5-Pin µP Supervisory Circuits with

Watchdog and Manual Reset

6

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_______________Detailed Description

A microprocessor’s (µP) reset input starts or restarts the

µP in a known state. The reset output of the MAX6316–

MAX6322 µP supervisory circuits interfaces with the

reset input of the µP, preventing code-execution errors

during power-up, power-down, and brownout condi-

tions (see the

Typical Operating Circuit). The MAX6316/

MAX6317/MAX6318/MAX6320/MAX6321 are also capa-

ble of asserting a reset should the µP become stuck in

an infinite loop.

Reset Output

The MAX6316L/MAX6318LH/MAX6319LH feature an

active-low reset output, while the MAX6317H/

MAX6318_H/MAX6319_H/MAX6321HP/MAX6322HP

feature an active-high reset output. RESET is guaran-

teed to be a logic low and RESET is guaranteed to be a

(MAX6316_/MAX6317H/MAX6319_H/MAX6320P/

MAX6322HP only), or if the WDI pin is not serviced within

low to high, or after the watchdog timer asserts the reset

(MAX6316_/MAX6317H/MAX6318_H/MAX6320P/

expires, the reset output deasserts, and the watchdog

timer restarts from zero (Figure 2).

MAX6316–MAX6322

WDI

(ALL EXCEPT

MAX6319/MAX6322)

1.23V

52k

52k

GND

RESET

(ALL EXCEPT

MAX6316/MAX6320P)

RESET

(ALL EXCEPT MAX6317)

MR

(ALL EXCEPT

MAX6318/MAX6321)

RESET

GENERATOR

WATCHDOG

TIMER

WATCHDOG

TRANSITION

DETECTOR

Figure 1. Functional Diagram

1V

1V

RESET

GND

RESET

GND

Figure 2. Reset Timing Diagram