October 2003
rev 1.0
ASM1811
Low Power 5V µP Reset Active LOW, Open - Drain Output
Applications
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Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
General Description
The ASM1811 is a voltage supervisory device with a low-power,
5V µP Reset, active LOW, open-drain output. Maximum supply
current over temperature is a low 20µA.
The ASM1811 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 150ms to allow the power supply and system
microprocessor to stabilize.
Typical Operating Circuit
V
CC
ASM1811
The ASM1811 is designed with a open-drain output stage and
operates over the extended industrial temperature range.
Devices are available in compact surface mount SOT-23
packages and 3-lead TO-92 packages.
Other low power products in this family include the ASM1810/
12/15/16/17, ASM1233D and ASM1233M.
RESET
Microprocessor
RESET
GND
Key Features
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Low Supply Current
•20 µA maximum (5.5 V)
Automatically restarts a microprocessor after power failure
150ms reset delay after V
CC
returns to an in-tolerance con-
dition
Active LOW power-up reset
Precision temperature-compensated voltage reference and
comparator
Eliminates external components
Low-cost TO-92 package
Compact surface mount SOT-23 package
Operating temperature -40°C to +85°C
Block Diagram
V
CC
2
Supply
Tolerance
Bias
ASM1811
5.0K
Ω
1
RESET
+
-
Reference
Delay
150ms
Typical
3
GND
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
PULSECORE [ PulseCore Semiconductor ]
