Datasheet SG3525AN, SG3525AP Datasheet (SGS Thomson Microelectronics)

SG2525A



REGULATINGPULSE WIDTHMODULATORS

.

8 TO35 V OPERATION

.5.1V REFERENCETRIMMED TO

.

100Hz TO 500KHzOSCILLATORRANGE

±

1%

.SEPARATEOSCILLATORSYNCTERMINAL

.

ADJUSTABLEDEADTIMECONTROL

.INTERNALSOFT-START

.PULSE-BY-PULSESHUTDOWN

.INPUT UNDERVOLTAGE LOCKOUT WITH

HYSTERESIS

.

LATCHING PWM TO PREVENT MULTIPLE
PULSES

.

DUALSOURCE/SINKOUTPUT DRIVERS

DES CRIPTION

The SG3525Aseriesof pulse widthmodulatorinte­grated circuitsare designed to offerimprovedper­formance and lowered external parts count when
used indesigningalltypesof switchingpower sup­plies.Theon-chip+5.1 V referenceistrimmedto±
1 % andthe inputcommon-moderangeoftheerror
amplifierincludesthereferencevoltageeliminating
externalresistors. A sync inputto the oscillatoral­lowsmultipleunitstobeslavedor a singleunittobe
synchronizedto an externalsystemclock. A single
resistorbetweentheC
provide a wide range of dead time ad- justment.
Thesedevicesalsofeaturebuilt-insoft-startcircuitry
with only an external timing capacitor required. A
shutdownterminalcontrolsboththesoft-startcircu­ity and the output stages, providing instantaneous

andthedischargeterminals

T

SG3525A

DIP16 16( Na rr ow)

turn off through the PWM latch with pulsed shut­down,as wellassoft-startrecyclewithlongershut­downcommands.Thesefunctionsarealsocontrol­ledbyanundervoltagelockoutwhichkeepstheout­puts off and the soft-startcapacitordischarged for
sub-normalinputvoltages.Thislockoutcircuitryin­cludesapproximately500 mVof hysteresisforjitter­free operation. Another featureof these PWM cir­cuits is a latch following the comparator. Once a
PWM pulses has been terminated for any reason,
theoutputswill remainoff for thedurationofthepe­riod. The latch is reset with each clock pulse. The
output stages are totem-pole designs capable of
sourcing or sinking in excess of 200 mA. The
SG3525AoutputstagefeaturesNORlogic,givinga
LOWoutputfor anOFFstate.

PI N CO NNECTI O N S AND ORDE RING NUMBERS (top view)

Type Plastic DIP SO16

SG2525A SG2525AN SG2525AP
SG3525A SG3525AN SG3525AP

June 2000

1/12

SG2525A-SG3525A

ABSOLUTEMAXIMUMRATINGS

Symbol Parameter Value Unit

V

V

I

OSC

I

o

I

R

I

T

P

tot

T

T

stg

T

op

THERMAL DATA

Symbol Parameter SO16 DIP16 Unit

R

th j-pins

R

th j-amb

R

th j-alumina

*

Thermalresistancejunction-aluminawiththe devicesolderedon themiddleofanaluminasupportingsubstratemeasuring15× 20mm; 0.65mm
thickness withinfiniteheatsink.

Supply Voltage 40 V

i

Collector Supply Voltage 40 V

C

Oscillator Charging Current 5 mA
Output Current, Source or Sink 500 mA
Reference Output Current 50 mA
Current through CTTerminal

Logic Inputs
Analog Inputs

Total Power Dissipation at T
Junction Temperature Range – 55 to 150

j

=70°C 1000 mW

amb

5

– 0.3 to + 5.5

– 0.3 to V

Storage Temperature Range – 65 to 150
Operating Ambient Temperature : SG2525A

SG3525A

–25to85

0to70

Thermal Resistance Junction-pins Max
Thermal Resistance Junction-ambient Max
Thermal Resistance Junction-alumina (*) Max 50

i

50
80

°C/W
°
°C/W

mA

V
V

C

°

C

°

C

°
°C

C/W

BLOCK DI AGRAM

2/12

ELECTRICALCHARACTERISTICS

(V# i = 20 V, andoveroperatingtemperature, unlessotherwisespecified)

SG2525A-SG3525A

Symbol Parameter Test Conditions

SG2525A SG3525A

Unit

Min. Typ. Max. Min. Typ. Max.

REFERENCE SECTION

V

V

∆
∆V

V

∆

REF

Output Voltage Tj=25°C 5.05 5.1 5.15 5 5.1 5.2 V

REF

Line Regulation Vi= 8 to 35 V 10 20 10 20 mV

REF

Load Regulation IL= 0 to 20 mA 20 50 20 50 mV

REF

/∆T* Temp. Stability Over Operating Range 20 50 20 50 mV

* Total Output Variation Line, Load and

5 5.2 4.95 5.25 V

Temperature

Short Circuit Current V

* Output Noise Voltage 10 Hz≤f≤10 kHz,

∆V

* Long Term Stability Tj= 125 °C, 1000 hrs 20 50 20 50 mV

REF

=0Tj=25°C 80 100 80 100 mA

REF

40 200 40 200µVrms

=25°C

T

j

OSCILLATOR SECTION * *

*, • Initial Accuracy T
*,

Voltage Stability V

•

=25°C ±2 ±6 ±2 ±6%

j

= 8 to 35 V

i

0.3

±

1

±

1

±

2%

±

∆f/∆T* Temperature Stability Over Operating Range ± 3 ± 6 ± 3 ± 6%

f

MIN

f

MAX

Minimum Frequency RT= 200 KΩ CT= 0.1µF 120 120 Hz
Maximum Frequency RT=2KΩCT= 470 pF 400 400 KHz
Current Mirror I

= 2 mA 1.7 2 2.2 1.7 2 2.2 mA

RT

*, • Clock Amplitude 3 3.5 3 3.5 V
*,

Clock Width T

•

=25°C 0.3 0.5 1 0.3 0.5 1

j

s

µ

Sync Threshold 1.2 2 2.8 1.2 2 2.8 V
Sync Input Current Sync Voltage = 3.5 V 1 2.5 1 2.5 mA

ERROR AMPLIFIER SECTION (V

V

I

Input Offset Voltage 0.5 5 2 10 mV

OS

Input Bias Current 1 10 1 10

I

b

Input Offset Current 1 1 µA

os

DC Open Loop Gain R

* Gain Bandwidth

= 5.1 V)

CM

≥ 10 MΩ 60 75 60 75 dB

L

= 0 dB Tj=25°C1 2 1 2 MHz

G

v

A

µ

Product

*, ❚ DC Transconduct. 30 KΩ ≤ R

=25°C

T

j

≤ 1MΩ

L

1.1 1.5 1.1 1.5 ms

Output Low Level 0.2 0.5 0.2 0.5 V
Output High Level 3.8 5.6 3.8 5.6 V

CMR Comm. Mode Reject. V

PSR Supply Voltage

= 1.5 to 5.2 V 60 75 60 75 dB

CM

= 8 to 35 V 50 60 50 60 dB

V

i

Rejection

3/12

SG2525A-SG3525A

ELECTRICAL CHARACTERISTICS

Symbol Parameter Test Conditions

(continued)

SG2525A SG3525A

Min. Typ. Max. Min. Typ. Max.

PWM COMPARATOR

Minimum Duty-cycle 0 0 %

• Maximum Duty-cycle 45 49 45 49 %
Input Threshold Zero Duty-cycle 0.7 0.9 0.7 0.9 V

•

Maximum Duty-cycle 3.3 3.6 3.3 3.6 V

* Input Bias Current 0.05 1 0.05 1 µA

SHUTDOWN SECTION

Soft Start Current V
Soft Start Low Level V
Shutdown Threshold To outputs, V

Shutdown Input Current V

* Shutdown Delay V

OUTPUT DRIVERS (each output) (V

Output Low Level I

Output High Level I

Under-Voltage Lockout V
Collector Leakage VC= 35 V 200 200

I

C

t

* Rise Time CL= 1 nF, Tj=25°C 100 600 100 600 ns

r

* Fall Time CL= 1 nF, Tj=25°C 50 300 50 300 ns

t

f

= 0 V, VSS=0V 255080255080 µA

SD

= 2.5 V 0.4 0.7 0.4 0.7 V

SD

= 5.1 V

=25°C

T

j

= 2.5 V 0.4 1 0.4 1 mA

SD

= 2.5 V Tj=25°C 0.2 0.5 0.2 0.5 µs

SD

=20V)

C

= 20 mA 0.2 0.4 0.2 0.4 V

sink

I

= 100 mA 1 2 1 2 V

sink

=20mA 1819 1819 V

source

= 100 mA 17 18 17 18 V

I

source

and Vss= High 6 7 8 6 7 8 V

comp

SS

0.6 0.8 1 0.6 0.8 1 V

TOTAL STANDBY CURRENT

Supply Current Vi= 35 V 14 20 14 20 mA

I

s

Unit

µ

A

*

These parameters, althoughguaranteed over therecommended operating conditions, are not 100% tested inproduction.

•

Testedat f
f=

DC transconductance (gM) relatesto DCopen-loopvoltagegain (Gv) according tothefollowingequation: Gv=gMRLwhereRListhe resistance

.

frompin 9 to ground. Theminimumg

=40 KHz (RT= 3.6 KΩ,CT=10nF, RD=0Ω). Approximateoscillatorfrequency is defined by:

osc

1

C

(0.7 RT+3RD)

T

specification is used to calculateminimum Gvwhenthe error amplifieroutput is loaded.

M

4/12

TEST CI RCUIT

SG2525A-SG3525A

5/12

SG2525A-SG3525A

RECOMMENDED OPERATINGCONDITIONS (•)

Parameter Value

Input Voltage (V
Collector Supply Voltage (V
Sink/Source Load Current (steady state) 0 to 100 mA
Sink/Source Load Current (peak) 0 to 400 mA
Reference Load Current 0to20mA
Oscillator Frequency Range 100 Hz to 400 KHz
Oscillator Timing Resistor 2 KΩ to 150 KΩ
Oscillator Timing Capacitor 0.001µF to 0.1µF
Dead Time Resistor Range 0 to 500

• (

Range over whichthe device is functionaland parameterlimits areguaranteed.

⋅)

) 8to35V

i

) 4.5 to 35 V

C

Ω

Figure 1 :

Oscillator Charge Time vs. R

and C

.

T

Figure 3 :OutputSaturation

Characteristics.

T

Figure 2 :

Oscilla tor Discharge Time vs. R

and C

.

T

D

Figure4 : Error AmplifierVoltageGain and

Phasevs. Frequency.

6/12

SG2525A-SG3525A

Figure5

: ErrorAmplifier.

PRINCIPLES OF OPERATION

SHUTDOWN OPTIONS(see Block Diagram)
Since both the compensation and soft-starttermi-

nals (Pins 9 and 8) have current source pull-ups,
either canreadily accept a pull-down signal which
onlyhastosinka maximumof100

µA

toturnoffthe
outputs.Thisissubjecttotheadded requirementof
dischargingwhateverexternalcapacitancemay be
attachedto thesepins.

Analternateapproachistheuseoftheshutdowncir­cuitry of Pin 10 which has been improved to en­hance the available shutdown options. Activating
this circuit by applying a positive signal on Pin 10
performstwo functions: the PWM latch isimmedi-

ately set providing the fastestturn-offsignal to the
outputs ; and a 150 µA current sinkbegins to dis­chargethe externalsoft-startcapacitor.If the shut­down command is short, the PWM signal is termi­nated without significantdischarge of thesoft-start
capacitor,thus,allowing,forexample,a convenient
implementation of pulse-by-pulse current limiting.
HoldingPin 10highfora longerduration,however,
will ultimatelydischarge this external capacitor,re­cyclingslow turn-on uponrelease.

Pin 10 should not be left floating as noise pickup
couldconceivablyinterruptnormaloperation.

7/12

SG2525A-SG3525A

Figure 6

: OscillatorSchematic.

Figure7:

Output Circuit (1/2 circuit shown).

8/12

SG2525A-SG3525A

Figure 8. Figure 9

For single-ended supplies, the driver outputs are
grounded.The V

terminalisswitched to groundby

C

thetotem-polesourcetransistorsonalternateoscil­latorcycles.

In conventionalpush-pull bipolar designs, forward
base drive is controlled by R1-R3. Rapid turn-off
times for the power devices are achieved with
speed-upcapacitorsC

.

andC2.

1

Figure 1 0. Figure 1 1.

Thelowsourceimpedanceoftheoutputdriverspro­vides rapid charging of Power Mos input capaci­tancewhile minimizing externalcomponents.

Low power transformers can be driven directly.
Automaticresetoccursduringdeadtime,whenboth
endsof theprimarywindingareswitchedtoground.

9/12

SG2525A-SG3525A

DIM.

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

a1 0.51 0.020

B 0.77 1.65 0.030 0.065

b 0.5 0.020

b1 0.25 0.010

D 20 0.787

E 8.5 0.335

e 2.54 0.100

e3 17.78 0.700

F 7.1 0.280

I 5.1 0.201
L 3.3 0.130

Z 1.27 0.050

mm inch

OUTLINE AND

MECHANICAL DATA

DIP16

10/12

SG2525A-SG3525A

DIM.

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

A 1.75 0.069

a1 0.1 0.25 0.004
a2 1.6 0.063

b 0.35 0.46 0.014 0.018

b1 0.19 0.25 0.007 0.010

C 0.5 0.020

c1 45°(typ.)

D (1) 9.8 10 0.386 0.394

E 5.8 6.2 0.228 0.244
e 1.27 0.050

e3 8.89 0.350

F (1) 3.8 4 0.150 0.157

G 4.6 5.3 0.181 0.209
L 0.4 1.27 0.016 0.050

M 0.62 0.024

S

mm inch

0.009

8°(max.)

OUTLINE AND

MECHANICAL DATA

SO16 Narrow

(1) D andF do not includemold flashor protrusions. Moldflash or potrusions shall not exceed 0.15mm (.006inch).

11/12

SG2525A-SG3525A

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