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 laser-trimmed reset thresholds are available with ±2.5% accuracy from +2.32V to +4.63V. Valid active-low RESET output is guaranteed down to VCC = +1.2V.

The active-low RESET output is either push-pull (MAX6323) or open-drain (MAX6324). active-low RESET is asserted low when VCC falls below the reset threshold, or when the manual reset input (active-low MR) is asserted low. active-low RESET remains asserted for at least 100ms after VCC rises above the reset threshold and active-low MR is deasserted.

The watchdog pulse output (active-low WDPO) utilizes an open-drain 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. Active-low 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).