LTC1921

Final Electrical Specifications LTC1921 Dual –48V Supply and Fuse Monitor FEATURES s May 2002 DESCRIPTIO s s s s s s s s s Independently Monitors Two –48V Supplies for – Undervoltage Faults: –38.5V ±1VMAX – Overvoltage Faults: –70V ±1.5VMAX Accurately Detects Undervoltage Fault Recovery: –43V ±0.5VMAX Monitors Two External Fuses Operates from –10V to –80V Tolerates DC Faults to –100V Tolerates Accidental Supply Reversal to 100V Withstands Transient Voltages Up to 200V/–200V Small Footprint: 8-Lead MSOP Package Requires No Precision External Components Specified from – 40°C to 85°C The LTC®1921 monitors two independent – 48V supplies, including their fuses, and drives up to three optoisolators to indicate status, in accordance with standard backplane specifications. Requiring only three noncritical resistors and optoisolators, the LTC1921 replaces multiple voltage comparators, a voltage reference and several precision resistors. The monitor features dual supply overvoltage and undervoltage detection circuits. The preset trip thresholds include overvoltage, undervoltage and undervoltage recovery that are guaranteed over temperature and meet or exceed common backplane specifications. Additional built-in circuitry detects the condition of supply fuses. Overvoltage and undervoltage detectors ignore fast supply transients, eliminating false detection. The LTC1921 operates from –10V to –80V with a typical power dissipation of less than 10mW. The LTC1921 is available in an 8-...