Microprocessor Reset Circuits
ADM1810 to ADM1813/ADM1815 to 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 typical
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
Initialization of microprocessor systems with added safety
Available in 3-lead SOT-23 and SC70 packages
V
CC
FUNCTIONAL BLOCK DIAGRAMS
ADM1810/ADM1815
RST
V
CC
TOLERANCE
BIAS
150ms
DELAY
GND
TC
REFERENCE
ADM1811/ADM1816
V
CC
5.5kΩ
RST
V
CC
TOLERANCE
BIAS
150ms
DELAY
GND
TC
REFERENCE
APPLICATIONS
Microprocessor systems
Computers
Controllers
Intelligent instruments
Automotive systems
GENERAL DESCRIPTION
The ADM181x range of voltage monitoring circuits is 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 provide a safe startup for electronic systems.
Before a system initializes, the power supply must stabilize.
Using the ADM181x series ensures that there are typically 150 ms
for the power supply to stabilize before the system resets and
safe system initialization begins.
The ADM181x series of microprocessor reset circuits are
available in low cost, space-saving SOT-23 and SC70 packages.
V
CC
ADM1812/ADM1817
RST
V
CC
TOLERANCE
BIAS
150ms
DELAY
GND
TC
REFERENCE
ADM1813/ADM1818
V
CC
RESET
MONITOR
V
CC
TOLERANCE
BIAS
5.5kΩ
RST
150ms
DELAY
00064-001
GND
TC
REFERENCE
Figure 1.
Rev. E
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ADM1810 to ADM1813/ADM1815 to ADM1818
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagrams ............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution .................................................................................. 4
Pin Configurations and Function Descriptions ........................... 5
Typical Performance Characteristics ..............................................6
Theory of Operation ...........................................................................7
Timing Diagrams for All Devices ...............................................7
ADM1813 and ADM1818..............................................................7
ADM1810, ADM1812, ADM1815, and ADM1817 .....................7
ADM1811 and ADM1816..............................................................7
Outline Dimensions ..........................................................................8
Ordering Guide .............................................................................9
REVISION HISTORY
8/08—Rev. D to Rev. E
Changes to Table 3 ............................................................................ 5
Updated Outline Dimensions ......................................................... 8
Changes to Ordering Guide ............................................................ 9
10/05—Rev. C to Rev. D
Updated Format .................................................................. Universal
Added Figure 3 .................................................................................. 5
Changes to Table 3 ............................................................................ 5
Updated Outline Dimensions ......................................................... 8
Editsto Ordering Guide ................................................................... 9
9/03—Rev. B to Rev. C.
Added SC70 ......................................................................... Universal
Edits to Specifications ...................................................................... 2
Edits to Ordering Guide .................................................................. 4
Updated Outline Dimensions ......................................................... 7
2/03—Rev. A to Rev. B
.
Edits to Features.................................................................................1
Deleted Table I ...................................................................................1
Edits to Specifications .......................................................................2
Edits to Absolute Maximum Ratings ..............................................3
Edits to Ordering Guide ...................................................................3
Added Typical Performance Characteristics .................................4
Edits to ADM1813 AND ADM1818 section .................................5
Edits to ADM1810, ADM1812, ADM1815, and
ADM1817 Section .............................................................................5
Edits to ADM1811 and ADM1816 Section ...................................5
Updated Outline Dimensions ..........................................................6
3/02—Rev. 0 to Rev. A.
Addition of Table ..............................................................................1
Edits to Ordering Guide ...................................................................3
Addition of New Text to ADM1813 and ADM1818 Section ......4
4/99—Rev.0: Initial Version
Rev. E | Page 2 of 16
ADM1810 to ADM1813/ADM1815 to ADM1818
SPECIFICATIONS
V
CC
= full operating range, T
A
= −40°C to +105°C, unless otherwise noted.
Table 1.
Parameter
SUPPLY
Voltage
Current
OUTPUT CURRENT
RST Output Source Current
RST Output Source Current
RST Output Sink Current
Min
1
1.2
9
4
350
350
8
Typ
Max
5.5
5.5
16
10
Unit
V
V
μA
μA
μA
μA
mA
Comments
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,
ADM1818-5
ADM1815-10, ADM1816-10,
ADM1817-10, ADM1818-10
ADM1815-20, ADM1816-20,
ADM1817-20, ADM1818-20
ADM1815-R23, ADM1816-R23,
ADM1817-R23, ADM1818-R23
ADM1815-R22, ADM1816-R22,
ADM1817-R22, ADM1818-R22
INTERNAL PULL-UP RESISTOR
ADM1811/ADM1816
ADM1813/ADM1818
OUTPUT CAPACITANCE
RESET ACTIVE TIME
V
CC
DETECT TO RESET
Falling
Rising
PUSH-BUTTON DETECT TO RST
PUSH-BUTTON RESET
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
100
5.5
5.5
150
10
150
150
7.5
7.5
10
250
kΩ
kΩ
pF
ms
μs
ms
μs
ms
100
1
100
250
250
t
R
= 5 μs
(ADM1813/ADM1818)
(ADM1813/ADM1818)
Rev. E | Page 3 of 16
ADM1810 to ADM1813/ADM1815 to ADM1818
ABSOLUTE MAXIMUM RATINGS
T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter
V
CC
Input Current
Operating Temperature Range
Storage Temperature Range
θ
JA
Thermal Impedance, SOT-23
θ
JA
Thermal Impedance, SC70
Lead Temperature (Soldering, 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
Rating
−0.3 V to +6.0 V
20 mA
−40°C to +105°C
−65°C to +150°C
270°C/W
146°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; 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. E | Page 4 of 16
ADM1810 to ADM1813/ADM1815 to ADM1818
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
RST/RST
1
V
CC 1
ADM181x
3
GND
TOP VIEW
(Not to Scale)
00064-002
ADM181x
3
GND
TOP VIEW
(Not to Scale)
00064-014
V
CC 2
RST/RST
2
Figure 2. 3-Lead SOT-23 Pin Configuration
Figure 3. 3-Lead SC70 Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
SOT-23 SC70
1
2
Mnemonic
RST
Function
Active High Reset Output. RST remains high while V
CC
is below the reset
threshold and remains high for 150 ms typical after V
CC
rises above the reset
threshold. Applies to the ADM1812 and ADM1817 only.
Active Low Reset Output. RST remains low while V
CC
is below the reset threshold
and remains low for 150 ms typical after V
CC
rises above the reset threshold.
Applies to the ADM1810, ADM1811, ADM1813, ADM1815, ADM1816, and
ADM1818 only.
Supply Voltage. The supply voltage being monitored.
Ground. 0 V ground reference for all signals.
RST
2
3
1
3
V
CC
GND
Rev. E | Page 5 of 16
