Low Voltage Supervisory Circuits
with Watchdog in 4-Lead SC70
ADM8616/ADM8617
FEATURES
Precision 1.8 V to 5 V power supply monitoring
9 RESET threshold options
1.58 V to 4.63 V
4 RESET timeout options
1 ms, 20 ms, 140 ms, 1120 ms
3 watchdog timeout options
6.3 ms, 102 ms, 1.6 sec
RESET output stages
Push-pull active-low (ADM8616)
Open-drain active-low (ADM8617)
Low power consumption (5 μA)
Guaranteed reset output valid to V
CC
= 1 V
Power supply glitch immunity
Specified over
−40°C
to +85°C temperature range
4-lead SC70 package
FUNCTIONAL BLOCK DIAGRAM
ADM8616
V
CC
V
CC
V
REF
RESET
GENERATOR
RESET
WATCHDOG
DETECTOR
04795-001
GND
WDI
Figure 1.
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Portable equipment
GENERAL DESCRIPTION
The ADM8616/ADM8617 are supervisory circuits that monitor
power supply voltage levels and code execution integrity in
microprocessor-based systems. A power-on reset signal is
generated when the supply voltage rises to a preset threshold
level. The ADM8616/ADM8617 have an on-chip watchdog
timer that can reset the microprocessor if it fails to strobe
within a preset timeout period.
Each part is available in the following nine reset threshold
options: 1.58 V, 1.67 V, 2.19 V, 2.32 V, 2.63 V, 2.93 V, 3.08 V,
4.38 V, and 4.63 V. There are four reset timeout options: 1 ms,
20 ms, 140 ms, and 1120 ms. There are also three possible
watchdog timeouts available: 6.3 ms, 102 ms, and 1.6 sec.
The parts differ in terms of reset output configuration. The
ADM8616 is active-low with a push-pull output, while the
ADM8617 is active-low with an open-drain output.
The ADM8616/ADM8617 are available in 4-lead SC70 packages
and typically consume only 5 μA, making them suitable for use
in low power, portable applications.
Rev. B
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
©2007 Analog Devices, Inc. All rights reserved.
ADM8616/ADM8617
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 Description............................................................................8
RESET Output ...............................................................................8
Watchdog Input .............................................................................8
Application Information...................................................................9
Watchdog Input Current ..............................................................9
Negative-Going V
CC
Transients ...................................................9
Ensuring RESET Valid to V
CC
= 0 V ...........................................9
Watchdog Software Considerations............................................9
Outline Dimensions ....................................................................... 10
Ordering Guide .......................................................................... 10
REVISION HISTORY
1/07—Rev. A to Rev. B
Changes to Functional Block Diagram.......................................... 1
11/06—Rev. 0 to Rev. A
Changes to Ordering Guide .......................................................... 10
6/05—Revision 0: Initial Version
Rev. B | Page 2 of 12
ADM8616/ADM8617
SPECIFICATIONS
V
CC
= full operating range, T
A
= −40
o
C to +85
o
C, unless otherwise noted.
Table 1.
Parameter
SUPPLY
V
CC
Operating Voltage Range
Supply Current
RESET THRESHOLD VOLTAGE
ADM861xL
ADM861xM
ADM861xT
ADM861xS
ADM861xR
ADM861xZ
ADM861xY
ADM861xW
ADM861xV
RESET THRESHOLD TEMPERATURE COEFFICIENT
RESET THRESHOLD HYSTERESIS
RESET TIMEOUT PERIOD
ADM861xxA
ADM861xxB
ADM861xxC
ADM861xxD
V
CC
TO RESET DELAY
RESET OUTPUT VOLTAGE
VOL (Open-Drain and Push-Pull)
1
20
140
1120
Min
1
10
5
4.50
4.25
3.00
2.85
2.55
2.25
2.12
1.62
1.52
4.63
4.38
3.08
2.93
2.63
2.32
2.19
1.67
1.58
40
2 × V
TH
1.4
28
200
1600
40
2
40
280
2240
Typ
Max
5.5
20
12
4.75
4.50
3.15
3.00
2.70
2.38
2.25
1.71
1.62
Unit
V
μA
μA
V
V
V
V
V
V
V
V
V
ppm/°C
mV
ms
ms
ms
ms
μs
V
V
V
V
V
V
ns
μA
Test Conditions/Comments
V
CC
= 5.5 V
V
CC
= 3.6 V
V
CC
falling at 1 mV/μs
V
CC
≥ 1.0 V, I
SINK
= 50 μA
V
CC
≥ 1.2 V, I
SINK
= 100 μA
V
CC
≥ 2.7 V, I
SINK
= 1.2 mA
V
CC
≥ 4.5 V, I
SINK
= 3.2 mA
V
CC
≥ 2.7 V, I
SOURCE
= 500 μA
V
CC
≥ 4.5 V, I
SOURCE
= 800 μA
From 10% to 90% V
CC
, C
L
= 5 pF, V
CC
= 3.3 V
0.3
0.3
0.3
0.4
0.8 × V
CC
V
CC
−
1.5
5
25
1
VOH (Push-Pull Only)
RESET Rise Time
Open-Drain RESET Output Leakage Current
WATCHDOG INPUT
Watchdog Timeout Period
ADM861xxxW
ADM861xxxX
ADM861xxxY
WDI Pulse Width
WDI Input Threshold
VIL
VIH
WDI Input Current
4.3
71
1.12
50
6.3
102
1.6
9.3
153
2.4
ms
ms
sec
ns
V
V
μA
μA
V
IL
= 0.3 × V
CC
, V
IH
= 0.7 × V
CC
0.3 × V
CC
0.7 × V
CC
−20
120
−15
160
V
WDI
= V
CC
V
WDI
= 0
Rev. B | Page 3 of 12
ADM8616/ADM8617
ABSOLUTE MAXIMUM RATINGS
T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter
V
CC
RESET
Output Current (RESET)
Operating Temperature Range
Storage Temperature Range
θ
JA
Thermal Impedance, SC70
Soldering Temperature
Sn/Pb
Pb-Free
Rating
−0.3
V to +6 V
−0.3
V to +6 V
20 mA
−40°C
to +85°C
−65°C
to +150°C
146°C/W
240°C, 30 sec
260°C, 40 sec
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 12
ADM8616/ADM8617
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND
1
ADM8616/
ADM8617
TOP VIEW
(Not to Scale)
4
V
CC
RESET
2
3
WDI
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
1
2
Mnemonic
GND
RESET
Description
Ground.
Active-Low RESET Output. Asserted whenever V
CC
is below the reset threshold (V
TH
).
Push-Pull Output Stage for ADM8616.
Open-Drain Output Stage for ADM8617.
Watchdog Input. Generates a RESET if the logic level 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. Leave
floating to disable the watchdog timer.
Power Supply Voltage Being Monitored.
3
WDI
4
V
CC
Rev. B | Page 5 of 12
04795-002
Microcontroller MCU
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