ANALOG DEVICES ADM706P, ADM706R, ADM706S, ADM706T Service Manual
3 V, Voltage Monitoring
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
FEATURES
Precision supply voltage monitor
2.63 V (ADM706P, ADM706R, ADM708R)
2.93 V (ADM706S, ADM708S)
3.08 V (ADM706T, ADM708T)
100 μA quiescent current
200 ms reset pulse width
Debounced manual reset input (
MR
)
Independent watchdog timer
1.6 second timeout (ADM706x)
Reset output
Active high (ADM706P)
Active low (ADM706R, ADM706S, ADM706T)
Both active high and active low (ADM708R, ADM708S,
ADM708T)
Voltage monitor for power-fail or low battery warning
Guaranteed
RESET
valid with VCC = 1 V
Superior upgrade for MAX706P/R/S/T, MAX708R/S/T
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Critical microprocessor monitoring
Battery-operated systems
Portable instruments
Microprocessor Supervisory Circuits
FUNCTIONAL BLOCK DIAGRAMS
WATCHDOG
INPUT (WDI)
V
POWER-FAIL
INPUT (PFI)
V
POWER-FAIL
INPUT (PFI)
WATCHDOG
TRANSITIO N
DETECTOR
V
CC
70μA
MR
CC
V
*
REF
1.25V
*
VOLTAGE REFERENCE = 2.63V (P/R), 2.93V (S), 3.08V (T)
WATCHDOG
TIMER
RESET AND
WATCHDOG
TIMEBASE
RESET
GENERATOR
ADM706P/ADM706R/
ADM706S/ADM706T
Figure 1. ADM706P/ADM706R/ADM706S/ADM706T
V
CC
70μA
MR
CC
V
*
REF
1.25V
* VOLTAGE REFERENCE = 2.63V (R), 2.93V (S), 3. 08V (T)
RESET
GENERATOR
ADM708R/ADM708S/
ADM708T
Figure 2. ADM708R/ADM708S/ADM708T
WATCHD OG
OUTPUT (WDO)
RESET,
(P = RESET)
POWER-FAIL
OUTPUT (PFO)
RESET
RESET
POWER-FAIL
OUTPUT (PFO)
06435-001
06435-002
GENERAL DESCRIPTION
The ADM706P/ADM706R/ADM706S/ADM706T and the
ADM708R/ADM708S/ADM708T microprocessor supervisory
circuits are suitable for monitoring either 3 V or 3.3 V power
supplies.
The ADM706P/ADM706R/ADM706S/ADM706T provide
power-supply monitoring circuitry that generate a reset output
during power-up, power-down, and brownout conditions. The
reset output remains operational with V
Independent watchdog monitoring circuitry is also provided.
This is activated if the watchdog input has not been toggled
within 1.6 seconds.
In addition, there is a 1.25 V threshold detector for power-fail
warning, low battery detection, or to monitor an additional power
supply. An active low debounced
MR
Rev. C
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
as low as 1 V.
CC
input is also included.
The ADM706R, ADM706S, and 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.
The ADM708R/ADM708S/ADM708T provide similar functionality as the ADM706R/ADM706S/ADM706T and only differ
in that a watchdog timer function is not available. Instead, an
active high reset output (RESET) is provided in addition to the
active low (
RESET
) output.
All parts are available in narrow 8-lead PDIP and 8-lead SOIC
packages.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©1995–2008 Analog Devices, Inc. All rights reserved.
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
TABLE OF CONTENTS
Features .............................................................................................. 1
Power-Fail Reset ......................................................................... 10
Applications ....................................................................................... 1
Functional Block Diagrams ............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Typical Performance Characteristics ............................................. 8
Circuit Information ........................................................................ 10
REVISION HISTORY
5/08—Rev. B to Rev. C
Changes to Applications Section .................................................... 1
Changes to Table 2 ............................................................................ 5
Changes to Table 3 ............................................................................ 6
Changes to Figure 8 .......................................................................... 7
Changes to Figure 16 ........................................................................ 9
Manual Reset ............................................................................... 10
Watchdog Timer (ADM706x) .................................................. 10
Power-Fail Comparator ............................................................. 11
Adding Hysteresis to the Power-Fail Comparator ................. 11
RESET
Va l id
Applications Information .............................................................. 12
Monitoring Additional Supply Levels ...................................... 12
Microprocessors with Bidirectional
Outline Dimensions ....................................................................... 13
Ordering Guide .......................................................................... 14
Below 1 V VCC ..................................................... 11
RESET
........................... 12
2/07—Rev. A to Rev. B
Updated Format .................................................................. Universal
Changes to Table 1 ............................................................................ 3
Updated Outline Dimensions ....................................................... 12
Changes to Ordering Guide .......................................................... 13
Rev. C | Page 2 of 16
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
SPECIFICATIONS
VCC = 2.70 V to 5.5 V (ADM706P/ADM70xR), VCC = 3.00 V to 5.5 V (ADM70xS), VCC = 3.15 V to 5.5 V (ADM70xT), TA = T
unless otherwise noted.
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
POWER SUPPLY
VCC Operating Voltage Range 1.0 5.5 V
Supply Current 100 200 μA VCC < 3.6 V
150 350 μA VCC < 5.5 V
LOGIC OUTPUT
Reset Threshold (V
) 2.55 2.63 2.70 V ADM706P/ADM70xR
RST
2.85 2.93 3.00 V ADM70xS
3.00 3.08 3.15 V ADM70xT
Reset Threshold Hysteresis 20 mV
RESET PULSE WIDTH 160 200 280 ms ADM706P/ADM70xR, VCC = 3 V
160 200 280 ms ADM70xS/ADM70xT, VCC = 3.3 V
200 ms VCC = 5.0 V
RESET OUTPUT VOLTAGE
(ADM70xR/ADM70xS/ADM70xT)
VOH 0.8 × VCC V V
VOL 0.3 V V
VOH V
− 1.5 V V 4.5 V < VCC < 5.5 V, I
CC
VOL 0.4 V 4.5 V < VCC < 5.5 V, I
VOL 0.3 V VCC = 1 V, I
(max) < VCC < 3.6 V, I
RST
(max) < VCC < 3.6 V, I
RST
= 100 μA
SINK
SOURCE
= 3.2 mA
SINK
SOURCE
= 1.2 mA
SINK
= 800 μA
RESET OUTPUT VOLTAGE (ADM706P)
VOH V
VOL 0.3 V V
VOH V
VOL 0.4 V 4.5 V < VCC < 5.5 V, I
− 0.6 V V V
CC
− 1.5 V V 4.5 V < VCC < 5.5 V, I
CC
(max) < VCC < 3.6 V, I
RST
(max) < VCC < 3.6 V, I
RST
SOURCE
= 3.2 mA
SINK
SOURCE
= 1.2 mA
SINK
= 800 μA
RESET OUTPUT VOLTAGE (ADM708x)
VOH 0.8 × VCC V V
VOL 0.3 V V
VOH V
− 1.5 V V 4.5 V < VCC < 5.5 V, I
CC
VOL 0.4 V 4.5 V < VCC < 5.5 V, I
(max) < VCC < 3.6 V, I
RST
(max) < VCC < 3.6 V, I
RST
SOURCE
= 1.2 mA
SINK
SOURCE
= 500 μA
SINK
= 800 μA
WATCHDOG INPUT (ADM706x)
Watchdog Timeout Period 1.00 1.60 2.25 sec
WDI Pulse Width 100 ns V
ADM706P/ADM706R: V
ADM706S/ADM706T: V
V
= 0.4 V, VIH = VCC × 0.8 V
IL
(max) < VCC < 3.6 V
RST
= 3 V;
CC
= 3.3 V;
CC
50 ns 4.5 V < VCC < 5.5 V
WDI Input Threshold
VIL 0.6 V V
VIH 0.7 × VCC V V
(max) < VCC < 3.6 V
RST
(max) < VCC < 3.6 V
RST
VIL 0.8 V VCC = 5.0 V
VIH 3.5 V VCC = 5.0 V
WDI Input Current −1.0 +0.02 +1.0 μA WDI = 0 V or VCC
WDO OUTPUT VOLTAGE
VOH 0.8 × VCC V V
V
VOL 0.3 V V
0.4 V 4.5 V < VCC < 5.5 V, I
(max) < VCC < 3.6 V, I
RST
− 1.5 V V 4.5 V < VCC < 5.5 V, I
CC
(max) < VCC < 3.6 V, I
RST
SOURCE
= 1.2 mA
SINK
SOURCE
= 800 μA
= 500 μA
SINK
to T
MIN
= 500 μA
= 215 μA
= 500 μA
= 500 μA
MAX
Rev. C | Page 3 of 16
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
Parameter Min Typ Max Unit Test Conditions/Comments
MANUAL RESET INPUT
MR Pull-Up Current (MR = 0 V)
25 70 250 μA V
100 250 600 μA 4.5 V < VCC < 5.5 V
MR Pulse Width
500 ns V
150 ns 4.5 V < VCC < 5.5 V
MR INPUT THRESHOLD
VIL 0.6 V V
VIH 0.7 × VCC V V
VIL 0.8 V 4.5 V < VCC < 5.5 V
VIH 2.0 V 4.5 V < VCC < 5.5 V
MR TO RESET OUTPUT DELAY
750 ns V
250 ns 4.5 V < VCC < 5.5 V
POWER-FAIL INPUT
PFI Input Threshold 1.2 1.25 1.3 V
PFI Input Current −25 +0.01 +25 nA
PFO OUTPUT VOLTAGE
VOH 0.8 × VCC V V
VOL 0.3 V V
VOH V
− 1.5 V V 4.5 V < VCC < 5.5 V, I
CC
VOL 0.4 V 4.5 V < VCC < 5.5 V, I
(max) < VCC < 3.6 V
RST
(max) < VCC < 3.6 V
RST
(max) < VCC < 3.6 V
RST
(max) < VCC < 3.6 V
RST
(max) < VCC < 3.6 V
RST
ADM70xP/ADM70xR, V
ADM70xS/ADM70xT, V
(max) < VCC < 3.6 V, I
RST
(max) < VCC < 3.6 V, I
RST
SOURCE
SINK
= 3 V
CC
= 3.3 V, PFI falling
CC
= 500 μA
SOURCE
= 1.2 mA
SINK
= 800 μA
= 3.2 mA
Rev. C | Page 4 of 16
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
ABSOLUTE MAXIMUM RATINGS
TA = 25°C unless otherwise noted.
Table 2.
Parameter Rating
VCC −0.3 V to +6 V
All Other Inputs −0.3 V to VCC + 0.3 V
Input Current
VCC 20 mA
GND 20 mA
Digital Output Current 20 mA
Power Dissipation, N-8 (PDIP) 727 mW
θJA Thermal Impedance 135°C/W
Power Dissipation, R-8 (SOIC) 470 mW
θJA Thermal Impedance 110°C/W
Operating Temperature Range
Industrial (Version A) −40°C to +85°C
Lead Temperature (Soldering, 10 sec) 300°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
Storage Temperature Range −65°C to +150°C
ESD Rating >4.5 kV
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
Rev. C | Page 5 of 16
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