2.5V to 6.5V supply — the portable-equipment power rail
The TPS658310YFFR from Texas Instruments is a power management IC designed for portable equipment, accepting a supply range of 2.5V to 6.5V. That span covers single-cell Li-ion (3.0V–4.2V nominal) and two-cell alkaline or NiMH stacks, so the same BOM position works across product variants without a regulator swap.
49-DSBGA (2.8x2.8 mm) — footprint and assembly constraints
The 49-DSBGA package measures 2.8x2.8 mm with a 0.4 mm ball pitch. That pitch forces a minimum 4-layer PCB for fan-out — two-layer boards cannot route the inner balls without buried vias. Moisture sensitivity level (MSL) is not stated in this listing; confirm the bake requirement before opening the reel.