2-cell Li-ion/Polymer charger with programmable current
The Texas Instruments BQ2057TTSTRG4 is a linear battery charger IC designed for 2-cell Lithium Ion or Lithium Polymer packs, delivering a regulated charge voltage of 8.2V. The charge current is constant and programmable via an external resistor, giving the BOM engineer control over the charge rate to match the cell capacity and thermal budget.
8.2V charge voltage — confirming the cell count
The 8.2V battery pack voltage is the key fit parameter: it confirms this part is intended for a 2-series Li-ion configuration (2S), not a single cell (4.2V) or a 3-series pack (12.6V). The maximum supply input is 15V, which gives headroom for a typical 12V wall adapter or USB-C PD source.
8-TSSOP footprint and assembly
Housed in an 8-TSSOP package with a 4.40mm body width and 0.65mm pin pitch, the BQ2057TTSTRG4 is a surface-mount device. The 8-TSSOP supplier device package matches the standard TSSOP-8 land pattern. No exposed thermal pad — the power dissipation is handled through the package body and PCB copper.