ADM698 Просмотр технического описания (PDF) - Analog Devices

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ADM698

Microprocessor Supervisory Circuits

Analog Devices 

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FEATURES

Superior Upgrade for MAX698/MAX699

Guaranteed RESET Assertion with VCC = 1 V

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.

The ADM698 monitors the 5 V VCC power supply and gener-

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

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

guaranteed to be functional (logic low) with VCC as low as 1 V.

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).

Microprocessor

Supervisory Circuits

ADM698/ADM699

FUNCTIONAL BLOCK DIAGRAM

VCC

4.65V

ADM698/

ADM699

RESET

GENERATOR

WATCHDOG

INPUT

WDI*

WATCHDOG

TRANSITION DETECTOR

(1 sec)

RESET*

RESET

WATCHDOG

OUTPUT WDO*

*WDI (ADM699 ONLY)

RESET (SOIC ONLY)

WDO (ADM699 SOIC ONLY)

TYPICAL APPLICATION CIRCUIT

+5V

VCC

RESET

µP POWER

µP RESET

ADM698/

ADM699

WDI*

µP SYSTEM

I/O LINE

GND

*ADM699 ONLY

REV. 0

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

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

Tel: 617/329-4700

Fax: 617/326-8703

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