LinearTechnologyCorporationintroducestheLTC4054

Linear Technology Corporation introduces the LTC4054, a single-cell linear Li-Ion battery charger with on-board charge termination circuitry and power transistor housed in a 5-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. Alternative solutions with an integrated transistor are housed in a package twice the size of the LTC4054. Moreover, other linear charger controllers in a SOT-23 package depend on an external transistor to deliver the same amount of current as the LTC4054. In addition to an integrated transistor, 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 operation or high ambient temperature. The LTC4054 keeps the battery 揻resh?after charge termination by monitoring the battery抯 voltage and automatically recharging it if the voltage drops below a set threshold. Because of its standalone operation, compact solution and low 4.25V input supply operation, the LTC4054 is an ideal solution for charging a Li-Ion battery from the USB port in handhelds as well as Bluetooth?headsets, portable MP3 players, battery powered GPS devices, PDAs and cell phones.

The LTC4054 is a linear charger for single-cell 4.2V Li-ion and Li-Polymer batteries. The IC charges the battery in constant-current/constant-voltage mode and terminates charging after detecting C/10. The termination event is indicated by a Charge Status pin, which can signal a microcontroller or drive an LED. The user sets the charge current with a resistor. The float voltage is preset at 4.2V with ±0.5% accuracy. By measuring the voltage on the LTC4054抯 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.

Summary of Features: LTC4054
Programmable Charge Current up to 800mA
No External MOSFET, Sense Resistor Blocking Diode Required
Complete Linear Charger in ThinSOT Package for 4.2V Single-Cell Li-Ion and Li-Polymer Batteries
Thermal Regulation to Maximize Charge Rate without Risk of Overheating
USB Compatible Charger
Automatic Charge Termination
Automatic Recharge