Nanopower µP Supervisory Circuits with

Manual Reset and Watchdog Timer

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9

MAX6867/MAX6868/MAX6869 Pin Description

PIN

MAX6867/

MAX6869

MAX6868

NAME

FUNCTION

11

WDI

Watchdog Input. If WDI remains high or low for longer than the watchdog timeout

period, the internal watchdog timer expires, and a reset is triggered for the reset

timeout period. The internal watchdog timer clears whenever reset is asserted,

the manual reset is asserted, or WDI sees a rising or falling edge.

22

GND

Ground

33

MR

Active-Low Manual Reset Input. Drive MR low to initiate a reset. The reset output

remains asserted while MR is held low and for the reset timeout period after MR

4—

RESET

Active-Low Open-Drain or Push-Pull Reset Output. RESET transitions from high to

watchdog timer expires. RESET remains low for the reset timeout period after

RESET outputs require an external pullup resistor.

55

a 0.1µF capacitor to GND.

—4

RESET

Active-High Push-Pull Reset Output. RESET transitions from low to high when

exceeds the device reset threshold, MR deasserts, or after the watchdog timer