Microprocessor
Supervisory Circuit
ADM1232
APPLICATIONS
FUNCTIONAL BLOCK DIAGRAM
VCC
TOLERANCE
5%/10%
TOLERANCE
SELECT
VREF
PB RESET
DEBOUNCE
TD
WATCHDOG
TIME-BASE
SELECT
RESET
RESET
WATCHDOG
TIMER
STROBE
07522-001
Pin-compatible with MAX1232 and Dallas DS1232
Adjustable precision voltage monitor with 4.5 V and
4.75 V options
Adjustable strobe monitor with 150 ms, 600 ms, or
1.2 sec options
No external components
Specified from −40°C to +85°C
RESET
GENERATOR
FEATURES
ADM1232
GND
Figure 1.
Microprocessor systems
Portable equipment
Computers
Controllers
Intelligent instruments
Automotive systems
GENERAL DESCRIPTION
5V
The ADM1232 is pin-compatible with the MAX1232, DS1232LP,
and DS1232. The Analog Devices, Inc., ADM1232 is a microprocessor monitoring circuit that can monitor the following:
Microprocessor supply voltage
Whether a microprocessor has locked up
External interrupts
The ADM1232 is available in four packages: an 8-lead MSOP
(RM-8), an 8-lead PDIP (N-8), a 16-lead wide SOIC (RW-16),
and an 8-lead narrow SOIC (R-8).
10kΩ
ADM1232
STROBE
RESET
GND
MICROPROCESSOR
I/O
RESET
TD TOLERANCE
07522-002
•
•
•
5V
Figure 2. Typical Supply Monitoring Application
Rev. C
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 ©1997–2008 Analog Devices, Inc. All rights reserved.
ADM1232
TABLE OF CONTENTS
Features .............................................................................................. 1
Pin Configurations and Function Descriptions ............................5
Applications ....................................................................................... 1
Circuit Information ...........................................................................6
Functional Block Diagram .............................................................. 1
PB RESET .......................................................................................6
General Description ......................................................................... 1
STROBE Timeout Selection.........................................................6
Revision History ............................................................................... 2
Tolerance ........................................................................................6
Specifications..................................................................................... 3
RESET and RESET Outputs .........................................................6
Absolute Maximum Ratings............................................................ 4
Outline Dimensions ..........................................................................7
Thermal Resistance ...................................................................... 4
Ordering Guide .............................................................................9
ESD Caution .................................................................................. 4
REVISION HISTORY
12/08—Rev. B to Rev. C
Updated Format .................................................................. Universal
Changes to Table 2 ............................................................................ 4
Added Thermal Resistance Section ............................................... 4
Updated Outline Dimensions ......................................................... 7
Changes to Ordering Guide ............................................................ 9
12/97—Rev. A to Rev. B
Changes to Specifications Section .................................................. 2
x/97—Rev. 0 to Rev. A
Changes to Specifications Section .................................................. 2
7/97—Revision 0: Initial Version
Rev. C | Page 2 of 12
ADM1232
SPECIFICATIONS
VCC = full operating range, TA = TMIN to TMAX, unless otherwise noted.
Table 1.
Parameter
TEMPERATURE
POWER SUPPLY
Voltage
Current
Min
−40
Typ
Max
+85
Unit
°C
Test Conditions/Comments
TA = TMIN to TMAX.
4.5
5.0
20
200
5.5
50
500
V
μA
μA
VIL, VIH = CMOS levels.
VIL, VIH = TTL levels.
VCC + 0.3
+0.8
V
V
+1.0
1.6
μA
μA
STROBE AND PB RESET INPUTS
Input High Level
Input Low Level
INPUT LEAKAGE CURRENT
(STROBE, TOLERANCE)
TD
OUTPUT CURRENT
RESET
RESET/RESET
8
−8
10
−12
mA
mA
VCC is at 4.5 V to 5.5 V.
VCC is at 4.5 V to 5.5 V.
OUTPUT VOLTAGE
RESET/RESET
VCC − 0.5
VCC − 0.1
V
When sourcing less than 500 μA, RESET remains within
0.5 V of VCC on power-down until VCC drops below 2.0 V.
When sinking less than 500 μA, RESET remains within
0.5 V of GND on power-down until VCC drops below 2.0 V.
RESET/RESET High Level
RESET/RESET Low Level
2.0
−0.3
−1.0
0.4
2.4
1 V OPERATION
RESET Output Voltage
RESET Output Voltage
VCC TRIP POINT
5%
10%
CAPACITANCE
Input (STROBE, TOLERANCE)
Output (RESET, RESET)
VCC − 0.1
0.1
4.5
4.25
4.62
4.37
V
V
V
V
When sourcing less than 50 μA.
When sinking less than 50 μA.
4.74
4.49
V
V
TOLERANCE = GND.
TOLERANCE = VCC.
5
7
pF
pF
TA = 25°C.
TA = 25°C.
ms
PB RESET must be held low for a minimum of 20 ms to
guarantee a reset.
PB RESET
Time
20
Delay
RESET ACTIVE TIME
1
250
4
610
20
1000
ms
ms
70
62.5
250
500
150
600
1200
250
1000
2000
ns
ms
ms
ms
STROBE
Pulse Width
Timeout Period
VCC
Fall Time
Rise Time
VCC FAIL DETECT TO RESET
OUTPUT DELAY
10
0
250
610
50
1000
TD = 0 V.
TD = floating.
TD = VCC.
μs
μs
Guaranteed by design.
Guaranteed by design.
RESET and RESET are logically correct.
μs
ms
After VCC falls below the set tolerance voltage (see Figure 9).
After VCC rises above the set tolerance voltage.
Rev. C | Page 3 of 12
ADM1232
ABSOLUTE MAXIMUM RATINGS
TA = 25°C unless otherwise noted.
THERMAL RESISTANCE
Table 2.
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Parameter
VCC
Logic Inputs
Storage Temperature Range
Lead Temperature (Soldering, 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
Power Dissipation
N-81
RW-16, RM-82
R-82
1
2
Rating
5.5 V
−0.3 V to VCC + 0.3 V
−65°C to +150°C
300°C
215°C
220°C
1000 mW
900 mW
900 μW
Table 3. Thermal Resistance
Package Type
8-Lead PDIP (N-8)
16-Lead SOIC_W (RW-16)
8-Lead MSOP (RM-8)
8-Lead SOIC_N (R-8)
ESD CAUTION
Derate by 13.5 mW/°C above 25°C.
Derate by 12 mW/°C above 25°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.
Rev. C | Page 4 of 12
θJA
100
73
206
153
Unit
°C/W
°C/W
°C/W
°C/W
ADM1232
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
NC 1
16 NC
PB RESET 2
TD 4
NC 5
ADM1232
14 NC
13 STROBE
TOP VIEW
(Not to Scale) 12 NC
TOLERANCE 6
11 RESET
NC 7
10 NC
GND 8
9
RESET
NC = NO CONNECT
07522-003
NC 3
15 VCC
PB RESET 1
TD 2
ADM1232
TOLERANCE 3
TOP VIEW
(Not to Scale)
GND 4
8
VCC
7
STROBE
6
RESET
5
RESET
07522-004
Figure 3. RW-16 Pin Configuration
PB RESET 1
TD 2
ADM1232
TOLERANCE 3
TOP VIEW
(Not to Scale)
GND 4
8
VCC
7
STROBE
6
RESET
5
RESET
07522-005
Figure 4. RM-8 Pin Configuration
Figure 5. N-8 and R-8 Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
N-8, R-8,
RM-8
RW-16
1, 3, 5, 7,
10, 12,
14, 16
2
1
Mnemonic
NC
Description
No Connection.
PB RESET
4
2
TD
6
3
TOLERANCE
8
9
4
5
GND
RESET
11
13
6
7
RESET
STROBE
15
8
VCC
Push-Button Reset Input. This debounced input ignores pulses of less than 1 ms and is
guaranteed to respond to pulses greater than 20 ms.
Time Delay Set. This input allows the user to select the maximum amount of time that the
ADM1232 allows the STROBE input to remain inactive—that is, STROBE is not receiving any
high-to-low transitions—without forcing the ADM1232 to generate a RESET pulse.
See the Specifications section, Figure 8, and the STROBE Timeout Selection section.
Tolerance Input. This input determines how much the supply voltage is allowed to decrease (as a
percentage) before a RESET is asserted. Connect this pin to VCC for 10% and to GND for 5%.
0 V Ground Reference for All Signals.
Active High Logic Output. This pin is asserted when any of the following events occurs:
VCC decreases below the amount specified by the TOLERANCE input; when PB RESET is forced low;
if there are no high-to-low transitions within the limits set by TD at STROBE; and during power-up.
Inverse of RESET. This pin has an open-drain output.
The STROBE input is used to monitor the activity of a microprocessor. If there are no high-to-low
transitions within the time specified by TD, a reset is asserted.
Power Supply Input, 5 V.
Rev. C | Page 5 of 12
ADM1232
CIRCUIT INFORMATION
PB RESET
STROBE TIMEOUT SELECTION
The PB RESET input makes it possible to manually reset a
system using either a standard push-button switch or a logic
low input. An internal debounce circuit provides glitch
immunity when used with a switch, reducing the effects of
glitches on the line. The debounce circuit is guaranteed to cause
the ADM1232 to assert a reset if PB RESET is brought low for
more than 20 ms and is guaranteed to ignore low inputs of less
than 1 ms.
TD (time delay) set is used to set the strobe timeout period. The
strobe timeout period is the maximum time between high-tolow transitions that STROBE accepts before a reset is asserted
(see Figure 8). The strobe timeout settings are listed in Table 5.
VCC
VCC
Min
62.5
250
500
Typ
150
600
1200
Max
250
1000
2000
Unit
ms
ms
ms
STROBE
PULSE WIDTH
MICROPROCESSOR
STROBE
RESET
I/O
STROBE
RESET
STROBE TIMEOUT PERIOD
Figure 8. STROBE Parameters
Figure 6. Typical Push-Button Reset Application
VCC
PB RESET TIME
VIL
5V
4.5V (5% TRIP POINT)
5V
4.25V (10% TRIP POINT)
VIH
RESET OUTPUT DELAY
WHEN VCC IS RISING
RESET OUTPUT DELAY
WHEN VCC IS FALLING
RESET ACTIVE
TIME
RESET
RESET
07522-009
PB RESET
DELAY
PB RESET
07522-008
TOLERANCE
07522-006
GND
Condition
TD = 0 V
TD = Floating
TD = VCC
TD
ADM1232
PB RESET
Table 5. Strobe Timeout Settings
07522-007
RESET
RESET
Figure 7. PB RESET
Figure 9. Reset Output Delay
TOLERANCE
The TOLERANCE input is used to determine the level at which
VCC can vary below 5 V without the ADM1232 asserting a reset.
Connecting TOLERANCE to GND selects a −5% tolerance level
and causes the ADM1232 to generate a reset if VCC falls below
4.75 V. If TOLERANCE is connected to VCC, a −10% tolerance
level is selected, which causes the ADM1232 to generate a reset
if VCC falls below 4.5 V. See the parameters for the VCC trip point
in the Specifications section for more information.
RESET AND RESET OUTPUTS
RESET is capable of sourcing and sinking current, whereas
RESET is an open-drain MOSFET that sinks current only.
Therefore, it is necessary to pull this output high.
Rev. C | Page 6 of 12
ADM1232
OUTLINE DIMENSIONS
10.50 (0.4134)
10.10 (0.3976)
9
16
7.60 (0.2992)
7.40 (0.2913)
10.65 (0.4193)
10.00 (0.3937)
8
1.27 (0.0500)
BSC
0.30 (0.0118)
0.10 (0.0039)
COPLANARITY
0.10
0.75 (0.0295)
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
SEATING
PLANE
0.51 (0.0201)
0.31 (0.0122)
8°
0°
1.27 (0.0500)
0.40 (0.0157)
0.33 (0.0130)
0.20 (0.0079)
COMPLIANT TO JEDEC STANDARDS MS-013- AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 10. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body
(RW-16)
Dimensions shown in millimeters and (inches)
3.20
3.00
2.80
8
3.20
3.00
2.80
1
5
5.15
4.90
4.65
4
PIN 1
0.65 BSC
0.95
0.85
0.75
1.10 MAX
0.15
0.00
0.38
0.22
COPLANARITY
0.10
45°
0.23
0.08
8°
0°
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 11. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
Rev. C | Page 7 of 12
0.80
0.60
0.40
032707-B
1
ADM1232
0.400 (10.16)
0.365 (9.27)
0.355 (9.02)
8
5
1
4
0.280 (7.11)
0.250 (6.35)
0.240 (6.10)
0.100 (2.54)
BSC
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.060 (1.52)
MAX
0.210 (5.33)
MAX
0.015
(0.38)
MIN
0.150 (3.81)
0.130 (3.30)
0.115 (2.92)
SEATING
PLANE
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
0.195 (4.95)
0.130 (3.30)
0.115 (2.92)
0.015 (0.38)
GAUGE
PLANE
0.430 (10.92)
MAX
0.005 (0.13)
MIN
0.014 (0.36)
0.010 (0.25)
0.008 (0.20)
0.070 (1.78)
0.060 (1.52)
0.045 (1.14)
070606-A
COMPLIANT TO JEDEC STANDARDS MS-001
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 12. 8-Lead Plastic Dual In-Line Package [PDIP]
Narrow Body
(N-8)
Dimensions shown in inches and (millimeters)
5.00 (0.1968)
4.80 (0.1890)
8
1
5
6.20 (0.2441)
5.80 (0.2284)
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
SEATING
PLANE
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
0.50 (0.0196)
0.25 (0.0099)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-012-A A
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 13. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
Rev. C | Page 8 of 12
012407-A
4.00 (0.1574)
3.80 (0.1497)
ADM1232
ORDERING GUIDE
Model
ADM1232ARM
ADM1232ARM-REEL
ADM1232ARM-REEL7
ADM1232ARMZ 1
ADM1232ARMZ-REEL1
ADM1232ARMZ-REEL71
ADM1232AN
ADM1232ANZ1
ADM1232ARW
ADM1232ARW-REEL
ADM1232ARW-REEL7
ADM1232ARWZ1
ADM1232ARWZ-REEL1
ADM1232ARWZ-REEL71
ADM1232ARN
ADM1232ARN-REEL
ADM1232ARN-REEL7
ADM1232ARNZ1
ADM1232ARNZ-REEL1
ADM1232ARNZ-REEL71
1
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
−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 Description
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
8-Lead Plastic Dual In-Line Package [PDIP]
8-Lead Plastic Dual In-Line Package [PDIP]
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
16-Lead Standard Small Outline Package [SOIC_W], Wide Body
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
Z = RoHS Compliant Part.
Rev. C | Page 9 of 12
Package
Options
RM-8
RM-8
RM-8
RM-8
RM-8
RM-8
N-8
N-8
RW-16
RW-16
RW-16
RW-16
RW-16
RW-16
R-8
R-8
R-8
R-8
R-8
R-8
Branding
M2A
M2A
M2A
M4W
M4W
M4W
ADM1232
NOTES
Rev. C | Page 10 of 12
ADM1232
NOTES
Rev. C | Page 11 of 12
ADM1232
NOTES
©1997–2008 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07522-0-12/08(C)
Rev. C | Page 12 of 12