
An internal zener limits the bootstrap input voltage to V
+7.0 V. The capacitor’s equivalent series resistance must
limit the zener current to less than 100 mA. An additional
series resistor may be required when using tantalum or other
low ESR capacitors. The equation below is used to calculate
a minimum value bootstrap capacitor based on a minimum
zener voltage and an upper limit current source.

C

B(min)

Parametric operation of the MC34163 is guaranteed over
a supply voltage range of 2.5 V to 40 V. When operating
below 3.0 V , the Bootstrap Input should be connected to VCC.
Figure 15 shows that functional operation down to 1.7 V at
room temperature is possible.

Package

The MC34163 is contained in a heatsinkable 16–lead
plastic dual–in–line package in which the die is mounted on a
special heat tab copper alloy lead frame. This tab consists of
the four center ground pins that are specifically designed to
improve thermal conduction from the die to the circuit board.
Figures 16 and 17 show a simple and effective method of
utilizing the printed circuit board medium as a heat dissipater
by soldering these pins to an adequate area of copper foil.
This permits the use of standard layout and mounting
practices while having the ability to halve the junction–to–air
thermal resistance. These examples are for a symmetrical
layout on a single–sided board with two ounce per square
foot of copper.

+

∆t

I

+

4.0

∆V

mA

t

on

4.0

+

0.001

V

CC

t

on

APPLICATIONS

The following converter applications show the simplicity
and flexibility of this circuit architecture. Three main converter
topologies are demonstrated with actual test data shown
below each of the circuit diagrams.

MOTOROLA ANALOG IC DEVICE DATA

9

MC34163 MC33163

Figure 20. Step–Down Converter

–

+

+

Thermal

Current

Limit

+

R

Q

S

Latch

9

10

11

Q

1

Q

2

12

60

13

14

V

in

12 V

R

SC

0.075
C

in

330

C

T

680 pF

0.25 V

8

7

+

+

6

Oscillator

5

4

3

45 k

+

Low Voltage

Indicator Output

R

LVI

10 k

C

DLY

2

1

LVI

+

+
+
–

+
–

+

1.125 V

Feedback
Comparator

15 k1.25 V

+

2.0 mA

7.0 V

(Bottom View)

15

16

1N5822

0.02

C

B

R

B

2200

Test Condition Results

Line Regulation Vin = 8.0 V to 24 V, IO = 3.0 A 6.0 mV = ± 0.06%
Load Regulation Vin = 12 V, IO = 0.6 A to 3.0 A 2.0 mV = ± 0.02%
Output Ripple Vin = 12 V, IO = 3.0 A 36 mVpp
Short Circuit Current Vin = 12 V, RL = 0.1 Ω 3.3 A
Efficiency , Without Bootstrap Vin = 12 V, IO = 3.0 A 76.7%
Efficiency, With Bootstrap Vin = 12 V, IO = 3.0 A 81.2%

180 µH
Coilcraft LO451–A

L

+

C

O

V

out

5.05 V/3.0 A

10

Figure 21. External Current Boost Connections for Ipk

(Switch)

Greater Than 3.4 A

Figure 21A. External NPN Switch Figure 21B. External PNP Saturated Switch

8

7

+

6

5

4

+

3

2

1

9

10

11

Q

1

Q

2

12

13
14

Q

3

15

16

+

(Bottom View)

8

7

+

6

5

4

+

3

2

1

9

10

11

Q

1

Q

2

12

13
14

15

16

+

(Bottom View)

MOTOROLA ANALOG IC DEVICE DATA

Q

3

V

in

12 V

Low Voltage

Indicator

Output

2.2 k

R

0.075

680 pF

R

1

SC

C

330

C

in

T

R

1.0 k

MC34163 MC33163

Figure 22. Step–Up Converter

+

Thermal

45 k

+

+
+
–

Current

Limit

–
+

+
+
–

+

1.125 V

(Bottom View)

+

Feedback
Comparator

15 k1.25 V

LVI

+

47 k

R

8

7

6

5

4

3

2

1

2

0.25 V

+

Oscillator

LVI

R

Q

S

Latch

+

Q

1

60

2.0 mA

7.0 V

180 µH
Coilcraft

L

9

LO451–A

10

11

Q

2

12

13

1N5822

14

15

16

V

+

C

O

out

28 V/600 mA

330

Test Condition Results

Line Regulation Vin = 9.0 V to 16 V, IO = 0.6 A 30 mV = ± 0.05%
Load Regulation Vin = 12 V, IO = 0.1 A to 0.6 A 50 mV = ± 0.09%
Output Ripple Vin = 12 V, IO = 0.6 A 140 mVpp
Efficiency Vin = 12 V, IO = 0.6 A 88.1%

Figure 23. External Current Boost Connections for Ipk

(Switch)

Greater Than 3.4 A

Figure 23A. External NPN Switch Figure 23B. External PNP Saturated Switch

8

7

+

6

5

4

+

3

2

1

+

(Bottom View)

9

10

11

Q

1

Q

2

12

13
14

Q

3

15

16

8

7

+

6

5

4

+

3

2

1

9

10

11

Q

1

Q

2

12

13
14

Q3

15

16

+

(Bottom View)

MOTOROLA ANALOG IC DEVICE DATA

11

MC34163 MC33163

Figure 24. V oltage–Inverting Converter

–

+

+

Thermal

45 k

+

+
+

+

–

Current

Limit

+
+
–

1.125 V

(Bottom View)

R

Q

S

Latch

+

Feedback
Comparator

15 k1.25 V

+

Q

1

60

2.0 mA

7.0 V

9

10

11

Q

2

12

13

Coilcraft LO451–A

14

15

0.02

16

180

R
C

L

µ

H

B
B

1N5822

C

2200

O

+

V

in

12 V

C

470 pF

T

R

SC

0.075
C

in

330

R

2

8.2 k

+

8

7

6

5

4

3

2

1

R

953

0.25 V

+

Oscillator

LVI

1

Test Condition Results

Line Regulation Vin = 9.0 V to 16 V, IO = 1.0 A 5.0 mV = ± 0.02%
Load Regulation Vin = 12 V, IO = 0.6 A to 1.0 A 2.0 mV = ± 0.01%
Output Ripple Vin = 12 V, IO = 1.0 A 130 mVpp
Short Circuit Current Vin = 12 V, RL = 0.1 Ω 3.2 A
Efficiency , Without Bootstrap Vin = 12 V, IO = 1.0 A 73.1%
Efficiency, With Bootstrap Vin = 12 V, IO = 1.0 A 77.5%

V

out

– 12 V/1.0 A

12

Figure 25. External Current Boost Connections for Ipk

(Switch)

Greater Than 3.4 A

Figure 25A. External NPN Switch Figure 25B. External PNP Saturated Switch

8

7

+

6

5

4

+

3

2

1

+

(Bottom View)

9

10

11

Q

1

Q

2

12

13
14

15

Q

3

16

8

7

+

6

5

4

+

3

2

1

9

10

11

Q

1

Q

2

12

13
14

15

16

+

(Bottom View)

MOTOROLA ANALOG IC DEVICE DATA

Q

3

MC34163 MC33163

Figure 26. Printed Circuit Board and Component Layout

(Circuits of Figures 20, 22, 24)

+

+

+

+

V

in

+–

in

C

MC34163 Step–Down

+

++

+

2

R

R

1

R

T

C

R

SC

Bottom View Top View

++

+

+

2

R

–

R

1

R

T

C

R

SC

MC34163 Step–Up

V

in

+

in

C

+

++

+

LVI

LVI

V

O

V

O

–

B

C

–

+

O

C

B

R

C

+

L

+

+

O

+

L

+

MC34163 Voltage–Inverting

+

Bottom View Top View

++

+

+

V

in

+

–

in

C

+

+

V

O

+

2

R

T

C

R

R

SC

B

1

C

Bottom View Top View

All printed circuit boards are 2.58” in width by 1.9” in height.

+

–

O

C

B

R

+

L

+

MOTOROLA ANALOG IC DEVICE DATA

13

MC34163 MC33163

Figure 27. Design Equations

Calculation Step–Down Step–Up V oltage–Inverting

t

on

t

off

(Notes 1, 2, 3)

t

on

C

T

V

out

Vin*

t

ǒ

ƒ

t

32.143 · 10

on
off

)

V

F

V

*

V

t
t

sat

on
off

out

Ǔ

)

1

–6

ƒ

V

)

out

Vin–V

t

ǒ

ƒ

t

32.143 · 10

VF–V

sat

t

on

t

off

on

)

off

ƒ

1

–6

in

Ǔ

|V

|)V

out

Vin*

V

t

on

t

off

t

on

ǒ

ƒ

32.143 · 10

)

t

off

ƒ

sat

–6

F

Ǔ

1

I

L(avg)

I

pk (Switch)

R

SC

Vin*

L

V

ripple(pp)

V

out

The following Converter Characteristics must be chosen:

Nominal operating input voltage.

Vin –

Desired output voltage.

V

–

out

Desired output current.

I

–

out

Desired peak–to–peak inductor ripple current. For maximum output current it is suggested that

∆I

–

L

than 10% of the average inductor current I

set by RSC. If the design goal is to use a minimum inductance value, let
converter output current capability.
Maximum output switch frequency.

p

–

V

ripple(pp)

Desired peak–to–peak output ripple voltage. For best performance the ripple voltage should be kept to a low value since

–

it will directly affect line and load regulation. Capacitor CO should be a low equivalent series resistance (ESR) electrolytic
designed for switching regulator applications.

ǒ

D

I

L

I

L(avg)

I

pk (Switch)

V

sat

D

1

ǒ

8C

ƒ

ǒ

V

ref

I

out

0.25

I

L

O

R
R

)

*

2

Ǔ

2
1

D

V

)

)

I

L

2

out

(ESR)

1

Ǔ

t

on

2

Ǔ

L(avg)

t

on

ǒ

I

out

t

off

I

)

L(avg)

0.25

I

pk (Switch)

Vin*

ref

V

D

I

L

tonI

[

C

R

2

ǒ

R

1

ǒ

V

. This will help prevent Ipk

)

D

2

sat

Ǔ

out

O

)

(Switch)

∆I

Ǔ

1

I

L

t

on

Ǔ

1

from reaching the current limit threshold

= 2(I

L

L(avg)

∆I

). This will proportionally reduce

ǒ

I

out

I

L(avg)

I

pk (Switch)

Vin*

ǒ

D

[

V

ref

be chosen to be less

L

ǒ

t

on

t

off

0.25

V

I

L

tonI

C

R

2

R

1

)

sat

Ǔ

)

1

D

I

L

2

Ǔ

t

on

out

O

Ǔ

)

1

NOTES: 1. V

NOTES: 2. VF – Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.5 V.
NOTES: 3. The calculated ton/t
NOTES: 3. operating input voltage.

14

– Saturation voltage of the output switch, refer to Figures 7 and 8.

sat

must not exceed the minimum guaranteed oscillator charge to discharge ratio of 8, at the minimum

off

MOTOROLA ANALOG IC DEVICE DATA

MC34163 MC33163

OUTLINE DIMENSIONS

P SUFFIX

PLASTIC PACKAGE

CASE 648C–03

(DIP–16)

–T–

SEATING
PLANE

–A–

916

–B–

18

NOTE 5

C

N

K

F

D

0.13 (0.005) T A

G

16 PL

E

M

S

PLASTIC PACKAGE

CASE 751G–02

–A–

916

–B–

P 8 PL

18

0.25 (0.010)

G 14 PL

M M

J

F

C

–T–

16 PL

D

0.25 (0.010) T A B

K

M

SEATING
PLANE

S S

M

L

J

0.13 (0.005) T B

DW SUFFIX

(SOP–16L)

B

R

16 PL

X 45°

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.

4. DIMENSION B DOES NOT INCLUDE MOLD
FLASH.

5. INTERNAL LEAD CONNECTION, BETWEEN 4
AND 5, 12 AND 13.

INCHES

MIN MINMAX MAX

DIM

0.740

A

0.240

B

0.145

C

0.015

D
E

M

M

S

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSIONS A AND B DO NOT INCLUDE MOLD
PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER
SIDE.

5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.13 (0.005) TOTAL IN
EXCESS OF D DIMENSION AT MAXIMUM
MATERIAL CONDITION.

DIM

A
B
C
D
F

G

J
K

M

P
R

0.050 BSC

0.040

F

0.100 BSC

G
J

0.008

K

0.115

0.300 BSC

L
M

0

°

N

0.015

MILLIMETERS INCHES

MIN MINMAX MAX

10.45

10.15

7.60

7.40

2.65

2.35

0.49

0.35

0.90

0.50

1.27 BSC 0.050 BSC

0.32

0.25

0.25

0.10
7

0

°

°

10.05

10.55

0.25

0.75

0.840

0.260

0.185

0.021

0.070

0.015

0.135
10

0.040

0.400

0.292

0.093

0.014

0.020

0.010

0.004
0

0.395

0.010

MILLIMETERS

18.80

6.10

3.69

0.38

1.02

0.20

2.92

°

0.39

0.411

0.299

0.104

0.019

0.035

0.012

0.009

°

0.415

0.029

1.27 BSC

2.54 BSC

7.62 BSC

0

°

7

°

21.34

6.60

4.69

0.53

1.78

0.38

3.43
10

°

1.01

MOTOROLA ANALOG IC DEVICE DATA

15

MC34163 MC33163

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty , representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation consequential or incidental damages. “T ypical” parameters which may be provided in Motorola
data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”
must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of
others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other
applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury
or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola
and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees
arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola
was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal
Opportunity/Affirmative Action Employer.

How to reach us:
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16

– US & Canada ONLY 1–800–774–1848 51 Ting Kok Road, T ai Po, N.T., Hong Kong. 852–26629298

◊

MOTOROLA ANALOG IC DEVICE DATA

Mfax is a trademark of Motorola, Inc.

MC34163/D