WD_EN

RST

A

B

A B

C WATCHDOG DOES NOT START AFTER START-UP PERIOD SINCE WD_EN IS HELD LOW.

D TRANSITION ON WDI IGNORED WHEN WD_EN IS HELD LOW.

E WATCHDOG TIMER STARTS AFTER RISING EDGE ON WD_EN.

F WATCHDOG TIMES OUT, WDO ASSERTS AND THE NEXT WATCHDOG TIMER STARTS AT THE FALLING EDGE OF WDO.

G TRANSITION ON WDI IGNORED AFTER WDO ASSERTS.

C

D E

F

WDO

WDI

G

H

H WATCHDOG TIMES OUT, WDO ASSERTS.

Figure 3. Watchdog Timing Characteristics with WD_EN Active After Startup Time

Watchdog Input Signal

Watchdog timing is measured from the last WDI falling edge associated with a pulse of at least 1µs (min) in width.

WDI transitions are ignored when WDO and/or RST are asserted, and during the startup delay period. Watchdog input

MAX16152/MAX16153/

MAX16154/MAX16155

nanoPower Supervisor and Watchdog Timer

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