Pin-selectable watchdog timer with open-drain output

The MAX6369–MAX6374 are pin-selectable watchdog timers that supervise microprocessor (µP) activity and signal when a system is operating improperly. During normal operation, the microprocessor should repeatedly toggle the watchdog input (WDI) before the selected watchdog timeout period elapses to demonstrate that the system is processing code properly. If the µP does not provide a valid watchdog input transition before the timeout period expires, the supervisor asserts a watchdog (active-low WDO) output to signal that the system is not executing the desired instructions within the expected time frame. The watchdog output pulse can be used to reset the µP or interrupt the system to warn of processing errors.

The MAX6369–MAX6374 are flexible watchdog timer supervisors that can increase system reliability through notification of code execution errors. The family offers several pin-selectable watchdog timing options to match a wide range of system timing applications:

• Watchdog startup delay: provides an initial delay before the watchdog timer is started.
• Watchdog timeout period: normal operating watchdog timeout period after the initial startup delay.
• Watchdog output/timing options: open drain (100ms) or push-pull (1ms).

The MAX6369-MAX6374 operate over a +2.5V to +5.5V supply range and are available in miniature 8-pin SOT23 packages.