Milpitas, Calif.—Linear Technology's LTC4075 and LTC4075X are stand alone dual-input linear battery charger ICs that automically select the charging source—either a wall adapter or a USB port—for single-cell lithium-ion batteries. Using a constant-current/constant-voltage algorithm, the chargers, for application in PDAs, MP3 players, portable test equipment, and cell phones, can deliver up to 950 mA from a wall adapter or 500 mA from a USB supply. Float voltage accuracy is ±0.6 percent. The LTC4075X disables the trickle charge function, benefiting systems requiring more charge current during low battery conditions.
The LTC4075/X is equipped with a patented thermal regulation scheme, which maximizes the charging rate without the risk of overheating. Wall-adapter charge current, USB charge current, and charge termination current is programmable via a single resistor.
The device also features under-voltage lockout, automatic recharge, a charge status indicator, and "power present" status outputs to indicate the presence of wall adapter or USB power. The LTC4075 draws less than 6 microamps from the battery terminal in standby and less than 2 microamps in shutdown mode. A data sheet is available at www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1037,C1078,C1088,P10994
The LTC4075/X is offered in a low-profile (0.75 mm) 10-lead 3-by-3 mm DFN package. The total solution footprint is less than 25 mm2 (no external MOSFET, sense resistor or blocking diode are required). The LTC4075/X is rated for operation over -40 to +85°C. Pricing begins at $1.88 each in 1k quantities.
Linear Technology, 1-800-4-LINEAR, www.linear.com