December 2014 Rev. 1.3a www.microsemi.com 1
© 2014 Microsemi Corporation
QUAD POWER FAULT MONITOR
Block Diagram
Figure 1 · Block Diagram
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 Oscillations
On-Chip Inverting Op-Amp for Negative Voltage
Open-Collector Output Logic or Expandability
Operation from 4.5V to 40V Supply
High Reliability Features
Following are the high reliability features of SG1548:
Available to MIL-STD-883, ¶ 1.2.1
Radiation data available
MSC-AMS level "S" processing available
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 interruptions.
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
.
SG1548
