HE4057A

A high-performance single-cell lithium-ion battery CC/CV linear charger. The SOT23-6 package combined with minimal external components makes it ideal for portable products, suitable for both USB power supplies and adapter power supplies. Based on a special internal MOSFET architecture with reverse-charge protection circuitry, no external sense resistors or isolation diodes are required. Thermal feedback can regulate the charging current to reduce chip temperature when the ambient temperature is too high or in high-power applications. The charge voltage is fixed at 4.2V, while the charge current can be externally set via a single resistor. When the charge current drops to 1/10 of the programmed value after reaching the final float voltage, the chip terminates the charge cycle. When the input voltage is disconnected, the device enters sleep mode and battery leakage current drops below 1uA. The device can be placed in shutdown mode, reducing quiescent current to 25uA. Additional features include undervoltage lockout, automatic recharge, and two status pins to indicate charging and charge termination.

Applications

• Charger

Key features

• Single-cell Li-Ion battery charging up to 500mA with adaptive charge current
• 25uA quiescent current in standby mode
• No external MOSFET, sense resistors, or isolation diodes required
• 2.9V trickle charging
• Constant current/constant voltage operation with thermal regulation for maximizing charge rate without risk of overheating under C/10 charge termination
• Soft-start to limit inrush current
• Automatic recharge
• Reverse battery protection
• Dual-output charge status indication with battery absent and fault status display
• Battery undervoltage protection to activate charging
• 4.2V pre-charge voltage with ±1% accuracy
• Operating temperature range -40°C to 105°C
• Charge current monitor output for battery fuel gauging
• SOT23-6L package