June 2000

1

MIC79050

MIC79050

Micrel

Typical Applications

Li-Ion

Cell

4.2V

±0.75% Over Temp

IN

BAT

GND

MIC79050-4.2BS

Regulated or

unregulated

wall adapter

Simplest Battery Charging Solution

4.2V

±0.75%

Li-Ion

Cell

IN

BAT

FB

GND

EN

MIC79050-4.2BMM

External PWM*

*See Applications Information

Regulated or

unregulated

wall adapter

Pulse-Charging Application

MIC79050

Simple Lithium-Ion Battery Charger

Preliminary Information

General Description

The MIC79050 is a simple single-cell lithium-ion battery

charger. It includes an on-chip pass transistor for high preci-

sion charging. Featuring ultrahigh precision (+0.75% over the

Li-ion battery charging temperature range) and “zero” off

mode current, the MIC79050 provides a very simple, cost

effective solution for charging lithium-ion battery.

Other features of the MIC79050 include current limit and

thermal shutdown protection. In the event the input voltage to

the charger is disconnected, the MIC79050 also provides

minimal reverse-current and reversed-battery protection.

The MIC79050 is a fixed 4.2V device and comes in the

thermally-enhanced MSO-8, SO-8, and SOT-223 packages.

The 8-pin versions also come equipped with enable and

feedback inputs. All versions are specified over the tempera-

ture range of –40

°C to +125°C.

Features

• High accuracy charge voltage:

±0.75% over -5°C to + 60°C (Li-ion charging

temperature range)

• “Zero” off-mode current

•10

µA reverse leakage

• Ultralow 380mV dropout at 500mA

• Wide input voltage range

• Logic controlled enable input (8-pin devices only)

• Thermal shutdown and current limit protection

• Power MSOP-8, Power SOP-8, and SOT-223

• Pulse charging capability

Applications

• Li-ion battery charger

• Celluar phones

• Palmtop computers

• PDAs

• Self charging battery packs

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

Ordering Information

Part Number

Voltage

Junct. Temp. Range

Package

MIC79050-4.2BS

4.2V

–40

°C to +125°C

SOT-223

MIC79050-4.2BM

4.2V

–40

°C to +125°C

SOP-8

MIC79050-4.2BMM

4.2V

–40

°C to +125°C

MSOP-8