Microprocessor Reset Circuits
ADM1810–ADM1813/ADM1815–ADM1818
FEATURES
Reliable Low Cost Voltage Monitor with Reset Output
Suitable for Monitoring 2.5 V, 3 V, 3.3 V, and 5 V Power
Supply Voltages
Reset Threshold Levels: 4.62 V, 4.35 V, 3.06 V, 2.88 V,
2.55 V, 2.31 V, and 2.18 V (Typ)
Active High and Low Push-Pull Output Choices
(ADM1810, ADM1812, ADM1815, and ADM1817)
Open-Drain Output Choices (ADM1811, ADM1813,
ADM1816, and ADM1818)
Can Be Used with a Manual Push-Button to Generate
a Reset (ADM1813, ADM1818)
Initialize Microprocessor Systems with Added Safety
Available in a 3-Lead SOT-23 Package
APPLICATIONS
Microprocessor Systems
Computers
Controllers
Intelligent Instruments
Automotive Systems
FUNCTIONAL BLOCK DIAGRAMS
ADM1810/ADM1815
RST
V
CC
TOLERANCE
BIAS
TC
REFERENCE
V
CC
150ms
DELAY
GND
V
CC
ADM1811/ADM1816
5.5k
RST
V
CC
TOLERANCE
BIAS
TC
REFERENCE
150ms
DELAY
GND
GENERAL DESCRIPTION
The ADM181x range of voltage monitoring circuits can be used
in any application where an electronic system needs to be reset
when a voltage increases above or below a predetermined value.
Because of the reset delay time incorporated into the ADM181x
series, these devices can provide a safe startup for electronic
systems. Before a system initializes, the power supply must stabi-
lize. Using the ADM181x series ensures that there are typically
150 ms for the power supply to stabilize before the system is reset
and safe system initialization begins.
The ADM181x series of microprocessor reset circuits are avail-
able in low cost, space-saving SOT-23 packages.
ADM1812/ADM1817
V
CC
RST
V
CC
TOLERANCE
BIAS
TC
REFERENCE
150ms
DELAY
GND
ADM1813/ADM1818
V
CC
RESET
MONITOR
V
CC
TOLERANCE
BIAS
TC
REFERENCE
5.5k
RST
150ms
DELAY
GND
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. 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.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© 2003 Analog Devices, Inc. All rights reserved.
ADM1810–ADM1813/ADM1815–ADM1818–SPECIFICATIONS
(V
CC
= Full Operating Range, T
A
= –40 C to +105 C, unless otherwise noted.)
Parameter
SUPPLY
Voltage
Current
OUTPUT CURRENT
RST
Output Source Current
RST Output Source Current
RST
Output Sink Current
8
Min
1
1.2
9
4
350
350
Typ
Max
5.5
5.5
16
10
Unit
V
V
µA
µA
µA
µA
mA
Conditions/Note
T
A
= 0˚C to 105˚C
T
A
= –40˚C to +105˚C
V
CC
= 5.5 V, V
CC
> V
TH
, No Load
V
CC
= 3.6 V, V
CC
> V
TH
, No Load
V
CC
≥
V
TH
(Max), Reset Not
Asserted (ADM1810/ADM1815)
V
CC
≤
V
TH
(Min), Reset Asserted
(ADM1812/ADM1817)
V
CC
≥
2.7 V, Reset Asserted,
V
OUT
= 0.4 V, (ADM1810/
ADM1811/ADM1813/ADM1815/
ADM1816/ADM1818)
V
CC
≥
2.7 V, Reset Not Asserted,
V
OUT
= 0.4 V (ADM1812/ADM1817)
(ADM1810/ADM1812/ADM1815/
ADM1817) @ 0
µA
to 500
µA
RST Output Sink Current
OUTPUT VOLTAGE
V
CC
TRIP POINT
ADM1810-5, ADM1811-5, ADM1812-5,
ADM1813-5
ADM1810-10, ADM1811-10,
ADM1812-10, ADM1813-10
ADM1815-5, ADM1816-5, ADM1817-5
ADM1815-10, ADM1816-10
ADM1817-10, ADM1818-10
ADM1815-20, ADM1816-20
ADM1817-20, ADM1818-20
ADM1815-R23, ADM1816-R23
ADM1817-R23
ADM1815-R22, ADM1816-R22
ADM1817-R22
INTERNAL PULL-UP RESISTOR
ADM1811/ADM1816
ADM1813/ADM1818
OUTPUT CAPACTANCE
RESET ACTIVE TIME
V
CC
DETECT TO RESET
Falling
8
V
CC
– 0.5
V
CC
– 0.1
mA
V
4.50
4.25
2.98
2.80
2.47
2.25
2.12
4.62
4.35
3.06
2.88
2.55
2.31
2.18
4.75
4.49
3.15
2.97
2.64
2.37
2.25
V
V
V
V
V
V
V
3.5
3.1
5.5
5.5
7.5
7.5
10
kΩ
kΩ
pF
ms
µs
µs
ms
µs
(ADM1810/ADM1811/ADM1812/
ADM1813)
(ADM1815/ADM1816/ADM1817/
ADM1818)
t
R
= 5
µs
(ADM1813/ADM1818)
(ADM1813/ADM1818)
100
150
5
7
250
10
15
250
Rising
PUSH-BUTTON DETECT TO
RST
PUSH-BUTTON RESET
Specifications subject to change without notice.
100
1
100
150
150
250
ms
–2–
REV. B
ADM1810–ADM1813/ADM1815–ADM1818
ABSOLUTE MAXIMUM RATINGS*
(T
A
= 25∞C, unless otherwise noted.)
PIN CONFIGURATION
RST/RST
1
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +6.0 V
Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Operating Temperature Range . . . . . . . . . . –40∞C to +105∞C
JA
Thermal Impedance, SOT-23 . . . . . . . . . . . . . . . 270∞C/W
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . 300∞C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . . 215∞C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220∞C
Storage Temperature Range . . . . . . . . . . . . –65∞C to +150∞C
*Stresses
above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum ratings
for extended periods of time may affect device reliability.
ADM181x
TOP VIEW
(Not to Scale)
V
CC
2
3 GND
PIN FUNCTION DESCRIPTIONS
Pin
1
Mnemonic
RST/RST
Function
Reset Output.
RST/RST
remains active
while V
CC
is below the reset threshold
and remains active for 150 ms (typ) after
V
CC
rises above the reset threshold.
Supply voltage being monitored.
0 V. Ground reference for all signals.
2
3
V
CC
GND
ORDERING GUIDE
Model*
ADM1810-5ART-REEL
ADM1810-5ART-RL7
ADM1810-10ART-REEL
ADM1810-10ART-RL7
ADM1811-5ART-REEL
ADM1811-5ART-RL7
ADM1811-10ART-REEL
ADM1811-10ART-RL7
ADM1812-5ART-REEL
ADM1812-5ART-RL7
ADM1812-10ART-REEL
ADM1812-10ART-RL7
ADM1813-5ART-REEL
ADM1813-5ART-RL7
ADM1813-10ART-REEL
ADM1813-10ART-RL7
ADM1815-5ART-REEL
ADM1815-5ART-RL7
ADM1815-10ART-REEL
ADM1815-10ART-RL7
ADM1815-20ART-REEL
ADM1815-20ART-RL7
ADM1815-R23ART-REEL
ADM1815-R23ART-RL7
ADM1815-R22ART-REEL
*Only
available in reels.
Trip
Point
4.62 V
4.62 V
4.35 V
4.35 V
4.62 V
4.62 V
4.35 V
4.35 V
4.62 V
4.62 V
4.35 V
4.35 V
4.62 V
4.62 V
4.35 V
4.35 V
3.06 V
3.06 V
2.88 V
2.88 V
2.55 V
2.55 V
2.31 V
2.31 V
2.18 V
Package
Option
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
Brand
Info.
MZV
MZV
MZT
MZT
M1V
M1V
M1T
M1T
MTV
MTV
MTT
MTT
M3V
M3V
M3T
M3T
M5K
M5K
M5E
M5E
M5A
M5A
M5C
M5C
M5B
Model*
ADM1815-R22ART-RL7
ADM1816-5ART-REEL
ADM1816-5ART-RL7
ADM1816-10ART-REEL
ADM1816-10ART-RL7
ADM1816-20ART-REEL
ADM1816-20ART-RL7
ADM1816-R23ART-REEL
ADM1816-R23ART-RL7
ADM1816-R22ART-REEL
ADM1816-R22ART-RL7
ADM1817-5ART-REEL
ADM1817-5ART-RL7
ADM1817-10ART-REEL
ADM1817-10ART-RL7
ADM1817-20ART-REEL
ADM1817-20ART-RL7
ADM1817-R23ART-REEL
ADM1817-R23ART-RL7
ADM1817-R22ART-REEL
ADM1817-R22ART-RL7
ADM1818-10ART-REEL
ADM1818-10ART-RL7
ADM1818-20ART-REEL
ADM1818-20ART-RL7
Trip
Point
2.18 V
3.06 V
3.06 V
2.88 V
2.88 V
2.55 V
2.55 V
2.31 V
2.31 V
2.18 V
2.18 V
3.06 V
3.06 V
2.88 V
2.88 V
2.55 V
2.55 V
2.31 V
2.31 V
2.18 V
2.18 V
2.88 V
2.88 V
2.55 V
2.55 V
Package
Option
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
RT-3 (SOT-23)
Brand
Info.
M5B
M6K
M6K
M6E
M6E
M6A
M6A
M6C
M6C
M6B
M6B
M7K
M7K
M7E
M7E
M7A
M7A
M7C
M7C
M7B
M7B
M8E
M8E
M8A
M8A
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 the
ADM1810–ADM1813/ADM1815–ADM1818 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. B
–3–
ADM1810–ADM1813/ADM1815–ADM1818–Typical Performance Characteristics
10
1.011
1.009
1.007
1.005
1.003
1.001
0.999
0.997
DEVIATION (FALL)
8
NORMALIZED RESET THRESHOLD
I
CC
@V
CC
= 5.5V
I
CC
– A
6
I
CC
@V
CC
= 3V
DEVIATION (RISE)
4
2
0
–40
–20
0
20
30
50
70
85
TEMPERATURE – C
100
120
0.995
–40
–20
0
20
30
50
70
85
TEMPERATURE – C
100
120
TPC 1. Supply Current vs. Temperature
TPC 4. Normalized Reset Threshold vs. Temperature
900
800
60
50
700
POWER-DOWN RESET DELAY –
s
MAX TRANSIENT – s
600
500
VOD = 20mV
400
300
VOD = 125mV
200
40
30
20
10
100
VOD = 200mV
0
–40
–20
0
20
30
50
70
85
TEMPERATURE – C
100
120
0
10
30
40
60
80
100
200 400
600
800 1000
V
TH
– V
CC
– mV
TPC 2. Power-Down Reset Delay vs. Temperature
TPC 5. Maximum Transient Duration without Causing
a Reset Pulse vs. Reset Comparator Overdrive
380
370
POWER-UP RESET TIMEOUT – ms
360
350
340
330
320
310
300
290
–40
–20
0
20
30
50
70
85
TEMPERATURE – C
100
120
TPC 3. Power-Up Reset Timeout vs. Temperature
–4–
REV. B
ADM1810–ADM1813/ADM1815–ADM1818
V
CC
V
CC
TRIP POINT(MAX)
V
CC
TRIP POINT
V
CC
TRIP POINT(MIN)
RST
V
CC
TO RESET
DELAY
The ADM1818 range has 2.88 V and 2.55 V (typ) trip point
options that allow the user to monitor 3.3 V and 3 V supplies. For
5 V monitoring requirements, the ADM1813 range has 4.62 V
and 4.35 V (typ) trip point options.
ADM1810, ADM1812, ADM1815, AND ADM1817
V
OL
Figure 1. Power-Down Timing Diagram
The ADM1812 is a 5 V supply monitor with an active high push-
pull output and trip point options of 4.62 V and 4.35 V (typ).
The ADM1810 is similar to the ADM1812, except that the
ADM1810 has an active low push-pull output stage.
The ADM1817 is suitable for monitoring 3.3 V, 3 V, and 2.5 V
supplies, with an active high push-pull output and trip-point
options of 3.06 V, 2.88 V, 2.55 V, 2.31 V, and 2.18 V (typ). The
ADM1815 is similar to the ADM1817, except that the ADM1815
has an active low push-pull output stage.
The ADM1810/ADM1812/ADM1815/ADM1817 can be
connected directly to most microprocessor reset inputs without
the need for external components.
V
CC
V
CC
TRIP POINT (MAX)
V
CC
TRIP POINT
V
CC
TRIP POINT (MIN)
V
CC
RESET ACTIVE TIMEOUT
RST
Figure 2. Power-Up Timing Diagram
ADM1813 AND ADM1818
ADM1810/
ADM1812/
ADM1815/
ADM1817
V
CC
RST/RST
GND
MICRO-
PROCESSOR
The ADM1813 and ADM1818 are low cost voltage monitoring
devices featuring an open-drain output and optional push-
button reset function.
V
CC
RESET
Figure 5. ADM1810/ADM1812/ADM1815/ADM1817
Typical Application
ADM1813/
ADM1818
V
CC
RST
MICRO-
PROCESSOR
RESET
ADM1811 AND ADM1816
GND
The ADM1811 is a 5 V supply monitor with an active low open-
drain output and trip point options of 4.62 V and 4.35 V (typ).
The ADM1816 also has an active low open-drain output but is
suitable for monitoring lower voltage supplies of 3.3 V, 3 V,
and 2.5 V.
V
CC
Figure 3. ADM1813/ADM1818 Typical Application
ADM1811/
ADM1816
V
CC
RST
GND
MICRO-
PROCESSOR
An optional push-button reset switch can be connected between
RST
and ground. Pressing this switch will pull the reset output
low. If the push-button reset button pulls the
RST
output low for
a period greater than 1
ms,
then, when the reset button releases
the
RST
line to float high, the
RST
line will stay low for a further
150 ms typical.
PUSH-BUTTON TIME
RESET TIMEOUT
VOLTAGE
INPUT HIGH
VOLTAGE
INPUT LOW
RESET
Figure 6. ADM1811/ADM1816 Typical Application
Figure 4. Push-Button Reset Timing Diagram
REV. B
–5–