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LM5175 malfunction

Other Parts Discussed in Thread: LM5175, LM5175RHFEVM-HD

Hi, 

I'm testing a new PCB design based on TI's LM5175, and it seems to have a highly unstable behaviour at higher load currents (>2A). It's desgined to output up to 5A @ 12V and input voltage range is 9V to 36V. The design it's based on TI's simulation workbench. 

As I've descrived, buck and boost operations work properly as long as output current is lower than 2A aprox, beyond that, unpredictable behaviour appears, and makes the output stard swtiching and eventually, going down to 0V. 

After analyisis, I compared the EVM's components with the ones of the simulation, and they are quite different, specuially the output capacitance.. I then change som compoenents but results are steel the same.

It seems its something noise related, but I'm not sure.

I attach the schematic design and a captrue of Vout (12V) and SW1 pin, becase there's a strange spyke of aprox 8,5V only when Iout >2A aprox.

I would really thank any quind of indications.