The TPS62821DLCR is a 1 A continuous-output synchronous step-down (buck) converter from Texas Instruments, switching at 2.2 MHz. The high switching frequency lets you use smaller inductors and capacitors — a 1 µH to 2.2 µH inductor and 10 µF output cap are typical — which shrinks the total solution footprint on a space-constrained board. Output is adjustable from 0.6 V up to 4 V via an external resistor divider, covering the common core and I/O rails for 1.8 V, 2.5 V, and 3.3 V logic.
The 8-VSON-HR package (2 mm × 1.5 mm) has an exposed thermal pad; the datasheet layout recommendation ties the pad to the ground plane with multiple vias to pull heat out of the die.