The TPS61256CYFFT is a fixed 5V output boost converter from Texas Instruments, designed to step up a 2.5V to 4.85V input rail — exactly the range of a single Li-ion or Li-Po cell (3.0V to 4.2V nominal) — to a regulated 5V bus.
2.4A switch — what you can actually draw
The integrated switch is rated for 2.4A peak current. At 5V output from a 3.3V input, that translates to roughly 1.2A to 1.4A continuous output before the current limit folds back — enough for a Raspberry Pi Zero or a string of addressable LEDs. The 3.5MHz switching frequency keeps the inductor small (1 µH to 2.2 µH range) and the output capacitor in the 10 µF class, so the total power stage fits in a thumbnail.
DSBGA-9: tiny footprint, no lab bench required
Housed in a 9-bump DSBGA (0.4 mm pitch), this part is about 1.2 mm × 1.2 mm — smaller than a grain of rice. The synchronous rectifier means no external Schottky diode, saving one more component. For a field-service swap: the bumps are underneath and the part is laser-marked on top, but orientation is unambiguous if you have the datasheet pad map. Reflow with a hot-air station at 260°C peak; no ESD lab needed if you handle it by the edges.