ST L4963, L4963D User Manual

L4963

®

1.5A OUTPUT LOAD CURRENT

5.1 TO 36V OUTPUT VOLTAGE RANGE
DISCONTINUOUS VARIABLE FREQUENCY
MODE
PRECISE (+/–2%) ON CHIP REFERENCE
VERY HIGH EFFICIENC Y
VERY FEW EXTERNAL COMPONENTS
NO FREQ. COMPENSATION REQUIRED
RESET AND POWER FAIL OUTPUT FOR MI­CROPROC ESSOR
INTERNAL CURRENT LIMITING
THERMAL SHUTDOWN

DESCRIPTION

The L4 963 is a m onolith ic power switching r e gulator
delivering 1.5A at 5.1 V. The output v o l t ag e is a dj ust­able from 5.1V to 36V, working in discontinuous
variable frequency mode. Features of the device
include re mote inhibit, internal curr ent limiting and
thermal protecti on, reset and power fail outp uts for
microprocessor.

L4963D

1.5A SWITCHING REGULATOR

Powerdip12+3+3

ORDERING NUMBERS:

L4963W L4963D

The L4963 is mounted in a 12+3+3 lead Powerdip
(L4963) and SO20 large (L4963D) plastic pack­ages and requires very few external components.

SO20

BLOCK DIAGRAM

June 2000

1/17

This is a dvanced i nformation on a new product now in development or und ero gi n evaluat i on . Details ar e s u bj ect to ch ange with ou t notice.

L4963 - L4963D

ABSOLUTE MAXIMUM RATINGS

Symbol

SO20 Powerdip

V

i

V

3–V2

V

2

V

2

V

8

, V

V

9

11

V

10

, V

V

13

18

, V

V

19

20

V8, V

V12, V
V17, V

P

tot

T

, T

stg

j

P

tot

PIN CONNECTION

V

7

10

V

9

16

18

(top view)

Parameter Value Unit

Input Voltage (pin 1 and pin 3 connected togheter)
Input to Output Voltage Difference
Negative Output DC Voltage
Negative Output Peak Voltage at t=0.2 µs, f=50kHz
Power Fail Input
Reset and Power Fail Output
Reset Delay Input
Feedback and Inhibit Inputs
Oscillator Inputs
Total Power Dissipation Tpins ≤ 90°C (Power DIP)

(T

= 70°C no copper area on PCB)

amb

= 70°C, 4cm2 copper area on PCB)

(T

amb

Storage & Junction Temperature
(Tamb = 70°C 6cm2 copper area on PCB)

Total Power Dissipation Tpins ≤90°C (SO20L)

47 V
47 V
–1 V
–5 V
25 V

V

i

5.5 V
7V

5.5 V
5

1.3
2

–40 to 150

1.45

W
W
W

C

°

W

4W

Powerdip18

SO20

2/17

PIN FUNCTIONS

SO20L Power DIP Name Description

L4963 - L4963D

11
22

33

4, 5, 6, 7

14, 15, 16, 17

4, 5, 6

13, 14, 15

87

98

10 9

11 10

12 11

13 12

18 16

SIGNAL SUPPLY VOLTAGE Must be Connected to pin 3
OUTPUT Regulator output

SUPPLY VOLTAGE

Unregulated voltage input. An internal regulator
powers the internal logic.

GROUND Common ground terminal

Input of the power fail circuit. The threshold can be

POWER FAIL INPUT

modified introducing an external voltage divider
between the Supply Voltage and GND.

POWER FAIL OUTPUT

RESET DELAY

RESET OUTPUT

Open collector power fail signal output. This output
is high when the supply voltage is safe.

A capacitor connected between this terminal and
ground determines the reset signal delay time.

Open collector reset signal output. This output is
high when the output voltage value is correct.

REFERENCE VOLTAGE Reference voltage output.

Feedback terminal of the regulation loop.

FEEDBACK INPUT

The output is connected directly to this terminal for

5.1V operation; it is connected via a divider for
higher voltages.

INHIBIT INPUT

TTL level remote inhibit. A logic low level on this
input disables the device.

19 17

C OSCILLATOR

between this terminal and ground modifies the
maximum oscillator frequency.

Oscillator waveform. A capacitor connected

20 18

R OSCILLATOR FREQ.

A resistor connected between this terminal and
ground defines the maximum switching frequency.

THERMAL DATA

Symbol Parameter SO20 Powerdip Unit

R

th j-pins

R

th j-amb

(*) See Fig. 28

Thermal Resistance Junction to Pins max.
Thermal Resistance Junction to Ambient (*) max.

15 12
85 80

C/W

°

C/W

°

3/17

L4963 - L4963D

CIRCUIT DESCRIPTION (Refer to Block Dia­gram)

The L4963 is a monolithic stepdown regulator pro­viding 1.5A at 5.1V working in discontinuous vari­able frequency mode. In normal operation the
device resonates at a frequency depending primar­ily on the inductance value, the input and output
voltage and the load current. The maximum switch­ing however can be limited by an internal oscillator ,
which can be programmed by only one external
resistor.

The fondamental regulation loop consists of two
comparators, a precision 5.1V on-chip reference
and a drive latch. Briefly the operation is as follows:
when the choke ends its discharge the catch free­wheeling recirculation filter diode begins to come
out of forward conduction so the output voltage of
the device approaches ground. When the output
voltage reaches –0.1V the internal comparator sets
the latch and the power stage is turned on. Then
the inductor current rises linearly until the voltage
sensed at the feedback input reaches the 5.1V
reference.

The second comparator then resets the latch and
the output stage is turned off. The current in the
choke falls linearly until it is fully discharged, then
the cycle repeats. Closing the loop directly gives an
output voltage of 5.1V. Higher output voltages are

obtained by inserting a voltage divider and this
method of control requires no frequency compen­sation network. At output voltages greater than

5.1V the available output current must be derated
due to the increased power dis sipation of the de­vice.

Output overload protection is provided by an inter­nal current limiter. The load current is sensed by a
on-chip metal resistor connected to a comparator
which resets the latch and turns off the power stage
in overload condition. The reset circuits (s ee fig. 1)
generates an output high signal when the output
voltage value is correct. It has an open collector
output and the output signal delay time can be
programmed with an external capacitor. A power­fail circuit is also available and is used to monitor
the supply voltage. Its out put goes h igh when the
supply voltage reaches a pre-programmed tres hold
set by a voltage divider to its input from the supply
to ground. With the input left open the threshold is
approximately equal to 5.1V. The output of the
power fail is an open collector.

A T TL level inhibit is provided for applications suc h
as remote on/off control. This input is activated by
a low logic level and disables circuits operation.

The thermal overload circuit disables the device
when the junction temperature is about 150°C and
has hysteresis to prevent unstable conditions.

Figure 1:

Reset and Power Fail Function

4/17

L4963 - L4963D

ELECTRICAL CHARACTERISTIC

(Refer to the te s t ci r cui t V

= 30V T

i

=

25°C unless oth erw is e spe cif ied )

j

Symbol Parameter Test Conditions Min. Typ. Max. Unit Fig.

DYNAMIC CHARACTERISTICS

V

o

V

i

V

12

I

12

V

OS12

V

∆

o

V

∆

o

V

d

I

2L

I

o

SVR

V

11

V

∆

11

V

∆

11

η

T

sd

Output Voltage Range Vi = 46V Io = 0.5A
Input Voltage Range Vo = V

to 36V Io = 0.5A 9 46 V 2

ref

Feedback Voltage Vi = 9 to 46V Io = 0.5A 5 5.1 5.2 V 2
Input Bias Current

Vi = 15V V12 = 6V
V

= 5V

17f

Input Offset Voltage
Line Regulation

Load Regulation
Dropout Voltage Between

pin 3 and pin 2
Current Limiting
Maximum Operating Load

Current
Supply Voltage Ripple

Rejection
Reference Voltage
Average Temperature

Coefficient of Ref. Volt.
V

Line Regulation Vi = 9 to 46V

ref

V

Line Regulation

ref

Efficiency I

Vi = 9 to 46V Vo = V
Io = 0.5A

Vo = V
Io = 0.5 to 1.5A

I2 = 3A

= 20V

V

i

Vi = 9 to 46V

= V

V

o

Vi = 9 to 46V Vo = V
V

= 2Vrms Vo = V

i

fripple = 100Hz Io = 1.5A
Vi = 9 to 46V

O < I11 < 5mA
T

= 0 to 125 °C

j

I

= 0 to 5mA

ref

Vi = 46V R

= 1.5A Vo = V

o

ref

to 28V

ref

osc

= 51K

ref

ref

ref

ref

Ω

Thermal Shutdown
Junction Temperature

Hysteresis

V

ref

520

36 V 2

A3a

µ

510mV3a

15 50 mV 2

15 45 mV 2

1.5 2 V 2

3.5 6.5 A 2

1.5 A 2

50 56 dB 2

5 5.1 5.2 V 3a

0.4 mV/°C–
10 20 mV 3a

65
69

715mV3a

65 75 % 2

145 150

30

C–

°

C–

°

DC CHARACTERISTICS

I

q

Quescent Drain Current

INHIBIT

V

16L

V

16H

I

16L

I

16L

Low Input Voltage Vi = 9 to 46V
High Input Voltage Vi = 9 to 46V
Input Current with Low

Input Voltage
Input Current with High

Input Voltage

Vi = 46V
Io = 0mA

V16 = 0.8V

V16 = 2V

V

= V12 = 0 14 20 mA 3a

16

= V

V

16

V12 = 5.3V

ref

11 16 mA 3a

0.3 0.8 V 2

25.5V2
50 100

10 20

A2

µ

A2

µ

5/17

L4963 - L4963D

ELECTRICAL CHARACTERISTIC

(Continued)

Symbol Parameter Test Conditions Min. Typ. Max. Unit Fig.

RESET

V

12

V

12

V

9D

V

9F

–I

9SO

I

9SI

I

10

V

10

Rising Threshold Voltage Vi = 9 to 46V

Falling Threshold Voltage Vi = 9 to 46V
Delay Rising Thereshold

Voltage

V7 = OPEN

Delay Falling Thereshold
Voltage

Delay Source Current V9 = 4.7V V12 = 5.3V

V

–150

V

–150

4.3 4.5 4.7 V 3b

11.52 V3b

70 110 140
Delay Sink Current V9 = 4.7V V12 = 4.7V 10 mA 3b
Output Leakage Current Vi = 46V V7 = 8.5V

50
Output Saturation Volt. I10 = 15mA; VI = 3 to 46V

V

ref

–100

V

ref

–200

V

ref

ref

ref

–50
V

ref

–250

mV 3b

mV 3b

A3b

µ

A3b

µ

0.4 V 3b

POWER FAIL

V

R

V

F

V

7

V

7

V

s

I

s

Rising Threshold Voltage Pin7 = open
Falling Threshold Voltage Pin7 = open
Rising Threshold Voltage Vi = 20V
Falling Threshold Voltage Vi = 20V
Output Saturation Volt. Ia = 5mA
Output Leakage Current Vi = 46V

17.5 19 20.5 V 3C

14.25 15 15.75 V 3c

4.14 4.5 4.86 V –

3.325 3.5 3.675 V –

0.4 V 3c
50

A3c

µ

OSCILLATOR

f

f

Oscillator Frequency R

Oscillator Frequency

= 51K

Ω

T

= 9 to 46V

V

I

Tj = 0 to 125°C
RT = 51K

Ω

46 60 79 kHz –

42 83 kHz –

6/17