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SLUS233A – OCTOBER 1999 – REVISED SEPTEMBER 2008
Quad Supply and Line Monitor
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FEATURES
Inputs for Monitoring up to Four Separate
Supply Voltage Levels
Internal Inverter for Sensing a Negative Supply
Voltage
Line/Switch Sense Input for Early Power
Source Failure Warning
Programmable Under- and Over-Voltage Fault
Thresholds with Proportional Hysteresis
A Precision 2.5-V Reference
General Purpose Op-Amp for Auxiliary Use
Three High Current, >3 0mA, Open-Collector
Outputs Indicate Over-Voltage, Under-Voltage
and Power OK Conditions
8-V to 40-V Supply Operation with 7-mA
Stand-By Current
DESCRIPTION
The UC1903 family of quad supply and line monitor
integrated circuits will respond to under- and
over-voltage conditions on up to four continuously
monitored voltage levels. An internal op-amp inverter
allows at least one of these levels to be negative. A
separate line/switcher sense input is available to
provide early warning of line or other power source
failures.
The fault window adjustment circuit on these devices
provides easy programming of under- and
over-voltage thresholds. The thresholds, centered
around a precision 2.5-V reference, have an input
hysteresis that scales with the window width for
precise, glitch-free operation. A reference output pin
allows the sense input fault windows to be scaled
independently using simple resistive dividers.
The three open collector outputs on these devices
sink in excess of 30 mA of load current when active.
The under- and over-voltage outputs respond after
separate, user defined, delays to respective fault
conditions. The third output is active during any fault
condition including under- and over-voltage,
line/switcher faults, and input supply under-voltage.
The off state of this output indicates a "power OK"
situation.
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BLOCK DIAGRAM
Note: Pin numbers refer to J, N and DW packages.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
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