2-cell Li-Ion charger in 8-TSSOP
The BQ2057TTS is a Texas Instruments linear charger IC designed specifically for 2-series Lithium Ion or Lithium Polymer battery packs, terminating at 8.2V. The charge current is set by an external resistor — constant-current programmable — so you size the resistor for your pack capacity and thermal budget. The 8-TSSOP package keeps the footprint small, but the linear topology means the pass element dissipates the voltage drop times charge current as heat; a 500 mA charge from a 12V supply drops roughly 3.8V across the internal FET, so the thermal pad on the PCB layout matters for sustained charging.
Temperature range and sourcing posture
Mounting and footprint
Surface Mount in the 8-TSSOP package (0.173", 4.40mm width). The supply voltage maximum is 15V, so the input rail can be a 12V wall adapter or a 5V USB port — but the linear dropout means the input must stay above the battery voltage plus the dropout of the internal pass element.