µP Supervisory Circuits with Windowed (Min/Max) Watchdog and Manual Reset

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).

Applications

* Automotive * Embedded Control Systems * Industrial * Medical

* Min/Max (Windowed) Watchdog, 8 Factory-Trimmed Timing Options

* Pulsed Open-Drain, Active-Low Watchdog Output

* Power-On Reset

* Precision Monitoring of +2.5V, +3.0V, +3.3V, and +5.0V Power Supplies

* Open-Drain or Push-Pull Active-Low RESET Outputs

* Low-Power Operation (23µA typ)

* Debounced Manual Reset Input

* Guaranteed Reset Valid to VCC = +1.2V

* AEC-Q100 Qualified MAX6324HUT44/V+T