a
FEATURES
Precision Supply-Voltage Monitor
+2.63 V (ADM706P/R, ADM708R)
+2.93 V (ADM706S, ADM708S)
+3.08 V (ADM706T, ADM708T)
100 A Quiescent Current
200 ms Reset Pulsewidth
Debounced Manual Reset Input (MR)
Independent Watchdog Timer—1.6 sec Timeout
(ADM706x)
Reset Output
Active High (ADM706P)
Active Low (ADM706R/S/T)
Both Active High and Active Low (ADM708R/S/T)
Voltage Monitor for Power-Fail or Low Battery Warning
Guaranteed
RESET
Valid with V
CC
= 1 V
Superior Upgrade for MAX706P/R/S/T, MAX708R/S/T
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Critical P Monitoring
Automotive Systems
Battery Operated Systems
Portable Instruments
GENERAL DESCRIPTION
+3 V, Voltage Monitoring
P Supervisory Circuits
ADM706P/R/S/T, ADM708R/S/T
FUNCTIONAL BLOCK DIAGRAMS
WATCHDOG
INPUT (WDI)
WATCHDOG
TRANSITION
DETECTOR
WATCHDOG
TIMER
WATCHDOG
OUTPUT(WDO)
V
CC
70 A
MR
RESET &
WATCHDOG
TIMEBASE
RESET
GENERATOR
RESET,
(P = RESET)
V
CC
V
REF
*
ADM706
POWER FAIL
INPUT (PFI)
1.25V
POWER FAIL
OUTPUT (PFO)
*
VOLTAGE REFERENCE = 2.63V (P/R), 2.93V (S), 3.08V (T)
V
CC
RESET
70 A
MR
RESET
GENERATOR
RESET
V
CC
V
REF
*
POWER FAIL
INPUT (PFI)
1.25V
ADM708
POWER FAIL
OUTPUT (PFO)
The ADM706P/R/S/T and the ADM708R/S/T microprocessor
supervisory circuits are suitable for monitoring either 3 V or 3.3 V
power supplies.
The ADM706P/R/S/T provide the following functions:
1. Power-supply monitoring circuitry which generates a Reset
output during power-up, power-down and brownout condi-
tions. The reset output remains operational with V
CC
as low
as 1 V.
2. Independent watchdog monitoring circuitry which is acti-
vated if the watchdog input has not been toggled within
1.6 seconds.
3. A 1.25 V threshold detector for power fail warning, low bat-
tery detection, or to monitor an additional power supply.
4. An active low debounced manual reset input (MR).
The ADM706R, ADM706S, ADM706T are identical except for
the reset threshold monitor levels which are 2.63 V, 2.93 V, and
3.08 V respectively. The ADM706P is identical to the ADM706R
in that the reset threshold is 2.63 V. It differs only in that it has
an active high reset output.
REV. A
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.
*
VOLTAGE REFERENCE = 2.63V (R), 2.93V (S), 3.08V (T)
The ADM708R/S/T provide the same functionality as the
ADM706R/S/T and only differ in that:
1. A watchdog timer function is not available.
2. An active high reset output (RESET) in addition to the
active low (RESET) output is available.
All parts are available in 8-lead DIP and narrow SOIC packages.
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
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