WILLSEMI WS4508E-5/TR

The WS4508E is a complete constant-current / constant voltage linear charger for single cell Lithium-Ion batteries. No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The WS4508E automatically terminates the charge cycle when the charge current drops to 1/10 the programmed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the WS4508E automatically enters a low current state, dropping the battery drain current to less than 0.5uA. The WS4508E can be put into shutdown mode, reducing supply current to 45uA (Typ.). The WS4508E is available in a small package with SOT-23-5L. Standard product is Pb-Free.

• Programmable Charge Current Up to 600mA
• Over-Temperature Protection
• Under Voltage Lockout Protection
• Automatic Recharge Threshold 4.05V(Typ.)
• Charge Status Output Pin
• 2.9V Trickle Charge Threshold
• Soft-Start Limits Inrush Current

• Wireless phone
• MP3/MP4 Player
• Bluetooth device