3 V, Voltage Monitoring
Microprocessor Supervisory Circuits
Data Sheet
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 sec timeout (ADM706P,
ADM706R, ADM706S,
ADM706T)
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 V
CC
= 1 V
Superior upgrade for MAX706P/R/S/T, MAX708R/S/T
WATCHDOG
INPUT (WDI)
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
FUNCTIONAL BLOCK DIAGRAMS
WATCHDOG
TRANSITION
DETECTOR
V
CC
70μA
MR
V
CC
V
REF
*
POWER-FAIL
INPUT (PFI)
1.25V
WATCHDOG
TIMER
RESET AND
WATCHDOG
TIMEBASE
RESET,
(P = RESET)
WATCHDOG
OUTPUT (WDO)
RESET
GENERATOR
ADM706P/ADM706R/
ADM706S/ADM706T
* VOLTAGE REFERENCE = 2.63V (P/R), 2.93V (S), 3.08V (T)
Figure 1.
ADM706P/ADM706R/ADM706S/ADM706T
V
CC
70μA
MR
V
CC
V
REF
*
POWER-FAIL
INPUT (PFI)
RESET
GENERATOR
RESET
RESET
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Critical microprocessor monitoring
Battery operated systems
Portable instruments
ADM708R/ADM708S/
ADM708T
* VOLTAGE REFERENCE = 2.63V (R), 2.93V (S), 3.08V (T)
Figure 2.
ADM708R/ADM708S/ADM708T
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
CC
as low as 1 V.
Independent watchdog monitoring circuitry is also provided. This
activates if the watchdog input does not toggle within 1.6 sec.
In addition, there is a 1.25 V threshold detector for a power fail
warning, low battery detection, or to monitor an additional
power supply. An active low debounced MR 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 functio-
nality 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 devices are available in narrow 8-lead PDIP and 8-lead
SOIC packages.
Rev. E
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06435-002
1.25V
POWER-FAIL
OUTPUT (PFO)
06435-001
POWER-FAIL
OUTPUT (PFO)
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
TABLE OF CONTENTS
Features .............................................................................................. 1
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
Power Fail Reset .......................................................................... 10
Data Sheet
Manual Reset............................................................................... 10
Watchdog Timer (ADM706P/ADM706R/
ADM706S/ADM706T) .............................................................. 10
Power Fail Comparator.............................................................. 11
Adding Hysteresis to the Power Fail Comparator ................. 11
Valid RESET Below 1 V V
CC
..................................................... 11
Applications Information .............................................................. 12
Monitoring Additional Supply Levels...................................... 12
Microprocessors with Bidirectional RESET ........................... 12
Outline Dimensions ....................................................................... 13
Ordering Guide .......................................................................... 14
REVISION HISTORY
1/16—Rev. D to Rev. E
Changes to Table 3 ............................................................................ 6
Changes to Table 4 ............................................................................ 7
Changes to Power Fail Comparator Section, Figure 17,
and Figure 18 ................................................................................... 10
Changes to Figure 20 and Figure 22 ............................................. 12
Changes to Ordering Guide .......................................................... 14
10/14—Rev. C to Rev. D
Changes to Pin 4 Description; Table 3 ........................................... 6
Changes to Pin 4 Description; Table 4 ........................................... 7
Changes to Ordering Guide .......................................................... 14
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
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. E | Page 2 of 16
Data Sheet
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
SPECIFICATIONS
V
CC
= 2.70 V to 5.5 V (ADM706P/ADM706R/ADM708R), V
CC
= 3.00 V to 5.5 V (ADM70xS), V
CC
= 3.15 V to 5.5 V (ADM70xT), T
A
=
T
MIN
to T
MAX
unless otherwise noted.
Table 1.
Parameter
POWER SUPPLY
V
CC
Operating Voltage Range
Supply Current
LOGIC OUTPUT
Reset Threshold (V
RST
)
Min
1.0
100
150
2.55
2.85
3.00
160
160
2.63
2.93
3.08
20
200
200
200
RESET OUTPUT VOLTAGE (ADM706R/ADM708R/
ADM706S/ADM708S/ADM706T/ADM708T)
V
OH
V
OL
V
OH
V
OL
V
OL
RESET OUTPUT VOLTAGE (ADM706P)
V
OH
V
OL
V
OH
V
OL
RESET OUTPUT VOLTAGE
(ADM708R/ADM708S/ADM708T)
V
OH
V
OL
V
OH
V
OL
WATCHDOG INPUT (ADM706P/ADM706R/
ADM706S/ADM706T)
Watchdog Timeout Period
WDI Pulse Width
WDI Input Threshold
V
IL
V
IH
V
IL
V
IH
WDI Input Current
Typ
Max
5.5
200
350
2.70
3.00
3.15
280
280
Unit
V
μA
μA
V
V
V
mV
ms
ms
ms
Test Conditions/Comments
V
CC
< 3.6 V
V
CC
< 5.5 V
ADM706P/ADM706R/ADM708R
ADM706S/ADM708S
ADM706T/ADM708T
ADM706P/ADM706R/ADM708R,
V
CC
= 3 V
ADM706S/ADM708S/ADM706T/ADM708T,
V
CC
= 3.3 V
V
CC
= 5.0 V
Reset Threshold Hysteresis
RESET PULSE WIDTH
0.8 × V
CC
0.3
V
CC
− 1.5 V
0.4
0.3
V
CC
− 0.6 V
0.3
V
CC
− 1.5 V
0.4
V
V
V
V
V
V
V
V
V
V
RST
(max) < V
CC
< 3.6 V, I
SOURCE
= 500 μA
V
RST
(max) < V
CC
< 3.6 V, I
SINK
= 1.2 mA
4.5 V < V
CC
< 5.5 V, I
SOURCE
= 800 μA
4.5 V < V
CC
< 5.5 V, I
SINK
= 3.2 mA
V
CC
= 1 V, I
SINK
= 100 μA
V
RST
(max) < V
CC
< 3.6 V, I
SOURCE
= 215 μA
V
RST
(max) < V
CC
< 3.6 V, I
SINK
= 1.2 mA
4.5 V < V
CC
< 5.5 V, I
SOURCE
= 800 μA
4.5 V < V
CC
< 5.5 V, I
SINK
= 3.2 mA
0.8 × V
CC
0.3
V
CC
− 1.5 V
0.4
V
V
V
V
V
RST
(max) < V
CC
< 3.6 V, I
SOURCE
= 500 μA
V
RST
(max) < V
CC
< 3.6 V, I
SINK
= 500 μA
4.5 V < V
CC
< 5.5 V, I
SOURCE
= 800 μA
4.5 V < V
CC
< 5.5 V, I
SINK
= 1.2 mA
1.00
100
50
1.60
2.25
sec
ns
ns
ADM706P/ADM706R:
V
CC
= 3 V;
ADM706S/ADM706T:
V
CC
= 3.3 V;
V
IL
= 0.4 V, V
IH
= V
CC
× 0.8 V
V
RST
(max) < V
CC
< 3.6 V
4.5 V < V
CC
< 5.5 V
V
RST
(max) < V
CC
< 3.6 V
V
RST
(max) < V
CC
< 3.6 V
V
CC
= 5.0 V
V
CC
= 5.0 V
WDI = 0 V or V
CC
0.6
0.7 × V
CC
0.8
3.5
−1.0
+0.02
+1.0
V
V
V
V
μA
Rev. E | Page 3 of 16
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
Parameter
WDO OUTPUT VOLTAGE
V
OH
V
OL
MANUAL RESET INPUT
MR Pull-Up Current (MR = 0 V)
MR Pulse Width
MR INPUT THRESHOLD
V
IL
V
IH
V
IL
V
IH
MR TO RESET OUTPUT DELAY
POWER FAIL INPUT
PFI Input Threshold
PFI Input Current
PFO OUTPUT VOLTAGE
V
OH
V
OL
V
OH
V
OL
Min
0.8 × V
CC
V
CC
− 1.5 V
0.3
0.4
25
100
500
150
70
250
250
600
Typ
Max
Unit
V
V
V
V
μA
μA
ns
ns
V
V
V
V
ns
ns
V
nA
V
V
V
V
Data Sheet
Test Conditions/Comments
V
RST
(max) < V
CC
< 3.6 V, I
SOURCE
= 500 μA
4.5 V < V
CC
< 5.5 V, I
SOURCE
= 800 μA
V
RST
(max) < V
CC
< 3.6 V, I
SINK
= 500 μA
4.5 V < V
CC
< 5.5 V, I
SINK
= 1.2 mA
V
RST
(max) < V
CC
< 3.6 V
4.5 V < V
CC
< 5.5 V
V
RST
(max) < V
CC
< 3.6 V
4.5 V < V
CC
< 5.5 V
V
RST
(max) < V
CC
< 3.6 V
V
RST
(max) < V
CC
< 3.6 V
4.5 V < V
CC
< 5.5 V
4.5 V < V
CC
< 5.5 V
V
RST
(max) < V
CC
< 3.6 V
4.5 V < V
CC
< 5.5 V
ADM706P/ADM706R/ADM708R,
V
CC
= 3 V
ADM706S/ADM708S/ADM706T/ADM708T,
V
CC
= 3.3 V, PFI falling
0.6
0.7 × V
CC
0.8
2.0
750
250
1.2
−25
0.8 × V
CC
0.3
V
CC
− 1.5 V
0.4
1.25
+0.01
1.3
+25
V
RST
(max) < V
CC
< 3.6 V, I
SOURCE
= 500 μA
V
RST
(max) < V
CC
< 3.6 V, I
SINK
= 1.2 mA
4.5 V < V
CC
< 5.5 V, I
SOURCE
= 800 μA
4.5 V < V
CC
< 5.5 V, I
SINK
= 3.2 mA
Rev. E | Page 4 of 16
Data Sheet
ADM706P/ADM706R/ADM706S/ADM706T, ADM708R/ADM708S/ADM708T
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ABSOLUTE MAXIMUM RATINGS
T
A
= 25°C unless otherwise noted.
Table 2.
Parameter
V
CC
All Other Inputs
Input Current
V
CC
GND
Digital Output Current
Power Dissipation, N-8 (PDIP)
θ
JA
Thermal Impedance
Power Dissipation, R-8 (SOIC)
θ
JA
Thermal Impedance
Operating Temperature Range
Industrial (Version A)
Lead Temperature (Soldering, 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
Storage Temperature Range
ESD Rating
Rating
−0.3 V to +6 V
−0.3 V to V
CC
+ 0.3 V
20 mA
20 mA
20 mA
727 mW
135°C/W
470 mW
110°C/W
−40°C to +85°C
300°C
215°C
220°C
−65°C to +150°C
>4.5 kV
ESD CAUTION
Rev. E | Page 5 of 16
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