The UC1903 family of quad supply and line monitor integrated circuits will respondto 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.
●An additional, uncommitted, general purpose op-amp is also included. This op-amp, capable of sourcing 20 mA of output current, can be used for a number of auxiliary functions including the sensing and amplification of a feedback error signal when the 2.5-V output is used as a system reference.
●These parts operate over an 8-V to 40-V input supply range and require a typical stand-by current of only 7 mA.
● Inputs for Monitoring up to FourSeparate 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
