TPS54260-Q1: How to choose a Schottky diode

Hi Jeffrey,

The role of the Schottky is to allow for the conduction of the free-wheeling inductor current when the high-side switch of the buck converter is off.

Usually you would just want to make sure that the reverse voltage that is equal or greater than Vinmax. Peak current rating of the inductor is greater than the maximum inductor current. Personally, I would want a diode that has a DC current rating of at least 1.5x the maximum output current. To minimize conduction loss, the forward voltage of the schottky is usually lower. A large package size helps with thermal characteristics.

For a general schematic review, I would make sure to see if the inductor's saturation current is above the device's peak current limit, and to generally see if the boot/input/output capacitance values are within range (you can compare with the existing application design). Also, I would check the voltage derating of the ceramic capacitors- the usual rule of thumb is to select components with 2x the voltage across it for ceramic capacitors. 

Thanks,

Richard