MIC845

Micro-Power Comparator /

Battery Monitor

Teeny™ is a trademark of Micrel, Inc.

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

July 2005

M9999-070505

(408) 955-1690

General Description

The MIC845 is a precision micro-power voltage

comparator with an on-chip 2.55V reference voltage

source.

Intended for voltage monitoring applications, the

MIC845 can be used with an external resistor divider

to detect a wide range of voltages, or without

external resistors to directly monitor voltages with its

high input impedance CMOS input.

The MIC845 incorporates a voltage reference and

comparator with fixed internal hysteresis. When the

2.55V internal threshold is crossed, the output

switches polarity.

MIC845 is available with a push-pull or open-drain

output stage. The push-pull output stage is

configured for both active high or active low output;

the open-drain output stage is only configured active

high.

Supply current is extremely low (typically 1µA),

making it ideal for portable applications.

MIC845 is supplied in Micrel’s Teeny™ 5-lead SC-

70 package.

Data sheets and support documentation can be

found on Micrel’s web site at www.micrel.com.

Teeny™

Features

• Extremely low 1µA supply current (typical)

• 2.55V on chip reference

• ±2% voltage threshold accuracy

• Optimized for PDAs, cellular telephones, pagers,

and other battery-powered devices

• Open-drain output can be pulled up to 6V

regardless of supply voltage

• 5-lead SC-70 package

Applications

• PDAs

• Pagers

• Cordless phones

• Portable electronics

• Motherboards

• Bladed servers

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Typical Applications

R1

INP

GND

OUT

MIC845

Internal Fixed Hysteresis

R2

Threshold Detector with

3.3V

INP

GND

OUT

to Host

Memory

power

Lithium

Coin Cell

MIC845

Nano-Power Battery Monitor