ASM161 Datasheet, PDF (1/9 Pages) Alliance Semiconductor Corporation – uP Supervisory Circuit

April 2008
rev 1.5
µP Supervisory Circuit
ASM161/ASM162
General Description
The ASM161 and ASM162 are cost effective, low power
supervisory circuits that monitor power supplies in
microprocessor, microcontroller and digital systems. If the
power supply drops below the reset threshold level, a
reset is asserted and remains asserted for atleast 800ms
after VCC has risen above the reset threshold. An
improved manual reset architecture gives the system
designer additional flexibility.
The debounced manual reset input is negative edge
triggered. The reset pulse period generated by a MR
transition is a minimum of 800 ms and a maximum of
2 sec duration. In addition, The MR input signal is
blocked for an additional 49µS minimum after the reset
pulse ends. During the MR disable period, the
microcontroller is guaranteed a time period free of
additional manual reset signals. During this period DRAM
contents can be refreshed or other critical system tasks
undertaken. Low power consumption makes the
ASM161/162 ideal for use in portable and battery
operated equipments. With 3V supplies power
consumption is 8µW typically and 30µW maximum. The
ASM161 has an open-drain, active-LOW RESET output
and requires an external pull-up resistor. The ASM162
has an active HIGH RESET output.
The ASM161/162 are offered in compact 4-pin SOT-143
packages. No external components are required to trim
threshold voltage for monitoring different supply voltages.
With six different factory set, reset, threshold ranges from
2.63V to 4.63V, the ASM161/162 are suitable for
monitoring 5V, 3.6V and 3.0V supplies. The ASM161/162
are available in temperature ranges 0°c to 70°c and -40°c
to +85°c.
Reset Threshold
Part Suffix
L
Voltage (V)
4.63
M
4.38
J
4.00
T
3.08
S
2.93
R
2.63
Key Features
• Edge triggered manual reset input
• single pulse output
• 49µS minimum MR disable period after reset
• CMOS/TTL logic or switch interface
• Debounced input
• Low supply current extends battery life
6µA / 15µA typ/max at 5.5V
4.5µA / 10µA typ/max at 3.6V
• Long reset period
• 0.8 sec minimum, 2 sec maximum
• Two reset polarity options
ASM161: Active LOW, open-drain
ASM162: Active HIGH
• Pinout matches the ASM811/812
• Small 4-Pin SOT-143 package
• Two temperature ranges: 0°c to 70°c and -40°c to +85°c
Applications
• PDAs
• Appliances
• Computers and embedded controllers
• Wireless communication systems
• Battery operated and intelligent instruments
• Automotive systems
• Safety systems
PulseCore Semiconductor Corporation
1715 S. Bascom Ave Suite 200 Campbell, CA 95008 • Tel: [phone] • Fax: [phone]
www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.