I am using the PMP20058 PoE Isolated Flyback Reference Design with the LM5022 to convert 12V to 54V. I have two PCB designs with the same circuit, though not with the same layout. At high current draw, one of the two PCB designs generates an audible noise that gets higher in frequency with higher current draw.
I find that just by touching my scope probe to the RT/SYNC input, the audible noise goes away, and the OUT pin returns to the 100KHz PWM rate. Without the scope on the RT/SYNC input, the OUT pin pulse rate appears to be faster.
Any ideas?
