General Description
The MAX6821–MAX6825 are low-voltage microprocessor (µP) supervisory circuits that combine voltage monitoring, watchdog timer, and manual reset input functions in a 5-pin SOT23 package. Microprocessor supervisory circuits significantly improve system reliability and accuracy compared to separate ICs or discrete components. These devices assert a reset signal whenever the monitored voltage drops below its preset threshold, keeping it asserted for a minimum timeout period after VCC rises above the threshold. In addition, a watchdog timer monitors against code execution errors. A debounced manual reset is also available. The MAX6821–MAX6825 monitor voltages from +1.8V to +5.0V. These outputs are guaranteed to be in the correct state for VCC down to +1.0V.

Features
♦ Monitors +1.8V, +2.5V, +3.0V, +3.3V, +5.0V
   Supplies
♦ 140ms (min) Reset Timeout Delay
♦ 1.6s Watchdog Timeout Period
   (MAX6821/MAX6822/MAX6823/MAX6824)
♦ Manual Reset Input
   (MAX6821/MAX6822/MAX6823/MAX6825)
♦ Three Reset Output Options
   Push-Pull RESET
   Push-Pull RESET
   Open-Drain RESET
♦ Guaranteed Reset Valid to VCC = +1.0V
♦ Immune to Short Negative VCC Transients
♦ No External Components
♦ Small 5-Pin SOT23 Packages

Applications
   Set-Top Boxes
   Computers and Controllers
   Embedded Controllers
   Intelligent Instruments
   Automotive Systems
   Critical µP Monitoring
   Portable/Battery Powered Equipment