Rev 1.1a 3.19.2005

Microsemi Inc.

Copyright

© 1994

11861 Western Avenue

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∞

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∞ Garden Grove, CA 92841

1

(714) 898-8121

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∞ FAX: (714) 893-2570

SG1526B/SG2526B/SG3526B

DESCRIPTION

The SG1526B is a high-performance pulse width modulator for switching

power supplies which offers improved functional and electrical characteris-

tics over the industry-standard SG1526. A direct pin-for-pin replacement for

the earlier device with all its features, it incorporates the following enhance-

ments: a bandgap reference circuit for improved regulation and drift

characteristics, improved undervoltage lockout, lower temperature coeffi-

cients on oscillator frequency and current-sense threshold, tighter toler-

ance on softstart time, much faster SHUTDOWN response, improved

double-pulse supperession logic for higher speed operation, and an im-

proved output driver design with low shoot-through current, and faster rise

and fall times. This versatile device can be used to implement single-ended

or push-pull switching regulators of either polarity, both transformer-less

and transformer-coupled. The SG1526B is specified for operation over the

full military ambient temperature range of -55

°C to 150°C. The SG2526B

is characterized for the industrial range of -25

°C to 150°C, and the SG3526B

is designed for the commercial range of 0

°C to 125°C.

REGULATING PULSE WIDTH MODULATOR

BLOCK DIAGRAM

+V

IN

METERING

F/F

TOGGLE

F/F

MEMORY

F/F

R

D

R

T

C

T

GROUND

Oscillator

Reference

Regulator

Undervoltage

Lockout

Soft

Start

RESET

C

SOFTSTART

COMPENSATION

+ ERROR

— ERROR

+ C.S.

— C.S.

SHUTDOWN

Q

Q

Q

Q

OUTPUT B

+V

C

OUTPUT A

+V

IN

FEATURES

••••• 8 to 35 volt operation

••••• 5V low drift 1% bandgap reference

••••• 1Hz to 500KHz oscillator range

••••• Dual 100mA source/sink

••••• Digital current limiting

••••• Double pulse suppression

••••• Programmable deadtime

••••• Improved undervoltage lockout

••••• Single pulse metering

••••• Programmable soft-start

••••• Wide current limit common mode range

••••• TTL/CMOS compatible logic ports

••••• Symmetry correction capability

••••• Guaranteed 6 unit synchronization

••••• Shoot thru currents less than 100mA

••••• Improved shutdown delay

••••• Improved rise and fall time

HIGH RELIABILITY FEATURES - SG1526B

♦

♦

♦

♦

♦ Available to MIL-STD-883

♦

♦

♦

♦

♦ MIL-M38510/12603BVA - JAN1526BJ

♦

♦

♦

♦

♦ Radiation data available

♦

♦

♦

♦

♦ LMI level "S" processing available

Amp

V

REF

To Internal

Circuitry

SYNC

S

R

D

S

T

Q