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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
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
( ) = ADM805L/M ONLY
ADM690A
ADM692A
ADM802L
ADM802M
ADM805L
ADM805M
POWER FAIL
OUTPUT (PFO)
RESET
(RESET)
V
OUT
V
BATT
V
CC
WATCHDOG
INPUT (WDI)
POWER FAIL
INPUT (PFI)
FEATURES
Precision Supply Voltage Monitor
4.65 V ADM690A/ADM802L/ADM805L
4.40 V ADM692A/ADM802M/ADM805M
Reset Assertion Down to 1 V V
CC
Reset Timeout—200 ms
Watchdog Timer—1.6 s
100
m
A Quiescent Supply Current
Automatic Battery Backup Power Switching
Voltage Monitor for Power Fail
6
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
μ
P 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-
tional with V
CC
as low as 1 V.
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
reliability.
RESET
assertion is guaranteed with V
CC
as low as 1 V.
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.