The LTC4054-4.2/LTC4054X-4.2 is a standalone linear Li-Ion battery charger with thermal regulation in ThinSOT from Linear Technology Corporation. It features programmable charge current up to 800mA, no external MOSFET, sense resistor or blocking diode required, and a complete linear charger in ThinSOT package for single cell lithium-ion batteries.
The LTC4054 family provides a compact, ThinSOT‑23 packaged Li‑ion charger that operates from a 4.25‑6.5 V input and delivers up to 800 mA of charge current. It features internal MOSFET power switching, thermal regulation, and a fixed 4.2 V float voltage with ±1 % accuracy, eliminating the need for external sense resistors or blocking diodes.
Operation follows a constant‑current/constant‑voltage algorithm with C/10 termination, UVLO protection, and optional trickle‑charge mode (LTC4054 only). The device includes status pins for charge monitoring, shutdown control, and a programmable current‑monitor output. Thermal feedback reduces current when junction temperature approaches 120 °C, and shutdown current is as low as 25 µA.
| Input Supply Voltage (Vec) | 4.25 V – 6.5 V |
|---|---|
| Maximum Charge Current | 800 mA |
| Float Voltage | 4.2 V ±1 % |
| Shutdown Supply Current | 25 µA |
| Trickle‑Charge Threshold (LTC4054 only) | 2.9 V |
The LTC4054 can deliver up to 800 mA of charge current.
In shutdown mode the device draws only about 25 µA.
The UVLO threshold is set at approximately 2.9 V.