SG1526B Datasheet, PDF (1/9 Pages) Microsemi Corporation – REGULATING PULSE WIDTH MODULATOR

SG1526B/SG2526B/SG3526B
REGULATING PULSE WIDTH MODULATOR
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.
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
BLOCK DIAGRAM
V_REF
+V_IN
GROUND
R_D
R_T
C_T
Reference
Regulator
Undervoltage
Lockout
Oscillator
To Internal
Circuitry
SYNC
+V_C
OUTPUT A
RESET
C_SOFTSTART
COMPENSATION
+ ERROR
— ERROR
+ C.S.
— C.S.
Soft
Start
+V_IN
Amp
S
Q
D
Q
S
RQ
MEMORY
F/F
Q
T
Q
TOGGLE
F/F
METERING
F/F
OUTPUT B
SHUTDOWN
4/90 Rev 1.1 2/94
Copyright © 1994
LINFINITY Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
1
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