ADP2291

FEATURES Simple, safe linear charger for single-cell lithium battery 4.5 V to 12 V input voltage range Adjustable charging current up to 1.5 A Low cost PNP external pass element Automatic reverse isolation with no external blocking diode Output overshoot protection Deep discharge precharge mode Thermal shutdown Automatic recharge Programmable termination timer LED charging status indicator 4.2 V output voltage with ±1% accuracy over line and temperature 1 µA shutdown supply current Small, 8-lead MSOP and 3 × 3 mm LFCSP packages APPLICATIONS Wireless handsets Smart handhelds and PDAs Digital cameras Single-cell, lithium ion-powered systems Cradle chargers Compact, 1.5 A Linear Charger for Single-Cell Li+ Battery ADP2291 GENERAL DESCRIPTION The ADP2291 is a constant-current/constant-voltage linear charger for a single-cell, lithium ion battery, requiring just a few components to provide a simple and safe charging system that operates from a wide 4.5 V to 12 V input voltage range. It features an internally controlled, multistep charging cycle that improves battery life. An external, low cost PNP provides the charging current to the battery, and an external resistor sets the maximum charge current. A small, external capacitor programs the maximum charge time. The controller includes an LED driver to indicate the battery charging status. Safety features include charging stop mode for battery faults, output overshoot protection, and thermal shutdown. The ADP2291 also features auto...