The ASM1233M is a voltage supervisor with low-power, 5V µP
Reset, with an active LOW, open-drain output. Maximum supply
current over temperature is a low 20µA.
The ASM1233M generates an active LOW reset signal
whenever the monitored supply is out of tolerance. A precision
reference and comparator circuit monitor power supply (V
level. Tolerance level options are 5% ,and 10% for a 5V power
supply. The tolerance is 15% for the 3.3V, ASM1233M. When
an out-of-tolerance condition is detected, an internal power-fail
signal is generated which forces an active LOW reset signal.
After V
remains active for 350ms to allow the power supply and system
microprocessor to stabilize.
The ASM1233M is designed with a open-drain output stage and
operates over the extended industrial temperature range.
Devices are available in compact surface mount SO-8
packages and 3-lead TO-92 packages.
returns to an in-tolerance condition, the reset signal
CC
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
CC
Applications
•Set-top boxes
•Cellular phones
•PDAs
•Energy management systems
•Embedded control systems
•Printers
•Single board computers
)
Typical Operating Circuit
V
CC
ASM1233M
RESET
ASM1233M
Microprocessor
RESET
Other low power products in this family include the ASM1810/
11/12/15/16/17 and ASM1233D.
Key Features
•Low Supply Current
•20 µA maximum (5.5 V)
•15µA maximum (3.6 V)
•Automatically restarts a microprocessor after power failure
•350ms reset delay after V
dition
•Active LOW power-up reset, 5kΩ internal pull-up
•Precision temperature-compensated voltage reference and
comparator
•Eliminates external components
•Low-cost TO-92 package
•Compact surface mount SO-8 package
•Operating temperature -40°C to +85°C
returns to an in-tolerance con-
CC
Alliance Semiconductor
2575 Augustine Drive . Santa Clara, CA 95054 . Tel: 408.855.4900 . Fax: 408.855.4999 . www.alsc.com
Notice: The information in this document is subject to change without notice
GND
Block Diagram
V
CC
2
ASM1233M
5.0kΩ
Supply
Tolerance
Bias
Delay
+
+
-
-
Reference
Delay
150ms
150ms
Typical
Typical
GND
4
1
RESET
Page 2
October 2003
rev 1.0
Pin Configuration
ASM1233M
RESET
V
CC
NC
GND
Pin Description
Pin #
SO-8TO-92
11RESETActive LOW reset output
22
SO-8
1
2
3
4
8
NC
NC
7
NC
6
ASM1233M-X
NC
5
Pin NameDescription
V
CC
Power supply input
TO-92*
ASM1233M-X
2
1
3
3, 5, 6, 7 and 8-NCNo Connection.
43GNDGround.
* See Ordering Information
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
2 of 9
Page 3
October 2003
rev 1.0
Application Information
Operation - Power Monitor
The ASM1233M detects out-of-tolerance power supply
conditions. It resets a processor during power-up, power-
down and generates a reset to the system processor when
the monitored power supply voltage is below the reset
threshold. When an out-of-tolerance V
the RESET signal is asserted. On power-up, RESET is kept
active (LOW) for approximatley 350ms after the power supply
voltage has reached the selected tolerance. This allows the
power supply and microprocessor to stablize before RESET
is released.
t
(MIN)
V
CCTP
voltage is detected,
CC
R
V
CCTP
V
CCTP
(MAX)
t
V
CCTP
F
t
RPD
V
OL
V
CC
V
(MAX)
CCTP
RESET
Figure 2: Timing Diagram: Power-Down
ASM1233M
V
(MIN)
CCTP
~
~
~
~
V
CC
~
RESET
Figure 1: Timing Diagram: Power-Up
~
t
RPU
V
OH
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
3 of 9
Page 4
October 2003
rev 1.0
Absolute Maximum Ratings
ParameterMinMaxUnit
ASM1233M
Voltage on V
Voltage on RESET-0.5VCC + 0.5V
Operating Temperature Range-4085°C
Soldering Temperature (for 10 sec)260°C
Storage Temperature-55125°C
NOTE: These are stress ratings only and functional use is not implied. Exposure to absolute maximum ratings for prolonged periods of time may affect device reliability.
CC
-0.57V
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
4 of 9
Page 5
October 2003
ASM1233M
rev 1.0
Electrical Characteristics
Unless otherwise noted, VCC = 1.2V to 5.5V and specifications are over the operating temperature range of -40°C to +85°C.
All voltages are referenced to ground.
ParameterSymbolConditionsMinTypMaxUnit
Supply Voltage
Output Voltage
Output Current
Operating Current
Operating Current
V
Trip Point (ASM1233M-5)V
CC
VCC Trip Point (ASM1233M-55)V
VCC Trip Point (ASM1233M-3)V
Voltage High Trip Level
ASM1233M-5
ASM1233M-55
Voltage Low Trip Level
ASM1233M-5
ASM1233M-55
Voltage High Trip Level
ASM1233M-3
V
CC
V
OH
I
OL
I
CC
I
CC
CCTP
CCTP
CCTP
V
HTL
V
LTL
V
HTL
1.25.5V
I
< 500 µAVCC - 0.5VVCC - 0.1V
OUT
Output = 0.4V, VCC >= 2.7V
VCC < 5.5V, RESET output open
VCC < =3.6V, RESET output
open
+8mA
4.254.3754.49V
4.54.6254.75V
2.642.722.8V
V
820µA
615µA
4.75
4.00V
3.14V
V
C
R
OUT
RPD
t
F
t
R
RPU
P
tr = 5µs
Internal Pull-up Resistor
Output Capacitance
Detect to RESET Lowt
V
CC
Slew Rate
V
CC
(V
- V
- V
LTL
HTL
)
)
HTL
Slew Rate
V
CC
(V
LTL
VCC Detect to RESET Hight
Note: A 1kΩ resistor maybe required in some applications for proper operation of the microprocessor reset control circuit.
3.55.07.5kΩ
10pF
210µs
300µs
0ns
200350500ms
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
5 of 9
Page 6
October 2003
rev 1.0
Family Selection Guide
ASM1233M
Part #RESET Voltage (V)
ASM18104.620, 4.370, 4.120150Push-PullLOW
ASM18114.620, 4.350, 4.130150Open-DrainLOW
ASM18124.620, 4.350, 4.130150Push-PullHIGH
ASM18153.060, 2.880, 2.550150Push-PullLOW
ASM18163.060, 2.880, 2.550150Open-DrainLOW
ASM18173.060, 2.880, 2.550150Push-PullHIGH
ASM1233D4.625, 4.375, 4.125350Open-DrainLOW
ASM1233M4.625, 4.375, 2.720350Open-DrainLOW
RESET Time
(ms)
Output StageRESET Polarity
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
6 of 9
Page 7
October 2003
rev 1.0
Package Information
ASM1233M
Plastic SO-8 (8-Pin)
EH
D
A1
e
B
InchesMillimeters
MinMaxMinMax
Plastic SO-8 (8-Pin)
A0.0530.0691.351.75
A10.0040.0100.100.25
B0.0130.0200.330.51
C0.0070.0100.190.25
e0.0501.27
E0.1500.1573.804.00
H0.2280.2445.806.20
L0.0160.0500.401.27
D0.1890.1974.802.00
0° - 8°
A
TO-92 (3-Pin)
A
B
Section
A-A
D
F
C
E
L
G
H
A0.1750.1954.454.95
B0.1700.1924.324.96
C0.5000.61012.7015.49
D0.0160.0220.4060.559
E0.0950.1052.412.67
F0.0450.601.141.52
G0.450.0601.141.52
H0.0850.0952.162.41
C
I
Bottom View
InchesMillimeters
MinMaxMinMax
Plastic SO-8 (8-Pin)
M
K
TO-92* (3-Pin)
L
D
J
Section
A-A
I0.1300.1553.303.94
J0.0140.0200.350.51
K0.0930.1152.362.92
L45°60°45°60°
M0.118 Typical3.00
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
7 of 9
Page 8
October 2003
rev 1.0
Ordering Information
ASM1233M
Device Summary
RESET
Part Number
ASM1233M-554.6255350LOW
ASM1233M-54.37510350LOW
ASM1233M-32.72015350LOW
ASM1233MS-554.6255350LOW
ASM1233MS-54.37510350LOW
ASM1233MS-32.72015350LOW
* Add /S to Part Number for straight (unformed) leads. (i.e. ASM1233xx-x/S)
** Internal 5kΩ resistor pull-up
Output
Vol tage (V)
RESET
Tol era nce
(%)
RESET
Time (ms)
Open-Drain
Output
Stage**
TO-92
Package*
SO-8
Package
RESET
Polarity
Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice