AD ADM6821 Low voltage supervisory circuits with watchdog & manual reset in 5-lead sot-23 Datasheet

Preliminary Technical Data
Low Voltage Supervisory Circuits with
Watchdog & Manual Reset in 5-Lead SOT-23
ADM6821–ADM6825
FEATURES
FUNCTIONAL BLOCK DIAGRAM
Precision Low Voltage Monitoring down to 1.8V
9 Reset Threshold Options:
1.58V to 4.63V
140ms (Min) Reset Timeout
Watchdog Timer with 1.6s Timeout
Manual Reset Input
Reset Output Stages
Push-Pull Active-Low
Open-Drain Active-Low
Push-Pull Active-High
Low Power Consumption (3µA)
Guaranteed Reset Output valid to VCC=1V
Power Supply Glitch Immunity
Specified from -40°C to +125°C
5-Lead SOT-23 Package
VCC
ADM6821
VCC
RESET
GENERATOR
VREF
MR
RESET
DEBOUNCE
WATCHDOG
DETECTOR
GND
WDI
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Portable Equipment
GENERAL DESCRIPTION
The ADM6821-ADM6825 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 9 reset threshold options
ranging from 1.58V to 4.63V. The reset and watchdog timeout
periods are fixed at 140ms (min) and 1.6s (typ), respectively.
The ADM6821-ADM6825 are available in 5-lead SOT-23
packages and typically consume only 3µA, making them
suitable for use in low power portable applications.
Table 1. Selection Table
Part No.
Watchdog Timer
Manual Reset
ADM6821
ADM6822
ADM6823
ADM6824
ADM6825
Yes
Yes
Yes
Yes
-
Yes
Yes
Yes
Yes
Output Stage
RESET
RESET
Open-Drain
Push-Pull
Push-Pull
Push-Pull
Push-Pull
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.
ADM6821–ADM6825
Preliminary Technical Data
ADM6821–ADM6825—SPECIFICATIONS
Table 2. VCC=4. 5V to 5.5V for ADM682_L/M, VCC=2.7V to 3.6V for ADM682_T/S/R, VCC=2.1V to 2.75V for ADM682_Z/Y,
VCC=1.53V to 2.0V for ADM682_W/V, TA=-40°C to +125°C, unless otherwise noted.
Parameter
SUPPLY
VCC Operating Voltage Range
Min
Typ
Max
Units
10
5.5
5.5
24
V
V
µA
30
µA
16
µA
25
µA
12
µA
20
µA
4.75
4.78
4.50
4.53
3.15
3.17
3.00
3.02
2.70
2.72
2.38
2.40
2.25
2.27
1.71
1.72
1.62
0.4
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
ppm/°C
mV
ms
ms
µs
V
0.3
V
0.3
V
0.3
V
1
1.2
Supply Current (WDI and MR unconnected)
7
5
RESET THRESHOLD VOLTAGE
ADM682_L
ADM682_M
ADM682_T
ADM682_S
ADM682_R
ADM682_Z
ADM682_Y
ADM682_W
ADM682_V
RESET THRESHOLD TEMPERATURE COEFFICIENT
RESET THRESHOLD HYSTERESIS
RESET TIMEOUT PERIOD
4.50
4.47
4.25
4.22
3.00
2.97
2.85
2.83
2.55
2.53
2.25
2.24
2.12
2.11
1.62
1.61
1.52
140
100
VCC TO RESET DELAY
RESET Output Voltage Low
RESET Output Voltage High
4.63
4.38
3.08
2.93
2.63
2.32
2.19
1.67
1.58
60
2x VTH
200
280
320
20
0.8×VCC
Rev.PrA | Page 2 of 7
V
Test Conditions/Comments
TA=0°C to +70°C
TA=--40°C to +125°C
VCC=5.5V, no load,
TA=--40°C to +85°C
VCC=5.5V, no load,
TA=--40°C to +125°C
VCC=3.6V, no load,
TA=--40°C to +85°C
VCC=3.6V, no load,
TA=--40°C to +125°C
VCC=3.6V, no load,
TA=--40°C to +85°C
(ADM6825 only)
VCC=3.6V, no load,
TA=--40°C to +125°C
(ADM6825 only)
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
TA=-40°C to +125°C
TA=-40°C to +85°C
VCC = VTH to (VTH - 100mV)
VCC>=4.25V, ISINK=3.2mA, reset
asserted
VCC>=2.55V, ISINK=1.2mA, reset
asserted
VCC>=1.25V, ISINK=100uA, reset
asserted
VCC>=1.0V, ISINK=50uA, reset
asserted, TA=-40°C to +85°C
VCC>=4.75V, ISOURCE=800uA,
reset not asserted
Preliminary Technical Data
ADM6821–ADM6825
Parameter
Min
0.8×VCC
Typ
Max
V
0.8×VCC
RESET Output Voltage High
Units
V
0.8×VCC
0.8×VCC
0.8×VCC
0.8×VCC
RESET Output Voltage Low
WATCHDOG INPUT (ADM6821-ADM6824)
Watchdog Timeout Period
WDI Pulse Width
WDI Input Threshold
VIL
VIH
WDI Input Current
1.12
50
1.6
0.3
V
0.3
V
2.40
s
ns
VIL=0.4V, VIH=0.8×VCC,
V
V
µA
µA
120
-15
VWDI= VCC, time average
VWDI=0, time average
160
0.3xVCC
V
V
µs
ns
75
k⍀
ns
0.7xVCC
1
MR Input Pulse Width
MR Glitch Rejection
MR Pull-up Resistance
MR to Reset Delay
25
ABSOLUTE MAXIMUM RATINGS
Table 3. TA = 25°C unless otherwise noted.
θJA Thermal Impedance
Lead Temperature
Soldering (10 sec)
Vapour Phase (60 sec)
Infrared (15 sec)
V
0.3xVCC
MANUAL RESET INPUT (ADM6821-ADM6823/ADM6825)
MR Input Threshold
Parameter
VCC
Output Current (RESET, RESET)
Operating Temperature Range
Storage Temperature Range
0.4
0.7xVCC
-20
Rating
-0.3V to +6V
20mA
-40°C to +125°C
-65°C to +150°C
270°C/W
100
50
200
Test Conditions/Comments
VCC>=3.15V, ISOURCE=500uA,
reset not asserted
VCC>=1.8V, ISOURCE=200uA,
reset not asserted
VCC>=4.25V, ISOURCE=800uA,
reset asserted
VCC>=2.55V, ISOURCE=500uA,
reset asserted
VCC>=1.50V, ISOURCE=100uA,
reset asserted
VCC>=1.0V, ISOURCE=1uA,
reset asserted, TA=-40°C to +85°C
VCC>=4.75V, ISINK=3.2mA,
reset not asserted
VCC>=3.15V, ISINK=1.2mA,
reset not asserted
VCC>=1.8V, ISINK=500uA,
reset not asserted
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.
300°C
215°C
220°C
Rev.PrA | Page 3 of 7
ADM6821–ADM6825
Preliminary Technical Data
PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS
5
RESET 1
GND
2
VCC
ADM6821
TOP VIEW
RESET
1
GND
2
(Not to Scale)
MR
3
RESET
1
2
4 WDI
5
VCC
MR
3
RESET
1
3
VCC
TOP VIEW
4 WDI
5
VCC
ADM6825
GND
TOP VIEW
2
(Not to Scale)
RESET
5
(Not to Scale)
ADM6824
GND
ADM6822/
ADM6823
TOP VIEW
(Not to Scale)
4 WDI
RESET
3
4 MR
Table 4. Pin Functional Descriptions
Pin No.
1
Name
RESET (ADM6822/23/24/25)
2
3
RESET (ADM6821)
GND
MR (ADM6821/22/23)
4
RESET (ADM6824/ADM6825)
WDI (ADM6821/22/23/24)
5
MR (ADM6825)
Description
Active-Low Reset Output, which is asserted whenever VCC is below the reset.threshold,
VTH.
Open-Drain Output Stage for ADM6822.
Push-Pull Output Stage for ADM6823/24/25.
Active-High Reset Output
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.
VCC
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
ADM6821–ADM6825
ORDERING GUIDE
Model
ADM6821LART-RL
ADM6821LART-RL7
ADM6821MART-RL
ADM6821MART-RL7
ADM6821TART-RL
ADM6821TART-RL7
ADM6821SART-RL
ADM6821SART-RL7
ADM6821RART-RL
ADM6821RART-RL7
ADM6821ZART-RL
ADM6821ZART-RL7
ADM6821YART-RL
ADM6821YART-RL7
ADM6821WART-RL
ADM6821WART-RL7
ADM6821VART-RL
ADM6821VART-RL7
ADM6822LART-RL
ADM6822LART-RL7
ADM6822MART-RL
ADM6822MART-RL7
ADM6822TART-RL
ADM6822TART-RL7
ADM6822SART-RL
ADM6822SART-RL7
ADM6822RART-RL
ADM6822RART-RL7
ADM6822ZART-RL
ADM6822ZART-RL7
ADM6822YART-RL
ADM6822YART-RL7
ADM6822WART-RL
ADM6822WART-RL7
ADM6822VART-RL
ADM6822VART-RL7
ADM6823LART-RL
ADM6823LART-RL7
ADM6823MART-RL
ADM6823MART-RL7
ADM6823TART-RL
ADM6823TART-RL7
ADM6823SART-RL
ADM6823SART-RL7
ADM6823RART-RL
ADM6823RART-RL7
ADM6823ZART-RL
ADM6823ZART-RL7
ADM6823YART-RL
ADM6823YART-RL7
Reset Threshold (V)
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
1.67
1.67
1.58
1.58
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
1.67
1.67
1.58
1.58
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
Temperature Range
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
Rev. PrA | Page 5 of 7
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
10k
3k
Package Type
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
Branding
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0A
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0B
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
N0C
ADM6821–ADM6825
Preliminary Technical Data
ORDERING GUIDE (CONTD.)
Model
ADM6823WART-RL
ADM6823WART-RL7
ADM6823VART-RL
ADM6823VART-RL7
ADM6824LART-RL
ADM6824LART-RL7
ADM6824MART-RL
ADM6824MART-RL7
ADM6824TART-RL
ADM6824TART-RL7
ADM6824SART-RL
ADM6824SART-RL7
ADM6824RART-RL
ADM6824RART-RL7
ADM6824ZART-RL
ADM6824ZART-RL7
ADM6824YART-RL
ADM6824YART-RL7
ADM6824WART-RL
ADM6824WART-RL7
ADM6824VART-RL
ADM6824VART-RL7
ADM6825LART-RL
ADM6825LART-RL7
ADM6825MART-RL
ADM6825MART-RL7
ADM6825TART-RL
ADM6825TART-RL7
ADM6825SART-RL
ADM6825SART-RL7
ADM6825RART-RL
ADM6825RART-RL7
ADM6825ZART-RL
ADM6825ZART-RL7
ADM6825YART-RL
ADM6825YART-RL7
ADM6825WART-RL
ADM6825WART-RL7
ADM6825VART-RL
ADM6825VART-RL7
Reset Threshold (V)
1.67
1.67
1.58
1.58
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
1.67
1.67
1.58
1.58
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
1.67
1.67
1.58
1.58
Temperature Range
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
Rev.PrA | Page 6 of 7
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
Package Type
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
Branding
N0C
N0C
N0C
N0C
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0D
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
N0E
Preliminary Technical Data
ADM6821–ADM6825
OUTLINE DIMENSIONS
2.90 BSC
5
4
2.80 BSC
1.60 BSC
1
2
3
PIN 1
0.95 BSC
1.90
BSC
1.30
1.15
0.90
1.45 MAX
0.15 MAX
0.50
0.3
0.22
0.08
SEATING
PLANE
10
5
0
COMPLIANT TO JEDEC STANDARDS MO-178AA
Figure 1. 5-Lead Small Outline Transistor Package [SOT-23]
(RT-5)
Dimensions shown in millimeters
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Printed in the U.S.A.
PR04535-0-2/04(PrA)
Rev. PrA | Page 7 of 7
0.$
0.45
0.3
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