New Industry Products

Linear Technology Debuts LTC4054 Battery Charger

March 09, 2003 by Jeff Shepard

Linear Technology Corp. (Milpitas, CA) introduced the LTC4054, a single-cell, linear, lithium-ion (Li-Ion) battery charger for single-cell 4.2V Li-ion and lithium-polymer batteries. With on-board charge-termination circuitry and a power transistor housed in a five-lead, 1mm high, SOT-23 (ThinSOT) package, the LTC4054 can deliver up to 800mA charge current in the tiny package without requiring an external transistor. The IC charges the battery in constant-current/constant-voltage mode and terminates charging after detecting C/10.

The LTC4054 requires no sense resistor, blocking diode or charge termination control circuit allowing a complete design to fit in just 18mm² board area with 1mm height. To eliminate the risk of overheating, the LTC4054 incorporates thermal feedback regulation by automatically controlling the charge current to limit the die temperature during high power or high ambient operation temperature. The LTC4054 keeps the battery "fresh" after charge termination by monitoring the battery's voltage and automatically recharging it if the voltage drops below a set threshold.

The float voltage is preset at 4.2V with ±0.5 percent accuracy. By measuring the voltage on the LTC4054's PROG pin, the user can monitor charge current for the purpose of gas gauging. The LTC4054 operates from a 4.25V to 6.5V input source. The LTC4054 is priced at $1.40 each in 1,000-piece quantities.