MAX6323

19-1838; Rev 2; 2/03 µP Supervisory Circuits with Windowed (Min/Max) Watchdog and Manual Reset General Description The MAX6323/MAX6324 microprocessor (µP) supervisory circuits monitor power supplies and µP activity in digital systems. A watchdog timer looks for activity outside an expected window of operation. Six lasertrimmed reset thresholds are available with ±2.5% accuracy from +2.32V to +4.63V. Valid RESET output is guaranteed down to VCC = +1.2V. The RESET output is either push-pull (MAX6323) or open-drain (MAX6324). RESET is asserted low when VCC falls below the reset threshold, or when the manual reset input (MR) is asserted low. RESET remains asserted for at least 100ms after VCC rises above the reset threshold and MR is deasserted. The watchdog pulse output (WDPO) utilizes an opendrain configuration. It can be triggered either by a fast timeout fault (watchdog input pulses are too close to each other) or a slow timeout fault (no watchdog input pulse is observed within the timeout period). The watchdog timeout is measured from the last falling edge of watchdog input (WDI) with a minimum pulse width of 300ns. WDPO is asserted for 1ms when a fault is observed. Eight laser-trimmed timeout periods are available. The MAX6323/MAX6324 are offered in a 6-pin SOT23 package and operate over the extended temperature range (-40°C to +125°C). o Min/Max (Windowed) Watchdog, 8 Factory-Trimmed Timing Options o Pulsed Open-Drain, Active-Low Watchdog Output o Power-On Reset o Precisi...