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Datasheet
TP4057-42 Linear Li-Ion Battery Charger IC for Single Cell Applications (SOT-23-6 Package)
The TP4057-42 is a complete single-cell lithium-ion battery charging IC designed for compact, cost-effective portable electronics. Based on a linear CC/CV (constant current / constant voltage) charging architecture, this device provides stable and accurate charging with a preset 4.2 V float voltage and up to 500 mA programmable charge current. Its internal PMOS structure eliminates the need for external MOSFETs, sense resistors, or blocking diodes, simplifying circuit design and reducing BOM cost.
Optimised for USB and adapter-based power sources, the TP4057-42 integrates thermal regulation, battery reverse-polarity protection, automatic recharge, and C/10 charge termination. Housed in a compact SOT-23-6 package, it is well suited for space-constrained designs such as Bluetooth devices, wearables, power banks, and handheld consumer electronics where reliability and charging safety are critical.
Key Features
- Single-Cell Li-Ion Charger – Designed for one lithium-ion or lithium-polymer battery
- Accurate Charge Voltage – Fixed 4.2 V float voltage with +-1% accuracy
- Programmable Charge Current – Up to 500 mA set via a single external resistor
- Integrated Power MOSFET – No external MOSFET, sense resistor, or diode required
- Thermal Regulation – Automatically reduces charge current to prevent overheating
- Battery Reverse Protection – Protects the IC during battery polarity reversal
- Charge Status Outputs – CHRG and STDBY open-drain pins for LED or MCU indication
- Automatic Recharge – Restarts charging when battery voltage drops below threshold
- Low Standby Current – Typical 40 uA in standby mode
- Compact Package – SOT-23-6 (SOT26) suitable for dense PCB layouts
- RoHS Compliant – Pb-free and suitable for eco-compliant designs
Applications
- USB-powered lithium battery chargers
- Bluetooth accessories and IoT devices
- Power banks and portable battery packs
- MP3 players, wearables, and handheld electronics
- Embedded systems with single-cell Li-ion batteries
