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
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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
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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
+V
C
To Internal
Circuitry
Oscillator
SYNC
OUTPUT A
RESET
C
SOFTSTART
COMPENSATION
+ ERROR
Soft
Start
+V
IN
S
Amp
D
Q
METERING
F/F
Q
S
T
R
Q
Q
Q
TOGGLE
F/F
OUTPUT B
MEMORY
F/F
— ERROR
+ C.S.
— C.S.
SHUTDOWN
4/90 Rev 1.1 2/94
Copyright
©
1994
1
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∞
Garden Grove, CA 92841
(714) 898-8121
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FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
MICROSEMI [ MICROSEMI CORPORATION ]
