UC1903 Datasheet | Texas Instruments

UC1903 UC2903 UC3903 .ti. ........................................................................................................................................ SLUS233A - OCTOBER 1999 - REVISED SEPTEMBER 2008 Quad Supply and Line Monitor 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 0m A, Open-Collector Outputs Indicate Over-Voltage, Under-Voltage and Power OK Conditions - 8-V to 40-V Supply Operation with 7-m A 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 m A 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. BLOCK DIAGRAM Note:...