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a

ADM690A/ADM692A/ADM802L/M/ADM805L/M

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

Tel: 617/329-4700

World Wide Web Site: http://www.analog.com

Fax: 617/326-8703

© Analog Devices, Inc., 1996

Microprocessor

Supervisory Circuits

FUNCTIONAL BLOCK DIAGRAM

BATTERY

SWITCHOVER

RESET

GENERATOR

WATCHDOG

TRANSITION DETECTOR

(1.6s)

4.65V*

1.25V

*4.4V FOR ADM692A/ADM802M/ADM805M

ADM690A

ADM692A

ADM802L

ADM802M

ADM805L

ADM805M

POWER FAIL

OUTPUT (PFO)

RESET

WATCHDOG

INPUT (WDI)

POWER FAIL

INPUT (PFI)

(RESET)

( ) = ADM805L/M ONLY

FEATURES

Precision Supply Voltage Monitor

4.65 V ADM690A/ADM802L/ADM805L

4.40 V ADM692A/ADM802M/ADM805M

Reset Timeout—200 ms

Watchdog Timer—1.6 s

100

A Quiescent Supply Current

Automatic Battery Backup Power Switching

Voltage Monitor for Power Fail

2% Power Fail Accuracy on ADM802L/M

Space-Saving MicroSOIC Package (ADM690A)

APPLICATIONS

Microprocessor Systems

Computers

Controllers

Intelligent Instruments

GENERAL DESCRIPTION

The ADM690A/ADM692A/ADM802L/M/ADM805L/M

family of supervisory circuits offers complete single chip

solutions for power supply monitoring and battery control

functions in microprocessor systems. These functions include

µP reset, backup battery switchover, watchdog timer, and power

failure warning.

The ADM690A/ADM692A/ADM802L/M/ADM805L/M are

available in 8-pin packages and provide:

1. Power-on reset output during power-up, power-down and

brownout conditions. The RESET output remains opera-

2. Battery backup switching for CMOS RAM, CMOS

microprocessor or other low power devices.

3. A reset pulse if the optional watchdog timer has not been

toggled within 1.6 seconds.

4. A 1.25 V threshold detector for power fail warning, low battery

detection, or to monitor a power supply other than +5 V.

On the ADM690A/ADM802L/ADM805L the reset voltage

threshold is 4.65 V. On the ADM692A/ADM802M/

ADM805M, the reset voltage threshold is 4.40 V.

The ADM802L/ADM802M guarantee power fail accuracies to

±2%.

The ADM805L/M provides an active high reset output, RESET

instead of RESET.

The family of products is fabricated using an advanced epitaxial

CMOS process combining low power consumption and high

They provide a pin-compatible upgrade for the MAX690A/

MAX692A/MAX802L/MAX802M/MAX805L

All parts are available in 8-pin DIP and SOIC packages. The

ADM690A is also available in a new space-saving microSOIC

package.