ASM809, ASM810

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

October 2003

rev 1.0

3 Pin Microcontroller Power Supply Supervisor

General Description

The ASM809/ASM810 are cost effective 3.0V, 3.3V and 5.0V

power supply supervisor circuits optimized for low-power

microprocessor (µP), microcontroller (µC) and digital systems.

They provide a reset output during power-up, power-down and

brown-out conditions. They provide excellent reliability by

eliminating external components and adjustments. The

ASM809/810 are improved drop-in replacements for the Maxim

MAX809/810 and feature 60% lower supply current.

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 ASM809

has an active-low RESET output that is guaranteed to be in the

active-high RESET output. The reset comparator is designed to

Low supply current makes the ASM809/ASM810 ideal for use

in

portable

and

battery

operated

equipment.

The

ASM809/ASM810 are available in a compact, industry standard

3-pin SOT23 package.

Six voltage thresholds are available to support 3V to 5V

systems:

Features:

•

Monitor 5V, 3.3V and 3V supplies

•

140ms min. reset pulse width

•

Active-low reset valid with 1.1V supply (ASM809)

•

Small 3-pin SOT-23 package

•

No external components

•

Specified over full temperature range - -40°C to 105°C

RESET THRESHOLD

Suffix

Voltage

L4.63

M4.38

J4.00

T3.08

S2.93

R2.63

Applications

•

Embedded controllers

•

Portable/Battery operated systems

•

Intelligent instruments

•

Wireless communication systems

•

PDAs and handheld equipment

•

Computers

Typical Operating Circuit

µP

RESET

Input

RESET

(RESET)

GND

GND

(RESET)