Hi everyone. I am having a very frustrating issue of having my PCB 12 to 5v switching regulator failing after one day. I have tested the circuit and the PCB works for one day but then fails after the second day and the regulator output voltage is at 0.8v
The switching IC is MP1584EN buck converter steping down the 12v input to 5v for the microcontroller and other components.
Everything after the switching regulator on the 5v side is still working and if I power the 5v line from another power source directly there is no issues. Any thoughts on what this could be?
The 12v PCB end has a diode to prevent reverse polarity and a overvoltage crowbar circuit to prevent too high voltages from damaging the 12v circuitry so I don't think it is overvoltage damaging the switching regulator IC.
The power supply powering the 12v is also stable with no over voltage issues. When I power it up on a power supply bench it reads zero current, so nothing is shorting and no visible damage on the PCB or 12v circuitry. I have attached the 12v-5v switching regulator as well as the complete schematic as well.
If anyone has any ideas it would be really helpful.
Chris Riether

Complete PCB Design

 

Hi, i know long time passed, but i falling in same situation, i have totally messy behavior of same part, i copied schematic from small module, i made pcb, i put all parts from working pcb module, when i solder them on my pcb it work but strange, and on the end or it have some strange small voltage, or chip burn.... it is probably something regarding with pcb longer line then alowed but it is all small, i can't figure out what....
if you have some "magical" workaround please share with me (ara.techsupp(AT)gmai.com) thx..