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