REV. 0

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a

Microprocessor

Supervisory Circuits

ADM698/ADM699

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700

Fax: 617/326-8703

FUNCTIONAL BLOCK DIAGRAM

RESET

GENERATOR

4.65V

WATCHDOG

INPUT

WDI

*

ADM698/

ADM699

RESET

WATCHDOG

OUTPUT WDO

*

RESET

*

RESET (SOIC ONLY)

WDO (ADM699 SOIC ONLY)

WATCHDOG

TRANSITION DETECTOR

(1 sec)

TYPICAL APPLICATION CIRCUIT

+5V

WDI

*

GND

ADM698/

ADM699

RESET

µP POWER

µP SYSTEM

I/O LINE

µP RESET

FEATURES

Superior Upgrade for MAX698/MAX699

Low 0.6 mA Supply Current

Precision 4.65 V Voltage Monitor

Power OK/Reset Time Delay

Watchdog Timer

Minimum Component Count

Performance Specified over Temperature

APPLICATIONS

Microprocessor Systems

Computers

Controllers

Intelligent Instruments

Automotive Systems

Critical

P Power Monitoring

GENERAL DESCRIPTION

The ADM698/ADM699 supervisory circuits provide power

supply monitoring and watchdog timing for microprocessor

systems.

ates a RESET pulse during power up, power down and during

low voltage “Brown Out” conditions. The RESET output is

The ADM699 features an identical monitoring circuit as in the

ADM698 plus an additional watchdog timer input to monitor

microprocessor activity. The RESET output is forced low if the

watchdog input is not toggled within the 1 second watchdog

timeout period.

Both parts are available in 8-pin plastic DIP and 16-lead SOIC

packages. The 16-lead SOIC contains additional outputs

RESET

(without inversion) and Watchdog Output WDO

(ADM699 only).