ASM1811

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

rev 1.4

Low Power 5V µP Reset Active LOW, Open - Drain Output

February 2005

General Description

The ASM1811 is a voltage supervisory device with a low-power,

5V µP Reset, active LOW, open-drain output. Maximum supply

current over temperature is a low 20µA.

The ASM1811 generates an active LOW reset signal whenever

the monitored supply is out of tolerance. A precision reference

Tolerance level options are 5%, 10% and 15%. When an out-of-

tolerance condition is detected, an internal power-fail signal is

returns to an in-tolerance condition, the reset signal remains

active for 150ms to allow the power supply and system

microprocessor to stabilize.

The ASM1811 is designed with a open-drain output stage and

operates over the extended industrial temperature range.

Devices are available in low cost TO-92 and compact surface

mount SOT-23 packages.

Other low power products in this family include the ASM1810/

12/15/16/17, ASM1233D and ASM1233M.

Key Features

•

Low Supply Current

•20 µA maximum (5.5 V)

•

Automatically restarts a microprocessor after power failure

•

dition

•

Active LOW power-up reset

•

Precision temperature-compensated voltage reference and

comparator

•

Eliminates external components

•

Low cost TO-92 and compact surface mount SOT-23 pack-

ages

•

Operating temperature -40°C to +85°C

Applications

•

Set-top boxes

•

Cellular phones

•PDAs

•

Energy management systems

•

Embedded control systems

•

Printers

•

Single board computers

Typical Operating Circuit

Block Diagram

Microprocessor

RESET

RESET

GND

ASM1811

Supply

Reference

Delay

150ms

Typical

Tolerance

Bias

+

-

2

ASM1811

Supply

Delay

150ms

Typical

Tolerance

Bias

-

GND

RESET

Reference

+

1

3