Triple-output buck for multi-rail designs
The TPS65251-1RHAT is a triple-output step-down buck regulator from Texas Instruments, delivering 3A on one channel and 2A on the other two. The adjustable outputs can be set from 0.8V up to 17V, covering 1.2V core rails, 3.3V I/O, and 5V analog supplies from a single 4.5V to 18V input bus.
Switching frequency and thermal layout
A lower frequency improves efficiency by reducing switching losses; a higher frequency shrinks the inductor and output capacitor footprint at the cost of increased FET losses and tighter loop compensation.
Synchronous rectification and output configuration
All three channels use synchronous rectification, which eliminates the external Schottky catch diode and improves efficiency at higher output currents. The outputs are positive and adjustable, with a minimum reference of 0.8V. The 3A output is typically assigned to the highest-current rail (e.g., 5V or 3.3V), while the 2A channels handle lower-power loads.