I have designed this buck converter which was supposed to lower the input voltage range 13V - 15V to the 5V and should be capable of delivering 1.5A at 5V. It actually works okay with not load, I measure 5.17V, also works with small load. But when I connected actual load, which would draw current of 1.5A - something just happened, inductor started to make noise and the chip burned(although the white smoke did not left the chip).
Is it possible that this load has peak currents which are too big for the output capacitor? I wasn't able to power it from benchtop adjustable power supply which should be capable to supply 2A - although it works for few seconds on it and then restarts(it is Raspberry Pi with external LCD).
The component pick is coming directly from the TI WEBENCH tool. You can see them in schematics. The actual chip used is TPS563219. *9 is Bourns SDR0805-3R3ML inductor. C20 is C3216JB1A476M. C21 & C22 are GRM31CR61E106KA12L.
This is my schematics and board layout(2-layer, 1oz copper, made in Altium Designer). Beneath whole design there is clear copper pour connected to GND, with no other traces. (S1 is here for different reasons, not connected to the switcher design)
What might be wrong? Is it in peak currents that my load draws? Is the layout wrong at some part? Am I using the wrong chip? (I haven't tried connecting output to osciloscope before burning it).