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.
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
V
CC
5%/10%
TOLERANCE
SELECT
VREF
FEATURES
Superior Upgrade for MAX1232 and Dallas DS1232
Low Power Consumption (500 mA 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 mP 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 m SOIC (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
STROBE
TOLERANCE
RESET
GND TD
ADM1232A
RESET
MICROPROCESSOR
STROBE
TOLERANCE
I/O
+5V
RESET
10kV
+5V
Figure 1. Typical Supply Monitoring Application