© Semiconductor Components Industries, LLC, 2011

August, 2011 − Rev. 3

1

Publication Order Number:

ASM161/D

ASM161, ASM162

mP Supervisory Circuit

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 at

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 49

mS 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 3 V

supplies, power consumption is 8

mW typically and 30 mW 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 2.63 V to 4.63 V, the ASM161/162 are

suitable for monitoring 5 V, 3.6 V and 3.0 V supplies. The

ASM161/162 are available in temperature ranges 0

°C to 70°C and

−40

°C to +85°C.

Features

6

mA / 15 mA typ/max at 5.5 V

4.5

mA / 10 mA typ/max at 3.6 V

ASM161: Active LOW, Open−drain

ASM162: Active HIGH

and −40

°C to +85°C

Applications

http://onsemi.com

PIN CONFIGURATIONS

See detailed ordering and shipping information in the package

dimensions section on page 6 of this data sheet.

ORDERING INFORMATION

4.63

L

4.38

M

4.00

J

3.08

T

2.93

S

Voltage (V)

RESET THRESHOLD

SOT−143

4 LEAD

CASE 527AF

ASM161

(Top View)

Part Suffix

RESET

RESET

GND

GND

MR

MR

ASM162

(Top View)

RESET is open drain

2.63

R

11