October 2003
rev 1.0
ASM811, ASM812
4 Pin µP Voltage Supervisor with Manual Reset
Six voltage thresholds are available to support 3V to 5V
systems:
General Description
The ASM811/ASM812 are cost effective low power supervisors
designed to monitor voltage levels of 3.0V, 3.3V and 5.0V
power
supplies
in
low-power
microprocessor
(µP),
microcontroller (µC) and digital systems. They provide excellent
reliability by eliminating external components and adjustments.
A reset signal is issued if the power supply voltage drops below
a preset reset threshold and is asserted for at least 140ms after
the supply has risen above the reset threshold. The ASM811
has an active-low output RESET that is guaranteed to be in the
correct state for V
CC
down to 1.1V. The ASM812 has an active-
high RESET output. The reset comparator is designed to ignore
fast transients on V
CC
. A debounced manual reset input allows
the user to manually reset the systems to bring them out of
locked state.
Low power consumption makes the ASM811/ASM812 ideal for
use in portable and battery operated equipment. The ASM811/
ASM812 are available in a compact 4-pin SOT-143 package
and thus use minimal board space.
RESET THRESHOLD
Suffix
L
M
J
T
S
R
Voltage
4.63
4.38
4.00
3.08
2.93
2.63
Features
•
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New 4.0V threshold option
9µA supply current
Monitor 5V, 3.3V and 3V supplies
Manual reset input
140ms min. reset pulse width
Guaranteed over temperature
Active-low reset valid with 1.1V supply (ASM811)
Small 4-pin SOT-143 package
No external components
Power-supply transient-immune design
Applications
•
•
•
•
•
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Computers and Controllers
Embedded controllers
Portable/Battery operated systems
Intelligent instruments
Wireless communication systems
PDAs and handheld equipment
Automotive systems
Safety Systems
Typical Operating Circuit
V
CC
V
CC
V
CC
µP
MR RESET
(RESET)
GND
RESET (RESET)
Input
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