Microprocessor Supervisory
Circuit in 4-Lead SOT-143 with DSP
ADM811/ADM812
Rev. F
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 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.
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 ©2009 Analog Devices, Inc. All rights reserved.
FEATURES
Superior upgrade for MAX811/MAX812
Specified over temperature
Low power consumption: 5 μA typical
Precision voltage monitor: 2.5 V, 3 V, 3.3 V, 5 V options
Reset assertion down to 1 VCC
Power-on reset: 140 ms minimum
Logic low RESET output (ADM811)
Logic high RESET output (ADM812)
Built-in manual reset
APPLICATIONS
Microprocessor systems
Controllers
Intelligent instruments
Automotive systems
Safety systems
Portable instruments
FUNCTIONAL BLOCK DIAGRAM
RESET
GENERATOR
DEBOUNCE
V
REF
RESET/RESET
GND
V
CC
MR
ADM811/ADM812
0
0092-001
Figure 1.
GENERAL DESCRIPTION
The ADM811/ADM812 are reliable voltage monitoring devices
suitable for use in most voltage monitoring applications. The
ADM811/ADM812 are designed to monitor six different
voltages, each allowing a 5% or 10% degradation of standard
PSU voltages before a reset occurs. These voltages have been
selected for the effective monitoring of 2.5 V, 3 V, 3.3 V, and 5 V
supply voltage levels.
Included in this circuit is a debounced manual reset input.
Reset can be activated using an electrical switch (or an input
from another digital device) or by a degradation of the supply
voltage. The manual reset function is very useful, especially if
the circuit in which the ADM811/ADM812 are operating enters
into a state that can only be detected by the user. Allowing the
user to reset a system manually can reduce the damage or
danger that could otherwise be caused by an out-of-control
or locked system.
ADM811
GND
V
CC
MR RESET
MICROPROCESSOR
SYSTEM
GND
V
CC
RESET
100kΩ
0
0092-002
Figure 2. Typical ADM811 Operating Circuit
ADM811/ADM812
Rev. F | Page 2 of 12
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Circuit Information .......................................................................... 7
Reset Thresholds ...........................................................................7
Reset Output ..................................................................................7
Manual Reset ..................................................................................7
Glitch Immunity ............................................................................7
Interfacing to Other Devices ............................................................8
Output .............................................................................................8
Benefits of a Very Accurate Reset Threshold ............................8
Ensuring a Valid RESET/Reset Output Down to VCC = 0 V....8
Outline Dimensions ..........................................................................9
Ordering Guide .......................................................................... 10
REVISION HISTORY
8/09—Rev. E to Rev. F
Changes to Ordering Guide .......................................................... 10
5/08—Rev. D to Rev. E
Changes to Table 2 ............................................................................ 4
Changes to Outline Dimensions ..................................................... 9
Changes to Ordering Guide .......................................................... 10
5/06—Rev. C to Rev. D
Changes to Ordering Guide ............................................................ 9
2/03—Rev. B to Rev. C
Changes Features .............................................................................. 1
Changes to General Description .................................................... 1
Changes to Specifications ................................................................ 2
Removed Note 2 from Ordering Guide ......................................... 3
Changes to Pin Function Descriptions ........................................... 4
Removed Note from Table I ............................................................ 6
1/03—Rev. A to Rev. B
Added ADM812 ................................................................. Universal
Changes to Specifications ................................................................. 2
Changes to Ordering Guide ............................................................. 3
Changes to Pin Configuration ......................................................... 4
Changes to Pin Function Description ............................................ 4
Additions to Table I ........................................................................... 6
Changes to Manual Reset section .................................................... 6
5/02—Rev. 0 to Rev. A
Deletion of ADM812.......................................................... Universal
ADM811/ADM812
Rev. F | Page 3 of 12
SPECIFICATIONS
VCC = full operating range; TA = TMIN to TMAX; VCC typical = 5 V for L/M models, 3.3 V for T/S models, 3 V for R model, 2.5 V for Z
models, unless otherwise noted.
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
SUPPLY
Voltage 1.0 5.5 V TA = 0°C to 70°C
1.2 V TA = −40°C to +85°C
Current 8 15 μA VCC < 5.5 V, ADM81xL/M, IOUT = 0 mA
5 10 μA VCC < 3.6 V, ADM81xR/S/T/Z, IOUT = 0 mA
RESET VOLTAGE THRESHOLD
ADM81xL 4.54 4.63 4.72 V TA = 25°C
ADM81xL 4.50 4.75 V TA = −40°C to +85°C
ADM81xM 4.30 4.38 4.46 V TA = 25°C
ADM81xM 4.25 4.50 V TA = −40°C to +85°C
ADM81xT 3.03 3.08 3.14 V TA = 25°C
ADM81xT 3.00 3.15 V TA = −40°C to +85°C
ADM81xS 2.88 2.93 2.98 V TA = 25°C
ADM81xS 2.85 3.00 V TA = −40°C to +85°C
ADM81xR 2.58 2.63 2.68 V TA = 25°C
ADM81xR 2.55 2.70 V TA = −40°C to +85°C
ADM81xZ 2.28 2.32 2.35 V TA = 25°C
ADM81xZ 2.25 2.38 V TA = −40°C to +85°C
RESET THRESHOLD TEMPERATURE COEFFICIENT 30 ppm/°C
VCC TO RESET/RESET DELAY 40 μs VOD = 125 mV, ADM81xL/M
20 μs VOD = 125 mV, ADM81xR/S/T/Z
RESET ACTIVE TIMEOUT PERIOD 140 560 ms VCC = VTH(MAX)
300 700 ms ADM811-3T only
MANUAL RESET
Minimum Pulse Width 10 μs
Glitch Immunity 100 ns
RESET/RESET Propagation Delay 0.5 μs
Pull-Up Resistance 10 20 30 kΩ
The Manual Reset Circuit Acts On
An Input Rising Above 2.3 V VCC > VTH(MAX), ADM81xL/M
An Input Falling Below 0.8 V VCC > VTH(MAX), ADM81xL/M
An Input Rising Above 0.7 × VCC V VCC > VTH(MAX), ADM81xR/S/T/Z
An Input Falling Below 0.25 × VCC V VCC > VTH(MAX), ADM81xR/S/T/Z
RESET/RESET Output Voltage
Low (ADM812R/S/T/Z) 0.3 V VCC = VTH(MAX), ISINK = 1.2 mA
Low (ADM812L/M) 0.4 V VCC = VTH(MAX), ISINK = 3.2 mA
High (ADM812R/S/T/Z/L/M) 0.8 × VCC V 1.8 V < VCC < VTH(MIN), ISOURCE = 150 μA
Low (ADM811R/S/T/Z) 0.3 V VCC = VTH(MIN), ISINK = 1.2 mA
Low (ADM811L/M) 0.4 V VCC = VTH(MIN), ISINK = 3.2 mA
Low (ADM811R/S/T/Z/L/M) 0.3 V VCC > 1.0 V, ISINK = 50 μA
High (ADM811R/S/T/Z) 0.8 × VCC V VCC > VTH(MAX), ISOURCE = 500 μA
High (ADM811L/M) VCC × 1.5 V VCC > VTH(MAX), ISOURCE = 800 μA
ADM811/ADM812
Rev. F | Page 4 of 12
ABSOLUTE MAXIMUM RATINGS
Typical values are at TA = 25°C, unless otherwise noted.
Table 2.
Parameter Rating
Terminal Voltage (With Respect to Ground)
VCC −0.3 V to +6 V
All Other Inputs −0.3 V to VCC + 0.3 V
Input Current
VCC 20 mA
MR
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
20 mA
Output Current
RESET
20 mA
Power Dissipation (TA = 70°C)
RA-4 (SOT-143) 200 mW
Derate by 4 mW/°C Above 70°C
θJA Thermal Impedance 330°C/W
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +160°C
Lead Temperature (Soldering, 10 sec) 300°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
ESD Rating 3 kV
ADM811/ADM812
Rev. F | Page 5 of 12
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
ADM811/
ADM812
TOP VIEW
(Not to Scale)
GND 1
RESET/RESET 2
VCC
MR
4
3
00092-003
Figure 3. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Description
1 GND Ground Reference For All Signals, 0 V.
2 RESET (ADM811) Active Low Logic Output. RESET remains low while VCC is below the reset threshold or when MR is low;
RESET then remains low for at least 140 ms (at least 300 ms for the ADM811-3T) after VCC rises above the
reset threshold.
RESET (ADM812)
Active High Logic Output. RESET remains high while VCC is below the reset threshold or when MR is low;
RESET then remains high for 240 ms (typical) after VCC rises above the reset threshold.
3 MR Manual Reset. This active low debounced input ignores input pulses of 100 ns or less (typical) and is
guaranteed to accept input pulses of greater than 10 μs. Leave floating when not used.
4 VCC Monitored Supply Voltage of 2.5 V, 3 V, 3.3 V, or 5 V.
ADM811/ADM812
Rev. F | Page 6 of 12
TYPICAL PERFORMANCE CHARACTERISTICS
12
0
2
4
6
8
10
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
I
DD
(µA)
I
DD
@ V
CC
= 5.5V
I
DD
@ V
CC
= 3V
I
DD
@ V
CC
= 1V
00092-004
10
9
8
7
6
5
4
2
3
1
0
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
I
DD
(µA)
I
DD
@ V
CC
= 5.5V
I
DD
@ V
CC
= 3V
I
DD
@ V
CC
= 1V
00092-007
Figure 4. Supply Current vs. Temperature (ADM81xR/S/T/Z) Figure 7. Supply Current vs. Temperature (ADM81xL/M)
1000
900
800
700
600
500
400
300
200
100
0
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (µs)
V
OD
= 20mV
V
OD
= 125mV
V
OD
= 200mV
00092-005
900
800
700
600
500
400
300
200
100
0
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (µs)
V
OD
= 20mV
V
OD
= 125mV
V
OD
= 200mV
00092-008
Figure 5. Power-Down RESET Delay vs. Temperature (ADM81xR/S/T/Z) Figure 8. Power-Down RESET Delay vs. Temperature (ADM81xL/M)
299
294
279
274
269
264
259
254
249
244
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
POWER-UP RESET TIMEOUT (ms)
ADM81xL/M
ADM81xR/S/T/Z
00092-006
1.007
1.006
0.995
0.996
0.997
0.998
0.999
1.000
1.001
1.002
1.002
1.003
1.004
1.005
–40 –20 0 20 30 50 70 85 100 120
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD
00092-009
Figure 9. RESET Threshold Deviation vs. Temperature
Figure 6. Power-Up RESET Timeout vs. Temperature
ADM811/ADM812
Rev. F | Page 7 of 12
CIRCUIT INFORMATION
RESET THRESHOLDS
A reset output is provided to the microprocessor whenever the
VCC input is below the reset threshold. The actual reset threshold
depends on whether an L, M, T, S, R, or Z suffix is used (see
Table 4).
Table 4. Reset Threshold Options
Model Reset Threshold (V)
ADM811LART 4.63
ADM811MART 4.38
ADM811TART 3.08
ADM811-3TART 3.08
ADM811SART 2.93
ADM811RART 2.63
ADM811ZART 2.32
ADM812LART 4.63
ADM812MART 4.38
ADM812TART 3.08
ADM812SART 2.93
ADM812RART 2.63
ADM812ZART 2.32
RESET OUTPUT
On power-up and after VCC rises above the reset threshold, an
internal timer holds the reset output active for 240 ms (typical).
This is intended as a power-on reset signal for the processor. It
allows time for both the power supply and the microprocessor
to stabilize after power-up. If a power supply brownout or
interruption occurs, the reset output is similarly activated and
remains active for 240 ms (typical) after the supply recovers.
This allows time for the power supply and microprocessor to
stabilize.
The ADM811 provides an active low reset output (RESET)
while the ADM812 provides an active high output (RESET).
During power-down of the ADM811, the RESET output
remains valid (low) with VCC as low as 1 V. This ensures that
the microprocessor is held in a stable shutdown condition as
the supply falls and also ensures that no spurious activity can
occur via the microprocessor as it powers up.
MANUAL RESET
The ADM811/ADM812 are equipped with a manual reset
input. This input is designed to operate in a noisy environment
where unwanted glitches could be induced. These glitches could
be produced by the bouncing action of a switch contact, or where a
manual reset switch may be located some distance away from
the circuit (the cabling of which can pick up noise).
The manual reset input is guaranteed to ignore logically valid
inputs that are faster than 100 ns and to accept inputs longer in
duration than 10 μs.
GLITCH IMMUNITY
The ADM811/ADM812 contain internal filtering circuitry
providing glitch immunity from fast transient glitches on the
power supply line.
V
CC
V
REF
V
REF
V
REF
V
REF
RESET
t
1
t
1
t
1
= RESET TIME = 250ms TYPICAL
V
REF
= RESET VOLTAGE THRESHOLD
00092-010
Figure 10. Power Fall RESET Timing
ADM811/ADM812
Rev. F | Page 8 of 12
INTERFACING TO OTHER DEVICES
OUTPUT
The ADM811/ADM812 are designed to integrate with as many
devices as possible. One feature of the ADM811/ADM812 is the
reset output, which is directly proportional to VCC (this is guar-
anteed only while VCC is greater than 1 V). This enables the part
to be used with both 3 V and 5 V, or any nominal voltage within
the minimum and maximum specifications for VCC.
BENEFITS OF A VERY ACCURATE RESET
THRESHOLD
Because the ADM811/ADM812 can operate effectively even
when there are large degradations of the supply voltages, the
possibility of a malfunction during a power failure is greatly
reduced. Another advantage of the ADM811/ADM812 is its
very accurate internal voltage reference circuit. Combined,
these benefits produce an exceptionally reliable microprocessor
supervisory circuit.
ADM811
GND
V
CC
V
CC
RESET
0
0092-011
Figure 11. Ensuring a Valid RESET Output Down to VCC = 0 V
ENSURING A VALID RESET/RESET
OUTPUT DOWN TO VCC = 0 V
When VCC falls below 0.8 V, the RESET/RESET of the ADM811/
ADM812 no longer sinks current. Therefore, a high impedance
CMOS logic input connected to RESET/RESET can drift to
undetermined logic levels. To eliminate this problem, a 100 kΩ
resistor should be connected from RESET/RESET to ground.
ADM811/ADM812
Rev. F | Page 9 of 12
OUTLINE DIMENSIONS
COMPLIANT TO JEDEC STANDARDS TO-253-AA
073105-A
0.89
0.76
SEATING
PLANE
0.50
0.30
0.100
0.013
3.04
2.90
2.80
1.07
0.90
0.75
1.92 BSC
0.20
BSC
0.54 REF
12
3
4
1.40
1.30
1.20
2.64
2.10
8°
0°
0.60
0.50
0.40
0.20
0.08
1.22
0.80
Figure 12. 4-Lead Small Outline Transistor Package [SOT-143]
(RA-4)
Dimensions shown in millimeters
ADM811/ADM812
Rev. F | Page 10 of 12
ORDERING GUIDE
Model1
Reset
Threshold (V)
Tem pe ra tu re
Range
Ordering
Quantity
Package
Description
Package
Option Branding
ADM811LART-REEL 4.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBV
ADM811LART-REEL7 4.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBV
ADM811LARTZ-REEL24.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M4J
ADM811LARTZ-REEL72
4.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M4J
ADM811MART-REEL7 4.38 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBT
ADM811MARTZ-REEL2
4.38 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBT #
ADM811MARTZ-REEL72
4.38 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBT #
ADM811TART-REEL 3.08 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBG
ADM811TART-REEL7 3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBG
ADM811TARTZ-REEL2
3.08 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBG #
ADM811TARTZ-REEL72
3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBG #
ADM811-3TART-REEL7 3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MB3
ADM811-3TARTZ-RL2
3.08 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M4E
ADM811-3TARTZ-RL72
3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M4E
ADM811SART-REEL 2.93 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBE
ADM811SART-REEL7 2.93 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBE
ADM811SARTZ-REEL2
2.93 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBE #
ADM811SARTZ-REEL72
2.93 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBE #
ADM811RART-REEL7 2.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBB
ADM811RARTZ-REEL2
2.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M4N
ADM811RARTZ-REEL72
2.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M4N
ADM811ZART-REEL 2.32 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MBZ
ADM811ZART-REEL7 2.32 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MBZ
ADM811ZARTZ-REEL2
2.32 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M6G
ADM811ZARTZ-REEL72
2.32 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M6G
ADM812LART-REEL 4.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MCV
ADM812LART-REEL7 4.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCV
ADM812LARTZ-REEL2
4.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M5D
ADM812LARTZ-REEL72
4.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M5D
ADM812MART-REEL 4.38 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MCT
ADM812MART-REEL7 4.38 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCT
ADM812MARTZ-REEL2
4.38 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M6D
ADM812MARTZ-REEL72
4.38 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M6D
ADM812TART-REEL7 3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCG
ADM812TARTZ-REEL2
3.08 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M68
ADM812TARTZ-REEL72
3.08 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M68
ADM812SART-REEL 2.93 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MCE
ADM812SART-REEL7 2.93 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCE
ADM812SARTZ-REEL2
2.93 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M67
ADM812SARTZ-REEL72
2.93 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M67
ADM812RART-REEL 2.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MCB
ADM812RART-REEL7 2.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCB
ADM812RARTZ-REEL2
2.63 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M6F
ADM812RARTZ-REEL72
2.63 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M6F
ADM812ZART-REEL 2.32 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 MCZ
ADM812ZART-REEL7 2.32 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 MCZ
ADM812ZARTZ-REEL2
2.32 –40°C to +85°C 10,000 4-Lead SOT-143 RA-4 M69
ADM812ZARTZ-REEL72
2.32 –40°C to +85°C 3,000 4-Lead SOT-143 RA-4 M69
1 Available only in reels.
2 Z = RoHS Compliant Part. RoHS-compliant parts may have # branded on either the top or bottom of the device.
ADM811/ADM812
Rev. F | Page 11 of 12
NOTES
ADM811/ADM812
Rev. F | Page 12 of 12
NOTES
©2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D00092-0-8/09(F)
