Quad-rail power architecture — two bucks, two LDOs in one 5x5 mm QFN
The TPS51222RTVT packs four regulated outputs into a single 32-WQFN (5x5) package: two step-down (buck) controllers plus two linear (LDO) regulators. The two controller outputs are labelled simply 'Controller' in the spec — they drive external FETs for the high-current rails. The third output is a fixed 3.3V LDO rated at 10 mA, likely for a standby or always-on supply. The fourth output is a second LDO, though its voltage and current are not specified in the summary data.
Switching frequency and inductor sizing
The switching frequency is programmable from 200 kHz to 1 MHz via an external resistor or sync pin. At the low end you get better efficiency and wider input-to-output step-down ratios, but the inductor grows. At 1 MHz the inductor shrinks to a 2.2 µH or 3.3 µH chip — good for a compact layout — but switching losses in the external FETs rise. If you need AEC-Q100, this part is not the fit.
Package and hand-solderability
Without a thermal via array under the pad, the junction temperature rises quickly above 85°C at full load. Available in Tape & Reel (TR) for production pick-and-place or Cut Tape (CT) for prototyping and small runs. The reel quantity is not listed here, but the CT option lets you buy a handful for a breadboard build without committing to a full reel.
It is ROHS3 compliant, so no exemption issues for EU or California market shipments. If you need a drop-in alternative, the BOM is single-sourced to this part number.