Fixed 1.6 V rail — confirm before you commit
The TPS62224DDCR is a fixed-output step-down (buck) converter from Texas Instruments, delivering a regulated 1.6 V rail. That output voltage is not adjustable — if your BOM calls for 1.8 V or 1.2 V, this is not the part. The 400 mA output current ceiling and 1.25 MHz switching frequency are the other two numbers that decide fit: the current must cover your load with margin, and the switching speed sets the inductor value and output ripple you'll design around.
With a 400 mA output and synchronous rectification, this converter keeps efficiency above 90% across most of its load range — the synchronous switch eliminates the external Schottky diode that older non-synchronous bucks need. The 1.25 MHz switching frequency lets you use a small inductor, typically 2.2 µH to 4.7 µH, keeping the overall footprint tight. Input range is 2.5 V to 6 V, so it runs from a single Li-ion cell or a 3.3 V / 5 V regulated rail.
SOT-23-5 Thin — board area and storage note
The SOT-23-5 Thin (TSOT-23-5) package is a surface-mount footprint about 2.9 mm × 1.6 mm — small enough for space-constrained portable designs. The reels are moisture-sensitive; store them dry or bake before reflow if the seal is broken.