Datasheet L4962A, L4962EH-A, L4962E-A Datasheet (SGS Thomson Microelectronics)



1.5APOWER SWITCHING REGULATOR

1.5AOUTPUTCURRENT

5.1V TO40V OUTPUTVOLTAGE RANGE
PRECISE(±2%) ON-CHIPREFERENCE
HIGH SWITCHING FREQUENCY
VERYHIGH EFFICIENCY (UP TO 90%)
VERYFEW EXTERNALCOMPONENTS
SOFT START
INTERNALLIMITINGCURRENT
THERMALSHUTDOWN

DESCRIPTION

TheL4962 is a monolithicpower switching regula­tor delivering1.5Aat a voltage variable from 5V to
40V in step down configuration.

Featuresofthe device includecurrentlimiting,soft
start,thermal protectionand 0 to 100% dutycycle
for continuousoperatingmode.

L4962

POWERDIP

(12 + 2 + 2)

ORDERING NUMBERS

: L4962/A(12 + 2 + 2 Powerdip)

L4962E/A (Heptawatt
L4962EH/A (Horizontal

TheL4962ismountedin a16-leadPowerdipplastic
packageand Heptawattpackageand requiresvery
few externalcomponents.

Efficient operation at switching frequencies up to
150KHz allows a reduction in the size and cost of
external filtercomponents.

HEPTAWATT

Vertical)

Heptawatt)

BLOCKDIAGRAM

June 2000

Pin X = Powerdip
Pin (X) = Heptawatt

1/16

L4962

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

Input voltage 50 V

7

Input to output voltage difference 50 V
Negative output DC voltage -1 V

2

V

7-V2

V

V

Output peakvoltage at t = 0.1µs; f= 100KHz -5 V

V

11,V15

V

P

T

j,Tstg

I
I

Voltageat pin11,15 5.5 V
Voltageat pin10 7 V

10

Pin 11 sink current 1 mA

11

Pin 14 source current 20 mA

14

Power dissipationat T

tot

Junction and storage temperature -40 to150

PIN CONNECTION (Top view)

C (Powerdip)

≤90°

pins

T

≤ 90°C (Heptawatt)

case

4.3
15

W
W

C

°

THERMALDATA

Symbol Parameter Heptawatt Powerdip

R

thj-case

R

thj-pins

R

thj-amb

* Obtained with the GND pins soldered to printed circuit with minimized copperarea.

Thermal resistance junction-case max 4°C/W ­Thermal resistance junction-pins max - 14°C/W
Thermal resistance junction-ambient max 50°C/W 80°C/W*

PIN FUNCTIONS

HEPTAWATT POWERDIP NAME

1 7 SUPPLYVOLTAGE Unregulatedvoltage input. Aninternalregulatorpowers

the internal logic.

2 10 FEEDBACK INPUT Thefeedback terminal of theregulation loop.Theoutput

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

3 11 FREQUENCY

COMPENSATION

A series RC network connected between this terminal
and ground determines the regulation loop gain
characteristics.

2/16

FUNCTION

PIN FUNCTIONS (cont’d)

L4962

HEPTAWATT POWERDIP NAME

FUNCTION

4 4, 5, 12, 13 GROUND Common ground terminal.

5 14 OSCILLATOR A parallel RC network connected to this terminal

determines the switching frequency. This pin must be
connected to pin 7 input when the internal oscillator is
used.

6 15 SOFT START Soft start time constant. A capacitor is connected

between this terminaland ground to definethe softstart
time constant. This capacitor also determines the
average short circuit output current.

7 2 OUTPUT Regulator output.

1, 3, 6,

N.C.

8, 9, 16

ELECTRICAL CHARACTERISTICS

(Refer to the test circuit, T

=25°C, Vi= 35V, unless otherwise

j

specified)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

DYNAMICCHARACTERISTICS

V

Output voltage range Vi= 46V Io=1A V

o

V

Input voltage range Vo=V

i

∆ V
∆

V

Line regulation Vi= 10V to 40V Vo=V

o

V

Load regulation Vo=V

o

Internal reference voltage

ref

(pin 10)

V

∆

∆

I

I

Average temperature

ref

coefficient of refer. voltage

T

V

Dropout voltage Io= 1.5A 1.5 2 V

d

Maximum operatingload

om

current

I

Current limiting threshold

2L

(pin 2)
Input average current Vi= 46V; outputshort-circuit 15 30 mA

SH

Efficiency f = 100KHz V

η

SVR Supply voltage ripple

rejection

ref

to 36V Io= 1.5A 9 46 V

ref

=1A 15 50 mV

refIo

ref

Io= 0.5A to 1.5A 8 20 mV

40 V

Vi= 9V to 46V Io= 1A 5 5.1 5.2 V

T

=0°C to125°C

j

=1A

I

o

Vi= 9V to 46V
V

o=Vref

to 36V

1.5 A

Vi= 9V to 46V
V

I

o

∆

fripple

V

to 36V

o=Vref

o=Vref

=1A Vo= 12V 80 %

V

=2V

i

rms

50 56 dB

= 100Hz

o=Vref

Io = 1A

0.4 mV/°C

2 3.3 A

70 %

3/16

L4962

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

DYNAMICCHARACTERISTICS

(cont’d)

f Switching frequency 85 100 115 KHz

f

∆

Voltagestability of

∆ V

∆

f

switching frequency

i

∆ f

Temperature stabilityof
switching frequency

T

j

Maximum operating

max

Vi= 9V to 46V 0.5 %

Tj=0°C to 125°C1%

Vo=V

ref

Io= 1A 120 150 KHz

switching frequency

T

Thermal shutdown

sd

150 °C

junction temperature

DC CHARACTERISTICS

I

Quiescent draincurrent 100% duty cycle

7Q

pins 2 and 14 open

V

= 46V

i

0% dutycycle 15 20 mA

30 40 mA

-I

Output leakagecurrent 0% duty cycle 1 mA

2L

SOFT START

I

15SO

I

Source current 100 140 180
Sink current 50 70 120 µA

15SI

ERRORAMPLIFIER

V
V
I

-I

High level output voltage V10= 4.7V I11= 100µA 3.5 V

11H

Low level output voltage V10= 5.3V I11= 100µA 0.5 V

11L

Sink output current V10= 5.3V 100 150

11SI

Source outputcurrent V10= 4.7V 100 150 µA

11SO

I

Input bias current V10= 5.2V 2 10

10

DC open loop gain V11=1Vto3V 46 55 dB

G

v

OSCILLATOR

-I

Oscillator source current 5 mA

14

A

µ

A

µ

A

µ

4/16

L4962

CIRCUITOPERATION

(refertothe blockdiagram)

TheL4962is amonolithicstepdownswitchingregu­latorprovidingoutputvoltagesfrom5.1Vto40Vand
delivering 1.5A.

The regulationloop consists of a sawtoothoscilla­tor, error amplifier, comparator and the output
stage.An errorsignalisproducedbycomparingthe
output voltage with a precise 5.1V on-chip refer­ence (zener zaptrimmedto±2%).

Thiserrorsignalis thencomparedwiththesawtooth
signal to generate the fixed frequencypulse width
modulated pulseswhich drivethe output stage.

The gain andfrequencystabilityof the loop can be
adjusted by an external RC network connectedto
pin 11. Closing the loop directly gives an output
voltage of 5.1V. Higher voltages are obtained by
insertinga voltagedivider.

Output overcurrentsat switchon are prevented by
the softstart function.The erroramplifieroutput is
initially clamped by the external capacitor C

and

ss

Figure1. Softstart waveforms

allowedtorise,linearly,asthiscapacitoris charged
by aconstantcurrentsource.Outputoverloadpro­tection is provided in the form of a current limiter.
The load current is sensed by an internal metal
resistorconnectedtoa comparator.When the load
currentexceedsapresetthresholdthis comparator
sets a flipflop whichdisables the output stage and
dischargesthe soft start capacitor.Asecondcom­parator resets the flipflopwhen thevoltageacross
the soft start capacitorhas fallento 0.4V.

The output stage is thusre-enabledandthe output
voltagerisesunder controlof the soft start network.
If the overload condition is still present the limiter
will trigger again when the threshold current is
reached.Theaverageshortcircuitcurrentislimited
to a safevalueby the dead timeintroduced by the
soft start network. The thermaloverload circuit dis­ables circuit operation when the junctiontempera­ture reaches about 150°C and has hysteresis to
preventunstable conditions.

Figure2. Currentlimiterwaveforms

5/16

L4962

Figure3. Testandapplicationcircuit (Powerdip)

1) D1: BYW98 or 3ASchottky diode, 45V ofVRRM;
: CORE TYPE - MAGNETICS 58120 - A2 MPP

2) L

1

N°TURNS 45, WIRE GAUGE: 0.8mm (20 AWG)

3) C

: ROE, EKR 220µF 40V

6,C7

Figure 4. Quiescent drain
currentvs. supplyvoltage (0%
duty cycle)

6/16

Figure 5. Quiesc ent drain
current vs. supply v olta ge
(100% duty cycle)

Figure 6. Quiescent drain
current vs. junction tem­perature(0%duty cycle)

L4962

Figure 7. Quiescent drain
current vs. junction tem­perature (100%duty cycle)

Figure 10. Open loop fre­quency and phase re- sponse
of error amplifier

Figure 8. Reference voltage
(pin 10) vs. V

rdip) vs. V

i

i

Figure 11. Sw itching fre­quency vs. inputvoltage

Figure 9. Reference voltage
(pin 10 ) vs. junction tem­perature

Figure 1 2. Switching fre­qu en cy vs . junc ti o n tem­perature

Figure 13. Switching fre­quencyvs. R2 (seetestcircuit)

Figure 14. Line transient
response

Figu re 15. Load transi ent
response

7/16

L4962

Figure 16. Supply voltage
ripplerejectionvs. frequency

Figure 19. Effici ency vs.
output current

Figure 17. Dropout voltage
between pin 7 and pin 2 vs.
currentat pin 2

Figure 20. Effici ency vs.
output current

Figure 1 8. Dropout voltage
betweenpin7and2vs.
junction temperature

Figure 21. Efficiency vs.
output current

Figure 22. E fficiency vs.
output voltage

8/16

Figure 23. Effici ency vs.
output voltage

Figure 24. Maximum allow­ablepowerdissipationvs. am­bient temperature(Powerdip)

APPLICATION INFORMATION

Figure25. Typicalapplication circuit

C1,C6,C7: EKR(ROE)

: BYW98 OR VISK340 (SCHOTTKY)

D

1

SUGGESTED INDUCTORS: (L
COGEMA 946043
OR U15,GUP15, 60 TURNS 1mm, AIRGAP 0.8mm (20 AWG)-COGEMA969051.

) = MAGNETICS 58120 - A2MPP - 45TURNS - WIRE GAUGE 0.8mm (20AWG)

1

L4962

Figure26. P.C. board andcomponent layout of the circuit of Fig.25 (1 : 1 scale)

Resistor values for

standard output 7 voltages

V

12V
15V
18V
24V

o

R3 R4

4.7KΩ

4.7K

Ω

4.7K

Ω

4.7K

Ω

6.2KΩ

9.1K
12K
18K

Ω
Ω
Ω

9/16

L4962

APPLICATION INFORMATION

(continued)

Figure27. - A minimal 5.1V fixedregulator;Veryfewcomponent are required

* COGEMA946043 (TOROID CORE)
** EKR (ROE)

969051 (U15 CORE)

Figure28. Programmablepower supply

Vo= 5.1V to15V
I

= 1.5A max

o

Load regulation (0.5Ato 1.5A) = 10mV (V
Line regulation(220V±15% and to I

= 5.1V)

o

= 1A) = 15mV (Vo= 5.1V)

o

10/16

L4962

APPLICATION INFORMATION

(continued)

Figure29. DC-DC converter5.1V/4A,± 12V/1A.A suggestionhow to synchronizea negativeoutput

L1, L3 = COGEMA946043 (969051)
L2 =COGEMA 946044 (946045)

Figure30. In multiplesupplies several
L4962s can be synchronizedas shown

Figure 31. Preregulatorfor distributedsupplies

* L2 and C2 are necessary to reduce the switching frequency spikes

when linear regulators are remote from L4962

11/16

L4962

MOUNTINGINSTRUCTION

The Rth-j-amb of the L4962 can be reduced by
solderingtheGNDpinsto a suitablecopperareaof
the printed circuit board (Fig. 32).
The diagram of figure 33 shows the R

th-j-amb

function of the side ”l” of two equal square copper
areashavingthethicknessof 35µ(1.4mils).During

as a

soldering the pins temperature must not exceed
260°C and the soldering time must not be longer
than 12 seconds.
The external heatsink or printed circuit copper are
must be connectedto electricalground.

Figure32.Exampleof P.C.boardcopperareawhichisused
as heatsink

Figure 33. Maximum dissipable
power and junction to ambient
thermalresistancevs. side ”l”

12/16

L4962

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

a1 0.51 0.020

B 0.85 1.40 0.033 0.055

b 0.50 0.020

b1 0.38 0.50 0.015 0.020

D 20.0 0.787

E 8.80 0.346

e 2.54 0.100

e3 17.78 0.700

F 7.10 0.280

I 5.10 0.201

L 3.30 0.130

Z 1.27 0.050

mm inch

OUTLINE AND

MECHANICAL DATA

Powerdip 16

13/16

L4962

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 4.8 0.189
C 1.37 0.054
D 2.4 2.8 0.094 0.110

D1 1.2 1.35 0.047 0.053

E 0.35 0.55 0.014 0.022

E1 0.7 0.97 0.028 0.038

F 0.6 0.8 0.024 0.031

F1 0.9 0.035

G 2.34 2.54 2.74 0.095 0.100 0.105
G1 4.88 5.08 5.28 0.193 0.200 0.205
G2 7.42 7.62 7.82 0.295 0.300 0.307
H2 10.4 0.409
H3 10.05 10.4 0.396 0.409

L 16.7 16.9 17.1 0.657 0.668 0.673
L1 14.92
L2 21.24 21.54 21.84 0.386 0.848 0.860
L3 22.27 22.52 22.77 0.877 0.891 0.896
L4 1.29
L5 2.6 2.8 3 0.102 0.110 0.118
L6 15.1 15.5 15.8 0.594 0.610 0.622
L7 6 6.35 6.6 0.236 0.250
L9 0.2 0.008

M 2.55 2.8 3.05 0.100 0.110 0.120

M1 4.83 5.08 5.33 0.190 0.200 0.210

V4 40° (typ.)

Dia 3.65 3.85 0.144 0.152

mm inch

0.587

0.051

0.260

OUTLINE AND

MECHANICAL DATA

Heptawatt V

H3

L

VV

E

L1

M1

A

C

D

M

D1

H2

V4

L9

H1

L5

Dia.

L2
L3

F

E1

E

GG1G2

F

L7

L4

L6

F1H2

HEPTAMEC

14/16

L4962

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 4.8 0.189
C 1.37 0.054
D 2.4 2.8 0.094 0.110

D1 1.2 1.35 0.047 0.053

E 0.35 0.55 0.014 0.022
F 0.6 0.8 0.024 0.031

F1 0.9 0.035

G 2.41 2.54 2.67 0.095 0.100 0.105
G1 4.91 5.08 5.21 0.193 0.200
G2 7.49 7.62 7.8 0.295 0.300 0.307
H2 10.4 0.409
H3 10.05 10.4 0.396 0.409

L 14.2 0.559
L1 4.4
L2 15.8
L3 5.1
L5 2.6 3 0.102 0.118
L6 15.1 15.8 0.594 0.622
L7 6 6.6 0.236
L9 4.44 0.175

Dia 3.65 3.85 0.144 0.152

mm inch

0.205

0.173

0.622

0.201

0.260

OUTLINE AND

MECHANICAL DATA

Heptawatt H

15/16

L4962

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