Microprocessor Supervisory Circuits

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5

______________________________________________________________Pin Description

NAME

FUNCTION

MAX805L

1

1

2

2

+5V Supply Input

3

3

GND

Ground

4

4

PFI

5

5

PFO

6

6

WDI

7

RESET

8

8

Power-Fail Comparator Input. When PFI is less than 1.25V, PFO goes

Power-Fail Output. When PFI is less than 1.25V, PFO goes low;

otherwise PFO stays high.

Watchdog Input. If WDI remains high or low for 1.6sec, the internal

watchdog timer runs out and reset is triggered. If WDI is left floating or

connected to a high-impedance three-state buffer, the watchdog

feature is disabled. The internal watchdog timer clears whenever reset

is asserted, WDI is three-stated, or WDI sees a rising or falling edge.

PIN

MAX690A/MAX692A

MAX802L/MAX802M

Reset Output. Whenever RESET is triggered, it pulses low for 200ms. It

MAX690A/MAX802L and 4.4V in the MAX692A/MAX802M) and remains

timeout also triggers RESET.

–

7

RESET

Active-High Reset Output is the inverse of RESET. When RESET is

higher.