The ISL6253 is a highly integrated battery charger controller for Li-Ion/Li-Polymer batteries. High Efficiency is achieved by a synchronous buck topology and the use of a MOSFET, instead of a diode, for selecting power from the adapter or battery. The low side MOSFET emulates a diode at light loads to improve the light load efficiency and prevent system bus boosting.
ISL6253 has a feature of automatic power source selection by switching to the battery when the AC adapter is removed or switching to the AC adapter when the AC adapter is available. It also supports aircraft power applications while powering the system and not charging the battery.

Features
• ±0.5% Voltage Accuracy
• ±3% Input Current Limit Accuracy
• ±4% Accurate Battery Charge Current Limit
• Programmable Charge Limit Current, Adaptor Current
   Limit and Charge Voltage
• Fixed 300kHz PWM Synchronous Buck Controller with
   Diode Emulation at Light Load
• Output for Current Drawn from the AC Adapter
• AC Adapter Present Indicator
• Fast Input Current Limit Response
• Input Voltage Range 7V to 25V
• Up to 17.6V Battery-Voltage Set Point
• Trickle Charge Mode When Battery Voltage is below
   3.0V/Cell
• Supports 2, 3 and 4 Cell Battery Packs
• Control Adapter Power Source Select MOSFET
• Thermal Shutdown
• Aircraft Power Capable
• DC Adapter Present Indicator
• Battery Discharge MOSFET Control
• Less than 10µA Battery Leakage Current
• QFN Package
   - Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat
      No Leads - Package Outline
   - Near Chip Scale Package footprint, which improves
      PCB efficiency and has a thinner profile
• Pb-free Available

Applications
• Notebook, Desknote and Sub-notebook Computers
• Personal Digital Assistants