www.fairchildsemi.com

REV. 1.5.1 7/15/02

PRELIMINARY INFORMATION describes products that are in the design stage. Specifications may change

in any manner whatever without notice. Contact Fairchild Semiconductor for current information.

Features

• Feature

• Precision Voltage Monitor for 3V, 3.3V or 5V Power

Supplies

• 6µA Supply Current

• 140ms Minimum Reset Pulse Width

• Active Low Manual Reset Input

• No External Components

• 4-Pin SOT-143 Package

Applications

• Critical Microprocessor Power Monitoring

• Portable Equipment

• Intelligent Instruments

• Computers & Printers

• Controllers

Description

The FM811/FM812 is a low cost microprocessor supervisory

circuit that asserts a reset if the power supply drops below a

designated threshold or the manual reset pin is forced low.

Several different reset thresholds are available to

accommodate systems operating at 3V, 3.3V or 5V.

The FM811 has an active low RESET output, while the

FM812 offers an active high RESET output. The reset output

is guaranteed to remain asserted for a minimum of 140ms

The FM811/FM812 is available in a 4-pin SOT-143.

Typical Applications

FM811

FM812

µP

RESET

RESET

INPUT

MR

(RESET)

( ) = FM812

FM811/812

Microprocessor Reset Circuits