July 2004

1

M9999-072004

MIC79110

Micrel

MIC79110

Simple 1.2A Linear Li-Ion Battery Charger

General Description

The Micrel MIC79110 is a simple and accurate lithium ion

battery charger. Featuring a built-in pass transistor, precision

programmable current limiting (±5%), and precision voltage

termination (±1.5% over temperature) all in a very small

package, the MIC79110 packs full functionality into a small

space.

Other features of the MIC79110 include two independent

end-of-charge indications, including a digital indication that is

programmable with a resistor-to-ground and an analog cur-

rent output that is proportional to the output current, allowing

for monitoring of the actual charging current.

Additional

features include very low dropout (500mV over the tempera-

ture range), thermal shutdown, and reverse polarity protec-

tion. In the event the input voltage to the charger is discon-

nected, the MIC79110 also provides minimal reverse-current

and reversed-battery protection.

Available in both fixed 4.2V and adjustable outputs, the

MIC79110 is offered in the leadless 3mm x 3mm MLF-10 with

an operating junction temperature range of –40˚C to +125˚C.

Typical Application

VIN

SD

REOC

RSET

BAT

SNS

DEOC

ACHG

GND

MIC79110

4.2V

Li-Ion

Cell

10k

Ω

SHUTDOWN

ENABLE

4k

Ω

1k

Ω

167

Ω

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Features

• Input voltage range: 2.5V to 16V

• High output voltage accuracy of ±0.75% over –5°C to

+60˚C and ±1.5% over temperature

• Current Limit ±5% accurate from –5°C ≤ Tj ≤ + 125°C

• Programmable End-of-Charge Flag

• Analog output proportional to output current

• Adjustable and Fixed 4.2V Output

• Low dropout voltage of 500mV at 700mA load, over

temperature

• 1.2A output current

• Excellent line and load regulation specifications

• Reverse current and reverse battery protection

• Thermal shutdown and current limit protection

• Tiny 3mm × 3mm MLF™-10 package

• Junction Temperature Range: –40°C to +125°C

Applications

• Cellular phones

• PDAs

• Digital cameras

• Camcorders

• MP3 players

• Notebook PCs

• Portable Meters

• Cradle chargers

• Car chargers

• Battery packs

MLF and