The MAX792/MAX820 microprocessor (µP) supervisory circuits provide the most functions for power-supply and watchdog monitoring in systems without battery backup. Built-in features include the following: * µP reset: Assertion of RESET and active-low RESET outputs during power-up, power-down, and brownout conditions. Active-low RESET is guaranteed valid for VCC down to 1V. * Manual-reset input. * Two-stage power-fail warning: A separate low-line comparator compares VCC to a preset threshold 120mV above the reset threshold; the low-line and reset thresholds can be programmed externally. * Watchdog fault output: Assertion of active-low WDO if the watchdog input is not toggled within a preset timeout period. * Pulsed watchdog output: Advance warning of impending active-low WDO assertion from watchdog timeout that causes hardware shutdown. * Write protection of CMOS RAM, EEPROM, or other memory devices. The MAX792 and MAX820 are identical, except the MAX820 guarantees higher low-line and reset threshold accuracy (±2%).Applications * Computers: Desktop, Workstation, Server * Controllers * Critical µP Monitoring * Intelligent Instruments * Manual-Reset Input * 200ms Power OK/Reset Time Delay * Independent Watchdog Timer-Preset or Adjustable * On-Board Gating of Chip-Enable Signals * Memory Write-Cycle Completion * 10ns (max) Chip-Enable Gate Propagation Delay * Voltage Monitor for Overvoltage Warning * ±2% Reset and Low-Line Threshold Accuracy (MAX820, external programming mode)