Microprocessor
Supervisory Circuit
ADM809-5L/ADM809-5S
FEATURES
Specified over temperature
Low power consumption: 17 μA
Precision voltage monitor: 3 V, 5 V options
Reset assertion down to 1 V V
CC
30 ms minimum power-on reset
Logic low RESET output
Available in SOT-23 and SC70 packages
FUNCTIONAL BLOCK DIAGRAM
ADM809-5L/
ADM809-5S
V
CC
V
REF
RESET
GENERATOR
55ms
RESET
GND
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Automotive systems
Figure 1.
GENERAL DESCRIPTION
The supervisory circuit of the ADM809-5L/ADM809-5S monitors
the power supply voltage in microprocessor systems. It provides
a reset output during power-up, power-down, and brownout
conditions. On power-up, an internal timer holds reset asserted
for 55 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 ADM809-5L/ADM809-5S provide
an active low reset signal (RESET).
The reset comparator features built-in glitch immunity, making
it immune to fast transients on V
CC
.
The ADM809-5L/ADM809-5S consume only 17 μA, making
them suitable for low power, portable equipment.
V
CC
TYPICAL OPERATING CIRCUIT
V
CC
V
CC
ADM809-5L/
ADM809-5S
RESET
GND
MICROPROCESSOR
SYSTEM
RESET INPUT
00090-002
GND
Figure 2.
Rev. B
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rights of third parties that may result from its use. Specifications subject to change without notice. No
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©2008 Analog Devices, Inc. All rights reserved.
00090-001
ADM809-5L/ADM809-5S
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Typical Operating Circuit ................................................................ 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions..............................5
Typical Performance Characteristics ..............................................6
Theory of Operation .........................................................................7
Interfacing to Output of Other Devices .....................................7
Ensuring a Valid Reset Output Down to V
CC
= 0 V .................7
Benefits of a Very Accurate RESET Threshold .............................7
Interfacing to Microprocessors with Multiple Interrupts ........7
Outline Dimensions ..........................................................................8
Ordering Guide .............................................................................8
REVISION HISTORY
10/08—Rev. A to Rev. B
Updated Format .................................................................. Universal
Updated Outline Dimensions ......................................................... 8
Changes to Ordering Guide ............................................................ 8
3/03—Rev. 0 to Rev. A
Added SC70 Package .......................................................... Universal
Changes to Features ......................................................................... 1
Changes to Specifications ............................................................... 2
Changes to Absolute Maximum Ratings ...................................... 2
Changes to Table I .......................................................................... 3
Changes to Ordering Guide ........................................................... 3
Changes to TPC 2 ............................................................................ 4
Updated Outline Dimensions ........................................................ 6
Rev. B | Page 2 of
8
ADM809-5L/ADM809-5S
SPECIFICATIONS
V
CC
= full operating range, T
A
= T
MIN
to T
MAX
, V
CC
typical = 5 V for L models and 3.3 V for S models, unless otherwise noted.
Table 1.
Parameter
POWER SUPPLY
V
CC
Operating Voltage Range
Min
1.0
1.2
Typ
3.3
3.3
24
17
4.5
4.40
2.85
2.78
30
20
55
Max
5.5
5.5
60
50
4.75
4.86
3.00
3.08
Unit
V
V
μA
μA
V
V
V
V
ppm/°C
μs
ms
V
V
V
V
V
°C
V
CC
= V
TH
to (V
TH
− 100 mV)
T
A
= −40°C to +150°C
V
CC
= V
TH
minimum, I
SINK
= 1.2 mA, ADM809-5S
V
CC
= V
TH
minimum, I
SINK
= 3.2 mA, ADM809-5L
V
CC
>1.0 V, I
SINK
= 50 μA, T
A
= 0°C to 150°C
V
CC
>1.2 V, I
SINK
= 50 μA, T
A
= −40°C to +150°C
V
CC
> V
TH
maximum, I
SOURCE
= 500 μA
V
CC
> V
TH
maximum, I
SOURCE
= 800 μA
Test Conditions/Comments
T
A
= 0°C to 150°C with 100 kΩ pull-down on output (Figure 10)
T
A
= −40°C to +150°C with 22 kΩ external pull-up on output
(Figure 13)
V
CC
< 5.5 V, ADM809-5L, T
A
= −40°C to +150°C
V
CC
< 3.6 V, ADM809-5S, T
A
= −40°C to +150°C
T
A
= −40°C to +85°C
T
A
= 85°C to 150°C
T
A
= −40°C to +85°C
T
A
= 85°C to 150°C
Supply Current
RESET VOLTAGE THRESHOLD
ADM809-5L
ADM809-5L
ADM809-5S
ADM809-5S
RESET THRESHOLD TEMPERATURE
COEFFICIENT
V
CC
TO RESET DELAY
RESET ACTIVE TIMEOUT PERIOD
RESET OUTPUT VOLTAGE
RESET Output Voltage Low
30
80
0.3
0.4
0.3
RESET Output Voltage High
JUNCTION TEMPERATURE
0.8 V
CC
V
CC
− 1.5
−40
+150
Rev. B | Page 3 of
8
ADM809-5L/ADM809-5S
ABSOLUTE MAXIMUM RATINGS
T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter
V
CC
RESET
Input Current
V
CC
Output Current
RESET
Rate of Rise, V
CC
θ
JA
Thermal Impedance
SOT-23
SC70
Lead Temperature (Soldering, 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
Storage Temperature Range
Rating
−0.3 V to +6 V
−0.3 V to V
CC
+ 0.5 V
20 mA
20 mA
100 V/μs
270°C/W
146°C/W
300°C
215°C
220°C
−65°C to +150°C
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. B | Page 4 of
8
ADM809-5L/ADM809-5S
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND 1
ADM809-5L/
ADM809-5S
TOP VIEW
(Not to Scale)
3 V
CC
00090-003
RESET 2
Figure 3. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
1
2
3
Mnemonic
GND
RESET
V
CC
Function
Ground Reference for All Signals (0 V).
Active Low Logic Output. RESET remains low while V
CC
is below the reset threshold, and remains low for
55 ms (typical) after V
CC
rises above the reset threshold.
Supply Voltage Being Monitored.
V
CC
V
REF
V
REF
V
REF
V
REF
RESET
t
1
t
1
Figure 4. Power Fail RESET Timing
Table 4. RESET Threshold Options
Model
ADM809-5L
ADM809-5S
RESET Threshold (V)
4.63
2.93
Rev. B | Page 5 of
8
00090-004
NOTES
1.
t
1
= RESET TIME = 55ms TYPICAL.
2. V
REF
= RESET VOLTAGE THRESHOLD.
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