MIC79050 Linear Li-Ion Battery Charger - Micrel - #1

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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