Datasheet MAX6369, MAX6370, MAX6371, MAX6372, MAX6373, MAX6374 (Maxim) - 6

Pin-Selectable Watchdog Timers
VCC WDI MAX6369–MAX6374 TRANSITION EN DETECTOR SET 2 CONTROL CLEAR SET 1 LOGIC ENABLE SET 0 SET WATCHDOG TIMEOUT OUT OUTPUT WDO SET STARTUP DELAY WATCHDOG TIMER CIRCUITRY GND
MAX6369–MAX6374
Figure 1. Functional Diagram V t CC SETUP tDELAY tWD t t WD WD WDI A A B C D E F G E WDO tWDO A TRANSITIONS ON WDI IGNORED DURING SETUP DELAY. B TRANSITION(S) ON WDI IGNORED DURING STARTUP DELAY PERIOD. C WATCHDOG TIMER STARTS AFTER STARTUP DELAY AND WDO IS DEASSERTED. D TRANSITION OCCURS BEFORE WATCHDOG TIMEOUT PERIOD. WATCHDOG TIMER CLEARS AND STARTS TIMER AGAIN. E WATCHDOG TIMES OUT, WDO ASSERTS. F TRANSITIONS ON WDI IGNORED WHEN WDO ASSERTED. G WATCHDOG TIMER STARTS AFTER WDO DEASSERTS. Figure 2. Watchdog Timing • Watchdog Timeout Period: • Watchdog Output/Timing Options: Normal operating watchdog timeout period after the Open drain, active low with 100ms minimum watch- initial startup delay. dog output pulse (MAX6369/MAX6371/MAX6373). A watchdog output pulse is asserted if a valid watch- Push-pull, active low with 1ms minimum watchdog dog input transition is not received before the timeout output pulse (MAX6370/MAX6372/MAX6374). period elapses. Each device has a watchdog startup delay that is initi- Eight pin-selectable timeout period options for each ated when the supervisor is first powered or after the device, from 30µs to 60s. user modifies any of the logic control set inputs. The Pin-selectable watchdog timer disable feature. watchdog timer will not begin to count down until the
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