Overview

TF4057 is a constant current/constant voltage linear charger for single-cell lithium-ion battery with excellent performance. TF4057 adopts SOT23-6 package with less peripheral components, making it very suitable for portable products, and suitable for supplying USB power and adapter power.
Based on the special internal MOSFET structure and anti-reverse charging circuit, the TF4057 does not require external sense resistors and isolation diodes. When the external ambient temperature is too high or in high-power applications, thermal feedback can adjust the charging current to reduce the chip temperature. The charge voltage is fixed at 4.2V, while the charge current can be set externally with a resistor. When the charge current drops to 1/10 of the set value after reaching the final float voltage, the chip will terminate the charge cycle
When the input voltage is disconnected, the TF4057 enters sleep state and the battery leakage current will drop below 1uA. TF4057 can be set in shutdown mode, at this time the chip quiescent current is reduced to 25uA
The TF4057 also includes other features: battery temperature monitoring, undervoltage lockout, automatic recharge and two status pins to indicate charge and charge termination

characteristic

◆Programmable charging current 500mA
◆No need for external MOSFETs, sense resistors and blocking diodes
◆Complete Linear Charger in SOT23-6 Package for Single Cell Lithium Batteries
◆Constant current/constant voltage operation with thermal regulation to maximize charge rate without risk of overheating
◆4.2V Precharge Voltage Accurate to ±1
◆Charge current monitor output for battery charge detection
◆automatic recharge
◆Charge status dual output, no battery and fault status display
◆C/10 charge termination
◆Quiescent current in standby mode is 25uA
◆2.9V trickle charge
◆Soft Start Limits Inrush Current

Scope of application

◆Mobile phones, PDA
◆MP3, MP4 player
◆charger
◆digital camera
◆E-dictionary
◆Bluetooth, GPS navigator
◆portable device