Other Parts Discussed in Thread: LM26420,
My circuit using LM26420-Q1, designed a way to output 3.3 V, the input is 5v, often there are veneer LM26420 SW pin resistance 4Ω or so (still work, only LM26420 extremely hot) or to the ground short-circuit situation. After the replacement of LM26420 phenomenon disappeared, the chip can work properly, SW impedance is normal. In normal operation, the current of 3.3 V is about 0.5 A.
Other output also used LM26420, output 2.5V 1.8V 1.2V 0.85V, etc. , but these voltage LM26420 controller did not appear a problem, so please help to see where my circuit design problem?
details sch and PCB shows as attachement, any advise? thanks in advance