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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
ADM809/ADM810
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., 1997
Microprocessor
Supervisory Circuit in 3-Pin SOT-23
FUNCTIONAL BLOCK DIAGRAM
V
REF
V
CC
RESET
GENERATOR
240ms
ADM809/ADM810
RESET
(RESET)
GND
FEATURES
Superior Upgrade for MAX809/MAX810
Specified Over Temperature
Low Power Consumption (17 A)
Precision Voltage Monitor: +3 V, +3.3 V, +5 V Options
Reset Assertion Down to 1 V V
CC
140 ms min Power-On Reset
Logic Low
RESET Output (ADM809)
Logic High RESET Output (ADM810)
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Automotive Systems
GENERAL DESCRIPTION
The ADM809/ADM810 supervisory circuits monitor the
power supply voltage in microprocessor systems. They pro-
vide a reset output during power-up, power-down and
brownout conditions. On power-up, an internal timer holds
reset asserted for 240 ms. This holds the microprocessor in a
reset state until conditions have stabilized. The
RESET
output remains operational with V
CC
as low as 1 V. The
ADM809 provides an active low reset signal (
RESET) while
the ADM810 provides an active high signal (RESET) output.
Six reset threshold voltage options are available suitable for
monitoring a variety of supply voltages. Refer to Table I.
The reset comparator features built-in glitch immunity,
making it immune to fast transients on V
CC
.
The ADM809/ADM810 consumes only 17
A, making it
suitable for low power portable equipment. It is packaged in
a 3-pin SOT-23 package.
RESET
RESET
INPUT
GND
GND
V
CC
V
CC
P
SYSTEM
ADM809
V
CC
Figure 1. Typical Operating Circuit
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ADM809/ADM810SPECIFICATIONS
Parameter
Min
Typ
Max
Units
Test Conditions/Comments
V
CC
Operating Voltage Range
1.0
5.5
V
T
A
= 0
C to +70
C
1.2
5.5
V
T
A
= 40
C to +105
C
Supply Current
24
60
A
V
CC
< 5.5 V, ADM8_L/M, T
A
= 40
C to +85
C
17
50
A
V
CC
< 3.6 V, ADM8_R/S/T, T
A
= 40
C to +85
C
100
A
V
CC
< 5.5 V, ADM8_L/M, T
A
= +85
C to +105
C
100
A
V
CC
< 3.6 V, ADM8_R/S/T, T
A
= +85
C to +105
C
RESET THRESHOLD
Reset Voltage Threshold
ADM8_L
4.56
4.63
4.70
V
T
A
= +25
C
ADM8_L
4.5
4.75
V
T
A
= 40
C to +85
C
ADM8_L
4.40
4.86
V
T
A
= +85
C to +105
C
ADM8_M
4.31
4.38
4.45
V
T
A
= +25
C
ADM8_M
4.25
4.5
V
T
A
= 40
C to +85
C
ADM8_M
4.16
4.56
V
T
A
= +85
C to +105
C
ADM8_ J
3.93
4.00
4.06
V
T
A
= +25
C
ADM8_ J
3.89
4.10
V
T
A
= 40
C to +85
C
ADM8_ J
3.80
4.20
V
T
A
= +85
C to +105
C
ADM8_T
3.04
3.08
3.11
V
T
A
= +25
C
ADM8_T
3.00
3.15
V
T
A
= 40
C to +85
C
ADM8_T
2.92
3.23
V
T
A
= +85
C to +105
C
ADM8_S
2.89
2.93
2.96
V
T
A
= +25
C
ADM8_S
2.85
3.00
V
T
A
= 40
C to +85
C
ADM8_S
2.78
3.08
V
T
A
= +85
C to +105
C
ADM8_R
2.59
2.63
2.66
V
T
A
= +25
C
ADM8_R
2.55
2.70
V
T
A
= 40
C to +85
C
ADM8_R
2.50
2.76
V
T
A
= +85
C to +105
C
Reset Threshold Temperature Coefficient
30
ppm/
C
V
CC
to Reset Delay
20
s
V
CC
= V
TH
to (V
TH
100 mV)
Reset Active Timeout Period
140
240
560
ms
T
A
= 40
C to +85
C
100
840
ms
T
A
= +85
C to +105
C
RESET Output Voltage Low (ADM809)
0.3
V
V
CC
= V
TH
min, I
SINK
= 1.2 mA, ADM809R/S/T
0.4
V
V
CC
= V
TH
min, I
SINK
= 3.2 mA, ADM809L/M
0.3
V
V
CC
>1.0 V, I
SINK
= 50
A
RESET Output Voltage High (ADM809)
0.8 V
CC
V
V
CC
> V
TH
max, I
SOURCE
= 500
A, ADM809R/S/T
V
CC
1.5
V
V
CC
> V
TH
max, I
SOURCE
= 800
A, ADM809L/M
RESET Output Voltage Low (ADM810)
0.3
V
V
CC
= V
TH
min, I
SINK
= 1.2 mA, ADM810R/S/T
0.4
V
V
CC
= V
TH
min, I
SINK
= 3.2 mA, ADM810L/M
RESET Output Voltage High (ADM810)
0.8 V
CC
V
1.8 V < V
CC
< V
TH
min, I
SOURCE
= 150
A
(V
CC
= Full Operating Range, T
A
= T
MIN
to T
MAX
, V
CC
typ = 5 V for L/M/J, 3.3 V
for T/S, 3 V for R Models unless otherwise noted.)
ABSOLUTE MAXIMUM RATINGS*
(T
A
= +25
C unless otherwise noted)
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +6 V
RESET, RESET . . . . . . . . . . . . . . . . . . 0.3 V to Vcc + 0.5 V
Input Current
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Output Current
RESET, RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Rate of Rise, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 V/
s
Power Dissipation, RT-3 SOT-23 . . . . . . . . . . . . . . . . 320 mW
Derate by 4 mW/
C above +70
C
JA
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . 333
C/W
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
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational sections
of this specification is not implied. Exposure to absolute maximum ratings for
extended periods of time may affect device reliability.
WARNING!
ESD SENSITIVE DEVICE
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADM809/ADM810 features proprietary ESD protection circuitry, permanent damage
may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
ADM809/ADM810
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PIN FUNCTION DESCRIPTION
Pin
Mnemonic
Function
1
GND
0 V. Ground reference for all signals.
2
RESET (ADM809) Active Low Logic Output. RESET
remains low while V
CC
is below the
reset threshold, and remains low for
240 ms (typ) after V
CC
rises above
the reset threshold
2
RESET (ADM810) Active High Logic Output. RESET
remains high while V
CC
is below the
reset threshold, and remains high for
240 ms (typ) after V
CC
rises above
the reset threshold.
3
V
CC
Supply voltage being monitored.
PIN CONFIGURATION
1
2
TOP VIEW
(Not to Scale)
ADM809/
ADM810
GND
3
RESET
, RESET
V
CC
RESET
, RESET
V
CC
RESET
t1
t1
V
REF
V
REF
V
REF
V
REF
t1 = RESET TIME = 240ms TYP.
V
REF
= RESET VOLTAGE THRESHOLD
Figure 2. Power Fail Reset Timing
Table I. Reset Threshold Options
RESET
Model
Threshold
ADM809LART
4.63 V
ADM809MART
4.38 V
ADM809JART
4.00 V
ADM809TART
3.08 V
ADM809SART
2.93 V
ADM809RART
2.63 V
ADM810LART
4.63 V
ADM810MART
4.38 V
ADM810JART
4.00 V
ADM810TART
3.08 V
ADM810SART
2.93 V
ADM810RART
2.63 V
ORDERING GUIDE
Reset
Temperature
Brand
Model*
Threshold
Range
Information
Quantity
ADM809LART-REEL
4.63 V
40
C to +105
C
9LXX
10K
ADM809LART-REEL-7
4.63 V
40
C to +105
C
9LXX
3K
ADM809MART-REEL
4.38 V
40
C to +105
C
9MXX
10K
ADM809MART-REEL-7
4.38 V
40
C to +105
C
9MXX
3K
ADM809JART-REEL
4.00 V
40
C to +105
C
9JXX
10K
ADM809JART-REEL-7
4.00 V
40
C to +105
C
9JXX
3K
ADM809TART-REEL
3.08 V
40
C to +105
C
9TXX
10K
ADM809TART-REEL-7
3.08 V
40
C to +105
C
9TXX
3K
ADM809SART-REEL
2.93 V
40
C to +105
C
9SXX
10K
ADM809SART-REEL-7
2.93 V
40
C to +105
C
9SXX
3K
ADM809RART-REEL
2.63 V
40
C to +105
C
9RXX
10K
ADM809RART-REEL-7
2.63 V
40
C to +105
C
9RXX
3K
ADM810LART-REEL
4.63 V
40
C to +105
C
ALXX
10K
ADM810LART-REEL-7
4.63 V
40
C to +105
C
ALXX
3K
ADM810MART-REEL
4.38 V
40
C to +105
C
AMXX
10K
ADM810MART-REEL-7
4.38 V
40
C to +105
C
AMXX
3K
ADM810JART-REEL
4.00 V
40
C to +105
C
AJXX
10K
ADM810JART-REEL-7
4.00 V
40
C to +105
C
AJXX
3K
ADM810TART-REEL
3.08 V
40
C to +105
C
ATXX
10K
ADM810TART-REEL-7
3.08 V
40
C to +105
C
ATXX
3K
ADM810SART-REEL
2.93 V
40
C to +105
C
ASXX
10K
ADM810SART-REEL-7
2.93 V
40
C to +105
C
ASXX
3K
ADM810RART-REEL
2.63 V
40
C to +105
C
ARXX
10K
ADM810RART-REEL-7
2.63 V
40
C to +105
C
ARXX
3K
*Only available in Reels.
ADM809/ADM810
4
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TEMPERATURE C
30
0
40
20
0
20
40
60
80
25
20
15
10
5
85
V
CC
= 5V
V
CC
= 3V
V
CC
= 1V
Figure 3. Supply Current vs. Tem-
perature (ADM8_L/M/R/S/T) (No Load)
TEMPERATURE C
235
40
20
0
20
40
60
80
235.5
236
236.5
237
237.5
238
238.5
239
239.5
240
85
Figure 6. Power-Down RESET Delay
vs. Temperature ADM8_R
--Typical Performance Characteristics
TEMPERATURE C
0
40
20
0
20
40
60
80
20
40
60
80
100
120
140
160
180
200
85
V
OD
= V
TH
V
CC
V
OD
= 20mV
V
OD
= 100mV
V
OD
= 200mV
V
OD
= 10mV
Figure 4. Power-Down RESET Delay
vs. Temperature ADM8_L/M
TEMPERATURE C
0.999
40
20
0
20
40
60
80
1.002
1.0015
1.001
1.0005
1.0
0.9995
85
Figure 7. Normalized RESET Voltage
Threshold vs. Temperature
ADM8_L/M
400
350
0
1
10
1000
100
300
250
50
200
150
100
ADM8_R/S/T
RESET COMPARATOR OVERDRIVE, V
TH
V
CC
(mV)
Figure 9. Maximum Transient Dura-
tion Without Causing a RESET Pulse
vs. RESET Comparator Overdrive
TEMPERATURE C
0
40
20
0
20
40
60
80
20
40
60
80
100
120
140
160
180
85
V
OD
= V
TH
V
CC
V
OD
= 20mV
V
OD
= 100mV
V
OD
= 200mV
V
OD
= 10mV
Figure 5. Power-Down RESET Delay
vs. Temperature ADM8_T/S/R
2
1
1
RESET OUTPUT
VOLTAGE
ADM809R
ADM809T
CH1
2.00V
2.00V M 200ms CH1
2.00V
T
T
CH2
SUPPLY VOLTAGE
5V
PK TO PK
Figure 8. RESET Output Voltage vs.
Supply Voltage
ADM809/ADM810
5
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INTERFACING TO OTHER DEVICES
OUTPUT
The ADM809/ADM810 Series is designed to integrate with as
many devices as possible and therefore has a standard output
dependant on V
CC
. This enables the part to be used in both 3 V
and 5 V or any nominal voltage within the minimum and maxi-
mum specifications for V
CC
. Because of this design approach,
interfacing this device to other devices is simplified.
ENSURING A VALID RESET OUTPUT DOWN TO V
CC
= 0 V
When V
CC
falls below 0.8 V, ADM809's RESET no longer
sinks current. A high impedance CMOS logic input connected
to RESET may, therefore, drift to undetermined logic levels. To
eliminate this problem a 100 k
resistor should be connected
from RESET to ground.
V
CC
V
CC
GND
RESET
ADM809
Figure 10. Ensuring a Valid RESET Output Down to
V
CC
= 0 V
THE BENEFITS OF A VERY ACCURATE RESET
THRESHOLD
In other microprocessor supervisory circuits, tolerances in sup-
ply voltages lead to an overall increase in RESET tolerance
levels due to the deterioration of the microprocessor RESET
circuit's power supply. The possibility of a malfunction during
a power failure is greatly reduced because the ADM809 and
ADM810 series can operate effectively even when there are
large degradations of the supply voltages. Another advantage of
the ADM809 and ADM810 series is its very accurate internal
voltage reference circuit. These benefits combine to produce an
exceptionally reliable Voltage Monitor Circuit.
INTERFACING TO MICROPROCESSORS WITH
MULTIPLE INTERRUPTS
In a number of cases it is necessary to interface many interrupts
from different devices (i.e., thermal, attitude and velocity sen-
sors). The ADM809 and ADM810 can easily be integrated into
existing interrupt-handling circuits (Figure 11) or used as a
stand-alone device.
PRIORITY ENCODER
74LS147
4 LINE BCD
TO
P
V
CC
ADM809
GND
RESET
OTHER SENSING
DEVICES
V
CC
Figure 11. Interfacing to
Ps with Multiple Interrupts
ADM809/ADM810
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OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
C3047124/97
PRINTED IN U.S.A.
Surface Mount Package
RT-3
0.1200 (3.048)
0.1102 (2.799)
PIN 1
0.0550 (1.397)
0.0470 (1.194)
0.0236 (0.599)
0.0177 (0.450)
0.1040 (2.642)
0.0827 (2.101)
0.0413 (1.049)
0.0374 (0.950)
0.0807 (2.050)
0.0701 (1.781)
1
2
3
SEATING
PLANE
0.0440 (1.118)
0.0320 (0.813)
0.0040 (0.102)
0.0005 (0.013)
0.0210 (0.533)
0.0146 (0.371)
0.027 (0.686)
REF
0.0059 (0.150)
0.0034 (0.086)
0.0100 (0.254)
0.0050 (0.127)
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