Input range and output — what the 28 V / 3 A rating means on your bench
The TPS54331GDR accepts a 3.5 V to 28 V input and delivers a regulated adjustable output down to 0.8 V at up to 3 A.
Non-synchronous topology — the external diode is your call
This is a non-synchronous buck — no internal low-side FET. You supply the Schottky catch diode. The diode's forward voltage and reverse recovery charge directly affect efficiency at light load and thermal stress at full load. For a 3 A output, a 5 A-rated Schottky with a Vf below 0.5 V is the usual starting point. Eco-Mode™ pulse-skipping at light loads reduces switching losses, which helps meet standby-power targets in always-on equipment like base-station power supplies or industrial sensor nodes.
The base product number TPS54331 covers multiple package variants, so the 8-SOIC version is a standard catalog item.
8-SOIC footprint — layout notes for the 3 A rail
The 8-SOIC package has a 0.154-inch body width and 1.27 mm pin pitch — a standard footprint that routes easily on a two-layer board. No exposed thermal pad; the die heat flows through the leads and the copper pour on the solder side.