REV. 0

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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.

a

ADM1232A

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

Tel: 781/329-4700

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

Fax: 781/326-8703

© Analog Devices, Inc., 1999

Microprocessor

Supervisory Circuit

FUNCTIONAL BLOCK DIAGRAM

GND

PB RESET

TOLERANCE

TD

RESET

STROBE

ADM1232A

RESET

GENERATOR

RESET

DEBOUNCE

WATCHDOG

TIMEBASE

SELECT

WATCHDOG

TIMER

5%/10%

TOLERANCE

SELECT

VREF

FEATURES

Superior Upgrade for MAX1232 and Dallas DS1232

Low Power Consumption (500

A max)

Adjustable Precision Voltage Monitor with +4.5 V and

+4.75 V Options

Adjustable STROBE Monitor with 150 ms, 600 ms or

1.2 sec Options

No External Components

Fast (20 ns) Strobe Pulsewidth

APPLICATIONS

Microprocessor Systems

Portable Equipment

Computers

Controllers

Intelligent Instruments

Automotive Systems

Protection Against Damage Caused by

P Failure

GENERAL DESCRIPTION

The ADM1232A is a superior, pin-compatible upgrade for the

MAX1232 and the DS1232LP and DS1232. The ADM1232A

can detect strobe pulsewidths as narrow as 20 ns, making it

compatible with high speed microprocessors. The Analog

Devices ADM1232A is a microprocessor monitoring circuit

that can monitor:

1. Microprocessor Supply Voltage.

2. Whether a Microprocessor has locked up.

3. An External Interrupt.

The ADM1232A is available in four different packages:

1. The ADM1232AARM in an 8-lead

µSOIC (RM-8).

2. The ADM1232AAN in an 8-lead PDIP (N-8).

3. The ADM1232AARW in a 16-lead wide SOIC (R-16).

4. The ADM1232AARN is an 8-lead narrow SOIC (R-8).

ADM1232

ADM1232

STROBE

TOLERANCE

RESET

GND

TD

ADM1232A

RESET

MICROPROCESSOR

STROBE

TOLERANCE

I/O

+5V

RESET

10k

+5V

Figure 1. Typical Supply Monitoring Application