LR LR4054A-T

LR4054A is a complete constant-current/constant-voltage linear charger IC for single-cell lithium-ion batteries. The SOT package and minimal external component count make the LR4054A ideally suited for portable applications. The LR4054A is specifically designed to operate within USB power specifications. The internal MOSFET architecture eliminates the need for external sense resistors and isolation diodes. Thermal feedback regulates the charge current to limit die temperature during high-power operation or elevated ambient temperature conditions. The charge voltage is fixed at 4.2V, while the charge current is externally programmable via a single resistor. When the charge current drops to 1/10 of the programmed value after the final float voltage is reached, the LR4054A automatically terminates the charge cycle. When the input voltage (AC adapter or USB supply) is removed, the LR4054A automatically enters a low-current state, reducing battery leakage current to below 2uA. The LR4054A can be placed in shutdown mode, reducing supply current to 25uA. Additional features include a charge current monitor, undervoltage lockout, automatic recharge, and a status pin for indicating charge termination and input voltage presence.

• Programmable charge current up to 500mA
• No MOSFET, sense resistor, or blocking diode required
• Reverse battery protection on output
• Complete linear charger IC for single-cell Li-Ion in SOT package with constant-current/constant-voltage operation and thermal regulation for maximizing charge rate without risk of overheating
• Direct Li-Ion battery charging from USB port
• 4.2V preset charge voltage with 1% accuracy
• Charge current monitor output for battery fuel gauging
• Automatic recharge
• Charge status output pin
• C/10 charge termination
• 25uA supply current in shutdown mode
• 2.9V trickle charge threshold
• Soft-start limits inrush current

• Cellular phones, PDAs, MP3 players
• Charging docks
• Bluetooth device portable lithium battery chargers