Single-cell charger with I²C and USB control
The Texas Instruments BQ24257RGER is a single-cell, multi-chemistry battery charger that accepts input from a USB port or a DC adapter, with the charge current programmable up to 2 A via the I²C interface. The device integrates fault protection against over-temperature and over-voltage conditions, and includes a programmable timer for charge termination.
2 A charge current and 4.44 V battery regulation
The maximum charge current of 2 A sets the charge-time floor for a single-cell Li-ion or Li-poly pack; the battery regulation voltage tops out at 4.44 V, which covers the standard 4.2 V and 4.35 V cell chemistries with margin. The I²C interface allows the host microcontroller to adjust the charge current, set the timer, and read status registers — useful for dynamic thermal management or input current limiting when powered from a USB host.
NRND — plan for a replacement
This means TI will continue to support existing designs but advises against using this part in new projects. For new designs, evaluate the BQ24259 or BQ24261 series as pin-compatible alternatives within the same charger family — confirm the exact package and feature set against the BOM requirements.
24-VQFN package and supply range
The supply input accepts up to 6.5 V, covering standard 5 V USB and 5 V wall adapters.