Preliminary Technical Data
FEATURES
Supervisory Circuits with Watchdog
and Manual Reset in 5-Lead SC70 & SOT-23
ADM823–ADM825
FUNCTIONAL BLOCK DIAGRAM
V
CC
Precision 2.5V to 5V Power Supply Monitor
7 Reset Threshold Options:
2.19V to 4.63V
140ms (Min) Reset Timeout
Watchdog Timer with 1.6s Timeout (ADM823, ADM824)
Manual Reset Input (ADM823, ADM825)
Push-Pull Output Stages
RESET (ADM823)
RESET, RESET (ADM824/ADM825)
Low Power Consumption (3µA)
Guaranteed Reset Output valid to V
CC
=1V
Power Supply Glitch Immunity
Specified Over Industrial Temperature Range
5-Lead SC70 and SOT-23 Packages
ADM823
V
CC
V
REF
RESET
GENERATOR
RESET
MR
DEBOUNCE
WATCHDOG
DETECTOR
GND
WDI
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Portable Equipment
GENERAL DESCRIPTION
The ADM823-ADM825 are supervisory circuits which monitor
power supply voltage levels and code execution integrity in
microprocessor-based systems. As well as providing power on
reset signals, an on-chip watchdog timer can reset the
microprocessor if it fails to strobe within a preset timeout
period. A reset signal can also be asserted by means of an
external push-button, through a manual reset input. The three
parts feature different combinations of watchdog input, manual
reset input and output stage configuration, as shown in table 1.
Each part is available in a choice of 7 reset threshold options
ranging from 2.19V to 4.63V. The reset and watchdog timeout
periods are fixed at 140ms (min) and 1.6s (typ), respectively.
The ADM823-ADM825 are available in 5-lead SC70 and
SOT-23 packages and typically consume only 3µA, making
them suitable for use in low power portable applications.
Table 1. Selection Table
Part No.
ADM823
ADM824
ADM825
Watchdog Timer
Yes
Yes
-
Manual Reset
Yes
-
Yes
Output Stage
RESET
Push-Pull
Push-Pull
Push-Pull
RESET
-
Push-Pull
Push-Pull
Rev. PrA
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 companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
www.analog.com
Tel: 781.329.4700
Fax: 781.326.8703
© 2004 Analog Devices, Inc. All rights reserved.
ADM823–ADM825
ADM823-ADM825—SPECIFICATIONS
Preliminary Technical Data
Table 2. V
CC
=4.75V to 5.5V for ADM82_L, V
CC
=4.5V to 5.5V for ADM82_M, V
CC
=3.15V to 3.6V for ADM82_T, V
CC
=3V to 3.6V for
ADM82_S, V
CC
=2.7V to 3.6V for ADM82_R, V
CC
=2.38V to 2.75V for ADM82_Z, V
CC
=2.25V to 2.75V for ADM82_Y, T
A
=T
MIN
to
T
MAX
, unless otherwise noted
Parameter
SUPPLY
V
CC
Operating Voltage Range
Supply Current (SOT-23 only)
Min
1
1.2
10
5
Typ
Max
5.5
24
12
Units
V
V
µA
µA
Test Conditions/Comments
T
A
=0°C to +70°C
T
A
=T
MIN
to T
MAX
WDI and MR unconnected
ADM823L/M, ADM824L/M
WDI and MR unconnected
ADM823T/S/R/Z/Y,
ADM824T/S/R/Z/Y
MR unconnected
ADM825L/M
MR unconnected
ADM825T/S/R/Z/Y
WDI and MR unconnected
ADM823L/M, ADM824L/M
WDI and MR unconnected
ADM823T/S/R/Z/Y,
ADM824T/S/R/Z/Y
MR unconnected
ADM825L/M
MR unconnected
ADM825T/S/R/Z/Y
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
T
A
=+25°C
T
A
=T
MIN
to T
MAX
ADM82_L/M
ADM82_T/S/R/Z/Y
V
TH
-V
CC
=100mV
V
CC
=V
TH
min, I
SINK
=3.2mA,
ADM82_L/M
V
CC
=V
TH
min, I
SINK
=1.2mA,
ADM82_T/S/R/Z/Y
T
A
=0°C to +70°C, V
CC
=1V,
V
CC
falling, I
SINK
=50µA
V
CC
=V
TH
max, I
SOURCE
=120µA,
ADM82_L/M
4.5
3
Supply Current (SC70 only)
6
4
12
8
17
12
µA
µA
µA
µA
3
2
RESET THRESHOLD VOLTAGE
ADM82_L
ADM82_M
ADM82_T
ADM82_S
ADM82_R
ADM82_Z (SC70 only)
ADM82_Y (SC70 only)
RESET THRESHOLD TEMPERATURE COEFFICIENT
RESET THRESHOLD HYSTERESIS
RESET TIMEOUT PERIOD
V
CC
TO RESET DELAY
RESET Output Voltage
140
8
6
µA
µA
4.56
4.50
4.31
4.25
3.04
3.00
2.89
2.85
2.59
2.55
2.28
2.25
2.16
2.13
4.63
4.38
3.08
2.93
2.63
2.32
2.19
40
10
5
200
40
4.70
4.75
4.45
4.50
3.11
3.15
2.96
3.00
2.66
2.70
2.35
2.38
2.22
2.25
280
0.4
0.3
0.3
V
V
V
V
V
V
V
V
V
V
V
V
V
V
ppm/°C
mV
mV
ms
µs
V
V
V
V
V
CC
-1.5
Rev.PrA | Page 2 of 7
Preliminary Technical Data
Parameter
Min
0.8×V
CC
Typ
Max
Units
V
µA
µA
V
V
ADM823–ADM825
Test Conditions/Comments
V
CC
=V
TH
max, I
SOURCE
=30µA,
ADM82_T/S/R/Z/Y
RESET=0V, V
CC
=5.5V,
ADM82_L/M
RESET=0V, V
CC
=5.5V,
ADM82_T/S/R/Z/Y
V
CC
=V
TH
max, I
SINK
=3.2mA,
ADM824L/M, ADM825L/M
V
CC
=V
TH
max, I
SINK
=1.2mA,
ADM824T/S/R/Z/Y,
ADM825T/S/R/Z/Y
V
CC
>=1.8V, I
SOURCE
=150µA
RESET Output Short Circuit Current
800
400
RESET Output Voltage
0.4
0.3
0.8×V
CC
WATCHDOG INPUT (ADM823, ADM824)
Watchdog Timeout Period
WDI Pulse Width
WDI Input Threshold
V
IL
V
IH
WDI Input Current
MANUAL RESET INPUT (ADM823, ADM825)
MR Input Threshold
MR Input Pulse Width
MR Glitch Rejection
MR Pull-up Resistance
MR to Reset Delay
0.7xV
CC
1
35
100
52
500
75
1.12
50
1.6
2.40
V
s
ns
V
V
µA
µA
V
V
µs
ns
k
ns
V
IL
=0.4V, V
IH
=0.8×V
CC
,
0.3xV
CC
0.7xV
CC
-20
120
-15
160
V
WDI
= V
CC
, time average
V
WDI
=0, time average
0.3xV
CC
ABSOLUTE MAXIMUM RATINGS
Table 3. T
A
= 25°C unless otherwise noted.
Parameter
V
CC
Output Current (RESET, RESET)
Operating Temperature Range
SC70
SOT-23
Storage Temperature Range
θ
JA
Thermal Impedance
SC70
SOT-23
Lead Temperature
Soldering (10 sec)
Vapour Phase (60 sec)
Infrared (15 sec)
Rating
-0.3V to +6V
20mA
-40°C to +85°C
-40°C to +125°C
-65°C to +150°C
146°C/W
270°C/W
300°C
215°C
220°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and 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.
Rev.PrA | Page 3 of 7
ADM823–ADM825
PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS
RESET
GND
MR
1
ADM823
Preliminary Technical Data
5
TOP VIEW
V
CC
RESET
GND
1
ADM824
5
TOP VIEW
V
CC
RESET
GND
1
ADM825
5
TOP VIEW
V
CC
2
3
2
3
2
3
(Not to Scale)
(Not to Scale)
(Not to Scale)
4
WDI
RESET
4
WDI
RESET
4
MR
Table 4. Pin Functional Descriptions
Pin No.
1
2
3
Name
RESET
GND
MR (ADM823)
4
RESET (ADM824/ADM825)
WDI (ADM823/ADM824)
MR (ADM825)
5
V
CC
Description
Push-Pull Active-Low Reset Output, which is asserted whenever V
CC
is below the
reset.threshold, V
TH
.
Ground
Manual Reset Input. This is an active-low input which, when forced low for at least 1µs,
generates a reset.
Features a 52k internal pull-up.
Active-High, Push-Pull Reset Output.
Watchdog Input. Generates a reset if the voltage on the pin remains low or high for the
duration of the watchdog timeout. The timer is cleared if a logic transition occurs on this
pin or if a reset is generated.
Manual Reset Input.
Power Supply Voltage being Monitored
ESD 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 this product 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.
`
Rev.PrA | Page 4 of 7
Preliminary Technical Data
ORDERING GUIDE (ADM823, ADM824)
Model
ADM823LAKS-RL
ADM823LAKS-R7
ADM823LART-RL
ADM823LART-R7
ADM823MAKS-RL
ADM823MAKS-R7
ADM823MART-RL
ADM823MART-R7
ADM823TAKS-RL
ADM823TAKS-R7
ADM823TART-RL
ADM823TART-R7
ADM823SAKS-RL
ADM823SAKS-R7
ADM823SART-RL
ADM823SART-R7
ADM823RAKS-RL
ADM823RAKS-R7
ADM823RART-RL
ADM823RART-R7
ADM823ZAKS-RL
ADM823ZAKS-R7
ADM823YAKS-RL
ADM823YAKS-R7
ADM824LAKS-RL
ADM824LAKS-R7
ADM824LART-RL
ADM824LART-R7
ADM824MAKS-RL
ADM824MAKS-R7
ADM824MART-RL
ADM824MART-R7
ADM824TAKS-RL
ADM824TAKS-R7
ADM824TART-RL
ADM824TART-R7
ADM824SAKS-RL
ADM824SAKS-R7
ADM824SART-RL
ADM824SART-R7
ADM824RAKS-RL
ADM824RAKS-R7
ADM824RART-RL
ADM824RART-R7
ADM824ZAKS-RL
ADM824ZAKS-R7
ADM824YAKS-RL
ADM824YAKS-R7
Reset Threshold (V)
4.63
4.63
4.63
4.63
4.38
4.38
4.38
4.38
3.08
3.08
3.08
3.08
2.93
2.93
2.93
2.93
2.63
2.63
2.63
2.63
2.32
2.32
2.19
2.19
4.63
4.63
4.63
4.63
4.38
4.38
4.38
4.38
3.08
3.08
3.08
3.08
2.93
2.93
2.93
2.93
2.63
2.63
2.63
2.63
2.32
2.32
2.19
2.19
Temperature Range
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
Quantity
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
10k
3k
ADM823–ADM825
Package Type
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SC70-5
SC70-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SOT-23-5
SOT-23-5
SC70-5
SC70-5
SC70-5
SC70-5
Branding
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N07
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
N08
Rev. PrA | Page 5 of 7
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