ADM8616SBYAKSZ-RL7 [ADI]
IC,POWER SUPPLY SUPERVISOR,CMOS,TSSOP,4PIN,PLASTIC;
| 型号： | ADM8616SBYAKSZ-RL7 |
| 厂家： | 
ADI |
| 描述： | IC,POWER SUPPLY SUPERVISOR,CMOS,TSSOP,4PIN,PLASTIC |
| 文件： | 总12页 (文件大小：271K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Voltage Supervisory Circuits
with Watchdog in 4-Lead SC70
ADM8616/ADM8617
FEATURES
FUNCTIONAL BLOCK DIAGRAM
Precision 1.8 V to 5 V power supply monitoring
ADM8616
RESET
9
threshold options
1.58 V to 4.63 V
RESET
V
CC
V
CC
RESET
GENERATOR
4
timeout options
RESET
V
REF
1 ms, 20 ms, 140 ms, 1120 ms
3 watchdog timeout options
6.3 ms, 102 ms, 1.6 sec
WATCHDOG
DETECTOR
RESET
output stages
Push-pull active-low (ADM8616)
Open-drain active-low (ADM8617)
Low power consumption (5 μA)
Guaranteed reset output valid to VCC = 1 V
Power supply glitch immunity
GND
WDI
Figure 1.
Specified over −40°C to +85°C temperature range
4-lead SC70 package
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.
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.
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.
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 registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2007 Analog Devices, Inc. All rights reserved.
ADM8616/ADM8617
TABLE OF CONTENTS
Features .............................................................................................. 1
Circuit Description............................................................................8
RESET Output ...............................................................................8
Watchdog Input .............................................................................8
Application Information...................................................................9
Watchdog Input Current ..............................................................9
Negative-Going VCC Transients...................................................9
Ensuring RESET Valid to VCC = 0 V...........................................9
Watchdog Software Considerations............................................9
Outline Dimensions....................................................................... 10
Ordering Guide .......................................................................... 10
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
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
VCC = full operating range, TA = −40oC to +85oC, unless otherwise noted.
Table 1.
Parameter
Min
Typ
Max
Unit
Test Conditions/Comments
SUPPLY
VCC Operating Voltage Range
Supply Current
1
5.5
20
12
V
μA
μA
10
5
VCC = 5.5 V
VCC = 3.6 V
RESET THRESHOLD VOLTAGE
ADM861xL
ADM861xM
ADM861xT
ADM861xS
ADM861xR
ADM861xZ
ADM861xY
ADM861xW
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
4.75
4.50
3.15
3.00
2.70
2.38
2.25
1.71
1.62
V
V
V
V
V
V
V
V
ADM861xV
V
RESET THRESHOLD TEMPERATURE COEFFICIENT
ppm/°C
RESET THRESHOLD HYSTERESIS
2 × VTH
mV
RESET TIMEOUT PERIOD
ADM861xxA
ADM861xxB
ADM861xxC
ADM861xxD
1
20
140
1120
1.4
28
200
1600
40
2
40
280
2240
ms
ms
ms
ms
μs
VCC TO RESET DELAY
VCC falling at 1 mV/μs
RESET OUTPUT VOLTAGE
VOL (Open-Drain and Push-Pull)
0.3
0.3
0.3
0.4
V
V
V
V
VCC ≥ 1.0 V, ISINK = 50 μA
VCC ≥ 1.2 V, ISINK = 100 μA
VCC ≥ 2.7 V, ISINK = 1.2 mA
VCC ≥ 4.5 V, ISINK = 3.2 mA
VOH (Push-Pull Only)
0.8 × VCC
V
V
VCC ≥ 2.7 V, ISOURCE = 500 μA
VCC ≥ 4.5 V, ISOURCE = 800 μA
From 10% to 90% VCC, CL = 5 pF, VCC = 3.3 V
VCC − 1.5
RESET Rise Time
5
25
1
ns
μA
Open-Drain RESET Output Leakage Current
WATCHDOG INPUT
Watchdog Timeout Period
ADM861xxxW
ADM861xxxX
ADM861xxxY
WDI Pulse Width
WDI Input Threshold
VIL
4.3
71
1.12
50
6.3
102
1.6
9.3
153
2.4
ms
ms
sec
ns
VIL = 0.3 × VCC, VIH = 0.7 × VCC
V
0.3 × VCC
160
VIH
0.7 × VCC
V
μA
μA
WDI Input Current
120
VWDI = VCC
WDI = 0
V
−20
−15
Rev. B | Page 3 of 12
ADM8616/ADM8617
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
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.
Table 2.
Parameter
Rating
VCC
−0.3 V to +6 V
−0.3 V to +6 V
20 mA
RESET
Output Current (RESET)
Operating Temperature Range
Storage Temperature Range
θJA Thermal Impedance, SC70
Soldering Temperature
Sn/Pb
−40°C to +85°C
−65°C to +150°C
146°C/W
ESD CAUTION
240°C, 30 sec
260°C, 40 sec
Pb-Free
Rev. B | Page 4 of 12
ADM8616/ADM8617
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND
1
4
V
CC
ADM8616/
ADM8617
TOP VIEW
(Not to Scale)
RESET
2
3
WDI
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
Mnemonic Description
1
2
GND
RESET
Ground.
Active-Low RESET Output. Asserted whenever VCC is below the reset threshold (VTH).
Push-Pull Output Stage for ADM8616.
Open-Drain Output Stage for ADM8617.
3
4
WDI
VCC
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.
Rev. B | Page 5 of 12
ADM8616/ADM8617
TYPICAL PERFORMANCE CHARACTERISTICS
10.0
1.20
1.15
1.10
1.05
1.00
0.95
0.90
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
V
= 5V
CC
V
= 3.3V
CC
V
= 1.5V
CC
–40
–20
0
20
40
60
80
100
120
–40
–20
0
20
40
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 3. Supply Current vs. Temperature
Figure 6. Normalized Watchdog Timeout Period vs. Temperature
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
1.05
1.04
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
0.95
–40
–20
0
20
40
60
80
100
120
–40
–20
0
20
40
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
RESET
RESET
Threshold vs. Temperature
Figure 4. Normalized
Timeout Period vs. Temperature
Figure 7. Normalized
100
160
140
120
100
80
90
80
70
60
50
40
30
20
10
0
60
40
V
= 4.63V
CC
20
V
= 2.93V
CC
0
10
–40
–20
0
20
40
60
80
100
120
100
RESET THRESHOLD OVERDRIVE (mV)
1000
TEMPERATURE (°C)
RESET
Figure 5. VCC to
Output Delay vs. Temperature
RESET
Figure 8. Maximum VCC Transient Duration vs.
Threshold Overdrive
Rev. B | Page 6 of 12
ADM8616/ADM8617
0.20
2.92
2.90
V
= 2.9V
V
= 2.9V
CC
CC
0.15
0.10
2.88
2.86
2.84
2.82
0.05
0
0
1
2
3
4
5
6
7
0
0.2
0.4
0.6
(mA)
0.8
1.0
I
(mA)
I
SOURCE
SINK
Figure 9. Voltage Output Low vs. ISINK
Figure 10. Voltage Output High vs. ISOURCE
Rev. B | Page 7 of 12
ADM8616/ADM8617
CIRCUIT DESCRIPTION
The ADM8616/ADM8617 provide microprocessor supply
WATCHDOG INPUT
RESET
voltage supervision by controlling the microprocessors
input. Code execution errors are avoided during power-up,
power-down, and brownout conditions by asserting a
signal when the supply voltage is below a preset threshold and
by allowing supply voltage stabilization with a fixed timeout
The ADM8616/ADM8617 feature a watchdog timer that
monitors microprocessor activity. A timer circuit is cleared with
every low-to-high or high-to-low logic transition on the watch-
dog input pin (WDI), which detects pulses as short as 50 ns.
If the timer counts through the preset watchdog timeout period
RESET
RESET
after the supply voltage rises above the threshold. In
RESET
(tWD),
is asserted. The microprocessor is required to
addition, problems with microprocessor code execution can be
monitored and corrected with a watchdog timer. By including
watchdog strobe instructions in microprocessor code, a watch-
dog timer can detect if the microprocessor code breaks down or
becomes stuck in an infinite loop. If this happens, the watchdog
toggle the WDI pin to avoid being reset. Failure of the micro-
processor to toggle WDI within the timeout period, therefore,
RESET
indicates a code execution error, and the
restarts the microprocessor in a known state.
In addition to logic transitions on WDI, the watchdog timer
pulse generated
RESET
timer asserts a
a known state.
pulse that restarts the microprocessor in
RESET
condition on VCC. When
is cleared and does not begin counting again until
is also cleared by a
assertion due to an undervoltage
RESET
is asserted, the watchdog timer
RESET
RESET OUTPUT
deas-
RESET
The ADM8616 features an active-low, push-pull
output,
RESET
serts. The watchdog timer can be disabled by leaving WDI
floating or by three-stating the WDI driver.
while the ADM8617 features an active-low, open-drain
RESET
output. The
logic high, respectively, for VCC down to 1 V.
RESET
signal is guaranteed to be logic low and
V
CC
V
TH
V
CC
RESET
The
threshold (VTH), or when WDI is not serviced within the
RESET
output is asserted when VCC is below the
1V
0V
V
CC
RESET
WDI
tRP
tWD
tRD
watchdog timeout period (tWD).
remains asserted for the
active timeout period (tRP) after VCC rises
threshold or after the watchdog timer times
0V
RESET
duration of the
V
CC
RESET
above the
0V
RESET
out. Figure 11 illustrates the behavior of the
outputs.
Figure 12. Watchdog Timing Diagram
V
CC
V
V
TH
TH
V
CC
1V
0V
V
CC
RESET
tRP
RESET
tRD
0V
Figure 11.
Timing Diagram
Rev. B | Page 8 of 12
ADM8616/ADM8617
APPLICATION INFORMATION
WATCHDOG INPUT CURRENT
WATCHDOG SOFTWARE CONSIDERATIONS
In implementing the microprocessors watchdog strobe
code, quickly switching WDI low to high and then high to
low (minimizing WDI high time) is desirable for current
consumption reasons. However, a more effective way of
using the watchdog function can be considered.
To minimize watchdog input current (and minimize overall
power consumption), leave WDI low for the majority of the
watchdog timeout period. When driven high, WDI can draw as
much as 160 μA. Pulsing WDI low-high-low at a low duty cycle
reduces the effect of the large input current. When WDI is
unconnected, a window comparator disconnects the watchdog
A low-high-low WDI pulse within a given subroutine prevents
the watchdog from timing out. However, if the subroutine
becomes stuck in an infinite loop, the watchdog does not detect
this because the subroutine continues to toggle WDI. A more
effective coding scheme for detecting this error involves using a
slightly longer watchdog timeout. In the program that calls
the subroutine, WDI is set high. The subroutine sets WDI low
when it is called. If the program executes without error, WDI is
toggled high and low with every loop of the program. If the
subroutine enters an infinite loop, WDI is kept low, the watch-
dog times out, and the microprocessor is reset.
RESET
RESET
timer from the
output circuitry so that
is not asserted when the watchdog timer times out.
NEGATIVE-GOING VCC TRANSIENTS
To avoid unnecessary resets caused by fast power supply
transients, the ADM8616/ADM8617 are equipped with glitch
rejection circuitry. The typical performance characteristic in
Figure 8 plots VCC transient duration vs. transient magnitude.
The curve shows combinations of transient magnitude and
RESET
duration for which a
is not generated for 4.63 V and
2.93 V reset threshold parts. For example, with the 2.93 V
threshold, a transient that goes 100 mV below the threshold
START
RESET
and lasts 8 μs typically does not cause a
, but if the
RESET
SET WDI
HIGH
transient is any bigger in magnitude or duration, a
is
RESET
generated. An optional 0.1 μF bypass capacitor mounted close
to VCC provides additional glitch rejection.
PROGRAM
CODE
ENSURING RESET VALID TO VCC = 0 V
INFINITE LOOP:
WATCHDOG
RESET
The active-low
output is guaranteed to be valid for
TIMES OUT
VCC as low as 1 V. However, by using an external resistor,
valid outputs for VCC as low as 0 V are possible. The resistor,
SUBROUTINE
SET WDI
LOW
RESET
connected between
and ground, pulls the output low
when it is unable to sink current. A large resistance, such as
RESET
100 kΩ, should be used so that it does not overload the
output when VCC is above 1 V.
RETURN
Figure 14. Watchdog Flow Diagram
V
CC
V
CC
ADM8616/
ADM8617
RESET
RESET
RESET
µP
100kΩ
ADM8616/
ADM8617
WDI
I/O
RESET
Figure 13. Ensuring
Valid to VCC = 0 V
Figure 15. Typical Application Circuit
Rev. B | Page 9 of 12
ADM8616/ADM8617
OUTLINE DIMENSIONS
2.20
1.80
1.35
1.15
3
4
1
2.40
1.80
2
PIN 1
0.65 BSC
0.50 BSC
12°
8°
0.40
0.10
1.00
0.80
1.10
0.80
0.30
0.10
SEATING
PLANE
0.18
0.10
0.10 MAX
*
0.70
0.50
0.30
0.15
0.10 COPLANARITY
*
PACKAGE OUTLINE CORRESPONDS IN FULL TO EIAJ SC82
EXCEPT FOR WIDTH OF PIN 2 AS SHOWN.
Figure 16. 4-Lead Thin Shrink Small Outline Transistor Package [SC70]
(KS-4)
Dimensions shown in millimeters
ADM861x x x x x KSx-RL7
GENERIC NUMBER
(6/7)
ORDERING QUANTITY
RL7: 3,000 PIECE REEL
Z: LEAD FREE
RESET THRESHOLD
PACKAGE CODE
KS: 4-LEAD SC70
L: 4.63V
M: 4.38V
T: 3.08V
S: 2.93V
R: 2.63V
Z: 2.32V
Y: 2.19V
W: 1.67V
V: 1.58V
RESET TIMEOUT PERIOD
A: 1ms (MIN)
TEMPERATURE RANGE
A: –40°C TO +85°C
B: 20ms (MIN)
C: 140ms (MIN)
D: 1120ms (MIN)
WATCHDOG TIMEOUT PERIOD
W: 6.3ms (TYP)
X: 102ms (TYP)
Y: 1.6s (TYP)
Figure 17. Ordering Code Structure
ORDERING GUIDE
Reset
Threshold (V)
Package
Quantity Description
Model1
Temperature Range
−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 +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Option
KS-4
Branding
N0F
ADM8616LCYAKSZ-RL72
ADM8616MCYAKSZ-RL72
ADM8616TCYAKSZ-RL72
ADM8616SCYAKSZ-RL72
ADM8616RCYAKSZ-RL72
ADM8616ZCYAKSZ-RL72
ADM8616YCYAKSZ-RL72
ADM8616WCYAKSZ-RL72
ADM8616VCYAKSZ-RL72
ADM8617SAYAKSZ-RL72
ADM8617RCYAKSZ-RL72
4.63
3,000
3,000
3,000
3,000
3,000
3,000
3,000
3,000
3,000
3,000
3,000
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4-Lead SC70
4.38
KS-4
N0F
3.08
KS-4
N0F
2.93
KS-4
N0F
2.63
KS-4
N0F
2.32
KS-4
N0F
2.19
KS-4
N0F
1.67
KS-4
N0F
1.58
KS-4
N0F
2.93
KS-4
M4X
M4X
2.63
KS-4
1 If ordering nonstandard models, complete the ordering code shown in Figure 17 by inserting reset threshold, reset timeout, and watchdog timeout suffixes. Contact
Sales for availability of nonstandard models.
2 Z = Pb-free part.
Rev. B | Page 10 of 12
ADM8616/ADM8617
NOTES
Rev. B | Page 11 of 12
ADM8616/ADM8617
NOTES
©2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D04795-0-1/07(B)
Rev. B | Page 12 of 12
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