April 2008

ASM161/ASM162

rev 1.5

Notice: The information in this document is subject to change without notice.

PulseCore Semiconductor Corporation

1715 S. Bascom Ave Suite 200 Campbell, CA 95008

• Tel: 408-879-9077 • Fax: 408-879-9018

www.pulsecoresemi.com

µP Supervisory Circuit

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

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

Voltage (V)

L

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