1 A fixed 12 V buck — the design-fit decision
The TL2575-12IKTTR is a 1 A step-down (buck) regulator from Texas Instruments with a fixed 12 V output. The 52 kHz switching frequency is on the low side by modern standards — the inductor will be physically larger than what a 200 kHz+ converter needs, but the switching losses in the internal BJT (this is a 2575-family part, not a MOSFET-based switcher) stay low, and the radiated EMI spectrum is easier to filter. Plan for a 100 µH to 330 µH inductor in the 1 A range. No synchronous rectifier is included, so an external Schottky diode (e.g., 1N5822 or SS34) is required between the switch node and ground. The diode's forward voltage and thermal rating set the efficiency floor at light loads.
DDPAK-5 — package and thermal reality
The DDPAK/TO-263-5 package (also called D²Pak, 5 leads plus tab) is a surface-mount power package. The PCB layout must connect this tab to a copper pour — a 1 oz copper plane of at least 1 in² per side keeps the junction temperature below 125 °C at full 1 A load in a 50 °C ambient. The 125 °C limit is the absolute-maximum junction temperature per the datasheet; the actual load current must be derated above 85 °C ambient based on the thermal resistance (RθJA) of the board layout.