September 2003
rev 1.0
ASM1233D
Low Power, 5µP Reset, Active LOW, Open-Drain Output
Applications
•
•
•
•
•
•
•
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
General Description
The ASM1233D is a voltage supervisory device with low-power,
5V µP Reset, and an active LOW, open-drain output. Maximum
supply current over temperature is a low 20µA.
The ASM1233D generates an active LOW reset signal
whenever the monitored supply is out of tolerance. A precision
reference and comparator circuit monitor power supply (V
CC
)
level. Tolerance level options are 5%, 10% and 15%. When an
out-of-tolerance condition is detected, an internal power-fail
signal is generated which forces an active LOW reset signal.
After V
CC
returns to an in-tolerance condition, the reset signal
remains active for 350ms to allow the power supply and system
microprocessor to stabilize.
The ASM1233D is designed with a open-drain output stage and
operates over the extended industrial temperature range.
Devices are available in compact surface mount SOT-223
packages and 3-lead TO-92 packages.
Other low power products in this family include the ASM1810/
11/12/15/16/17 and ASM1233M.
Typical Operating Circuit
V
CC
ASM1233D
Microprocessor
RESET
RESET
GND
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
CC
returns to an in-tolerance con-
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 SOT-223 package
Operating temperature -40°C to +85°C
1
GND
Reference
Supply
Tolerance
Bias
Block Diagram
V
CC
3
ASM1233D
5.0kΩ
2
RESET
+
-
Delay
150ms
Typical
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
September 2003
rev 1.0
ASM1233D
Pin Configuration
SOT-223
ASM1233D-X
TO-92*
ASM1233D-X
RESET
GND
V
CC
2
4
3
1
GND
1
2
3
Pin Description
Pin #
Pin Name
SOT-223
1
2
3
4
* See Ordering Information
Description
Ground
Active LOW reset output
Power supply input
Ground (SOT-223 only)
TO-92
1
2
3
-
GND
RESET
V
CC
GND
Low Power, 5µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
2 of 8
September 2003
rev 1.0
ASM1233D
V
CC
V
CCTP
(MAX)
V
CCTP
V
CCTP
(MIN)
t
F
Application Information
Operation - Power Monitor
The ASM1233D 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
threshold. When an out-of-tolerance V
CC
voltage is detected,
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
R
V
CCTP
(MAX)
V
CCTP
(MIN)
V
CCTP
RESET
t
RPD
V
OL
Figure 2: Timing Diagram: Power-Down
V
CC
t
RPU
V
OH
RESET
Figure 1: Timing Diagram: Power-Up
~
~
3 of 8
the monitored power supply voltage is below the reset
~
~
~
~
Low Power, 5µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
September 2003
rev 1.0
ASM1233D
Absolute Maximum Ratings
Parameter
Voltage on V
CC
Voltage on RESET
Operating Temperature Range
Soldering Temperature (for 10 sec)
Storage Temperature
-55
Min
-0.5
-0.5
-40
Max
7
V
CC
+ 0.5
85
260
125
Unit
V
V
°C
°C
°C
NOTE: These are stress ratings only and functional use is not implied. Exposure to absolute maximum ratings for pro-
longed periods of time may affect device reliability.
Unless otherwise noted, V
CC
= 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
Electrical Characteristics
Parameter
Supply Voltage
Output Voltage
Output Current
Operating Current
Operating Current
V
CC
Trip Point (ASM1233D-5)
V
CC
Trip Point (ASM1233D-10)
V
CC
Trip Point (ASM1233D-15)
Internal Pull-up Resistor
Output Capacitance
RESET Active Time
V
CC
Detect to RESET Low
V
CC
Slew Rate
(V
CCTP
(MAX) to V
CCTP
(MIN)
V
CC
Slew Rate
(V
CCTP
(MIN) to V
CCTP
(MAX)
V
CC
Detect to RESET High
Symbol
V
CC
V
OH
I
OL
I
CC
I
CC
V
CCTP
V
CCTP
V
CCTP
R
P
C
OUT
t
RESET
t
RPD
t
F
t
R
t
RPU
Conditions
Min
1.2
Typ
Max
5.5
Unit
V
V
mA
I
OUT
< 500 µA
Output = 0.4V, V
CC
>= 2.7V
V
CC
< 5.5V, RESET output open
V
CC
< =3.6V, RESET output
open
V
CC
- 0.5V
+8
V
CC
- 0.1V
8
6
4.50
4.25
4.00
3.5
4.625
4.375
4.125
5.0
20
15
4.74
4.49
4.24
7.5
10
µA
µA
V
V
V
kΩ
pF
ms
µs
µs
250
350
2
450
5
300
0
t
r
= 5µs
250
350
450
ns
ms
Note: The t
F
value is for reference in defining values for t
RPD
and should not be considered for proper operation or use.
Low Power, 5µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
4 of 8
September 2003
rev 1.0
ASM1233D
Family Selection Guide
Part #
ASM1810
ASM1811
ASM1812
ASM1815
ASM1816
ASM1817
ASM1233D
ASM1233M
RESET Voltage (V)
4.620, 4.370, 4.120
4.620, 4.350, 4.130
4.620, 4.350, 4.130
3.060, 2.880, 2.550
3.060, 2.880, 2.550
3.060, 2.880, 2.550
4.625, 4.375, 4.125
4.625, 4.375, 2.720
RESET Time
(ms)
150
150
150
150
150
150
350
350
Output Stage
Push-Pull
Open-Drain
Push-Pull
Push-Pull
Open-Drain
Push-Pull
Open-Drain
Open-Drain
RESET Polarity
LOW
LOW
HIGH
LOW
LOW
HIGH
LOW
LOW
Low Power, 5µP Reset, Active LOW, Open-Drain Output
Notice: The information in this document is subject to change without notice
5 of 8
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