January 2006

1

MIC705/06/07/08

MIC705/06/07/08

Micrel, Inc.

MIC705/706/707/708

µP Supervisory Circuit

General Description

The MIC705, MIC706, MIC707, and MIC708 are inexpensive

mircoprocessor supervisory circuit that monitors power sup-

plies in microprocessor based systems. The circuit functions

include a watchdog timer, microprocessor reset, backup

battery switchover, power failure warning and a debounced

manual reset input.

The MIC705 and MIC706 offer a watchdog timer function

while the MIC707 and MIC708 have an active high reset

output in addition to the active low reset output.

Supplyvoltagemonitorlevelsof4.65Vand4.4Vareavailable.

TheMIC705andMIC707haveanominalresetthresholdlevel

of 4.65V while the MIC706 and MIC708 have a 4.4V nominal

threshold level. When the supply voltage drops below the

respective reset threshold level, /RESET is asserted.

Typical Application

VCC

RESET

µP

RESET

VCC

MIC705

MIC706

+5V (Regulated)

MR

WDI

I/O Line

PFO

Interrupt

PFI

DC Voltage

(Unregulated)

Manual

Reset

WDO

NMI

Features

• Debounced manual reset input is TTL/CMOS

Compatible

• Watchdog timer, 1.6s (MIC705/706)

• 4.65V or 4.40V Precision Voltage Monitor

• Early power fail warning or low battery detect

Applications

• Automotive systems

• Intelligent systems

• Critical microprocessor power monitoring

• Battery powered computers

• Computers

• Controllers

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Ordering Information

Part Number

Temperature Range

Package

Standard

Pb-Free

MIC70_N

MIC70_NY

–40ºC to +85ºC

8-Pin PDIP

MIC70_M

MIC70_MY

–40ºC to +85ºC

8-Pin SOIC