Boost converter with fixed 5V rail
The TPS61256AYFFT is a step-up (boost) DC-DC converter from Texas Instruments that delivers a fixed 5V output from a 2.5V to 4.85V input rail.
3.5 MHz switching shrinks the inductor
Switching at 3.5 MHz, the converter lets the designer use a physically small inductor — typically a 1 µH or 2.2 µH chip inductor in a 0805 or smaller footprint. The high frequency also pushes the switching noise above the audio band and into a range where downstream filtering is simpler. Synchronous rectification is built in, so no external Schottky diode is needed. The internal low-side and high-side FETs handle the full 2.9A switch current, keeping the BOM count to just the inductor, input/output caps, and the IC itself.
9-pin DSBGA — layout considerations
The package is a 9-bump DSBGA (0.4 mm pitch, 0.25 mm ball diameter). The small footprint demands a solder-mask-defined pad layout and a stencil aperture that matches the datasheet recommendation. A 2-layer board can route the part if the ground plane is kept continuous under the package. The DSBGA package has no exposed thermal pad; heat is conducted through the solder bumps and the PCB copper.
Available in Tape & Reel (TR) for automated pick-and-place or Cut Tape (CT) for prototyping and small-batch builds. The base product number is TPS61256; the YFFT suffix denotes the DSBGA package and the specific test/binning variant.