General Description
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:
1) µP reset: Assertion of RESET and RESET outputs during power-up, power-down,
   and brownout conditions. RESET is guaranteed valid for VCC down to 1V.
2) Manual-reset input.
3) 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.
4) Watchdog fault output: Assertion of WDO if the watch
   dog input is not toggled within a preset timeout
   period.
5) Pulsed watchdog output: Advance warning of
   impending WDO assertion from watchdog timeout
   that causes hardware shutdown.
6) 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%).

FEATUREs
♦ 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)

APPLICATIONs
   Computers
   Controllers
   Intelligent Instruments
   Critical µP Power Monitoring