MIC79050 Linear Li-Ion Battery Charger0 pages

August 2005 1 MIC79050
MIC79050 Micrel, Inc.
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
General Description
The MIC79050 is a simple single-cell lithium-ion battery charger.
It includes an on-chip pass transistor for high precision
charging. Featuring ultrahigh precision (+0.75% over the Liion
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 temperature 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
• 10ìA 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 SOIC-8, and SOT-223
• Pulse charging capability
Applications
• Li-ion battery charger
• Celluar phones
• Palmtop computers
• PDAs
• Self charging battery packs
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
Voltage
Junction
Temp. Range
Standard Pb-Free Package
MIC79050-4.2BS MIC79050-4.2YS 4.2V –40ºC to +125ºC SOT-223-3
MIC79050-4.2BM MIC79050-4.2YM 4.2V –40ºC to +125ºC SOIC-8
MIC79050-4.2BMM MIC79050-4.2YMM 4.2V –40ºC to +125ºC MSOP-8