Rev 1.2a 3.19.2005

Microsemi, Inc. - Integrated Products

Copyright

© 1997

11861 Western Avenue

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(714) 898-8121

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SG1548/SG2548/SG3548

QUAD POWER FAULT MONITOR

DESCRIPTION

The SG1548 is an integrated circuit capable of monitoring up to four

positive DC supply voltages simultaneously for overvoltage and

undervoltage fault conditions.

An on-chip inverting op amp also

allows monitoring one negative DC voltage.

The fault tolerance

window is accurately programmable from ±5% to ±40% using a simple

divider network on the 2.5V reference. A single external capacitor sets

the fault indication delay, eliminating false outputs due to switching

noise, logic transition current spikes, and short-term AC line interrup-

tions. An additional comparator referenced to 2.5V allows the AC line

to be monitored for undervoltage conditions or for generation of a line

clock.

The comparator can also be used for programmable

undervoltage lockout in a switching power supply.

Uncommitted

collector and emitter outputs permit both inverting and non-inverting

operation. External availability of the precision 2.5V reference and

open-collector logic outputs permit expansion to monitor additional

voltage using available open-collector quad comparators.

FEATURES

••••• Monitors four DC voltages and the AC line

••••• Precision 2.5V ±1% low-drift reference

••••• Fault tolerance adjustable from ±5% to ±40%

••••• ±3% trip threshold tolerance over temperature

••••• Separate 10mA, 40V overvoltage, undervoltage

and AC line fault outputs

••••• Fault delay programmable with a single capacitor

••••• 30mV comparator hysteresis to prevent oscilla-

tions

••••• On-chip inverting op amp for negative voltage

••••• Open-collector output logic or expandability

••••• Operation from 4.5V to 40V supply

HIGH RELIABILITY FEATURES - SG1548

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♦ Available to MIL-STD-883

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♦ Radiation data available

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♦ LMI level "S" processing available

BLOCK DIAGRAM