2 A buck at 570 kHz — the power-stage reality
The TPS54231DR is a non-synchronous step-down regulator that delivers 2 A continuous output from a 3.5 V to 28 V input rail. The 570 kHz switching frequency keeps the inductor small — typically 10–22 µH for a 5 V output — but the external diode and catch-diode losses mean efficiency tops out around 85–90 % at full load, not the 95 % you get from a synchronous part. The 8-SOIC package with exposed pad on the bottom dissipates heat into the board copper — a 2-layer board with a 1-inch² copper pour keeps the junction below 125°C at 2 A.
Input-range flexibility vs. thermal budget
With a 3.5 V minimum input, this part runs directly from a 5 V rail or a 3-cell Li-ion battery; the 28 V maximum handles 24 V industrial supplies without a pre-regulator. The 150°C junction rating gives headroom for high ambient, but the non-synchronous topology means the catch diode and inductor DCR eat into that margin at full load — expect 2–3 W of total loss at 2 A out, 12 V in. Compared to the synchronous LMR33630APCQRNXRQ1 (2.1 MHz, 3 A, synchronous), the TPS54231DR runs a lower frequency and lacks synchronous rectification, so it trades efficiency for simplicity and a wider input range. The LM53625LQURNLRQ1 (2.5 A, fixed 5 V output) is a drop-in alternative only if you need a fixed rail — the TPS54231DR's adjustable output covers more use cases.
The 8-SOIC package is widely second-sourced by other manufacturers, but Texas Instruments has not published a formal cross-reference to an alternative MPN. For a long-life BOM, confirm the date code and supply continuity at quote time — no single-source risk flags today, but the non-synchronous topology means a synchronous replacement would require a new inductor and layout.