SLUU286A March 2008 – October 2021 TPS54286 , TPS54386
TPS54386EVM contains a 51-Ω series resistor (R1) in the feedback loop to allow for matched impedance signal injection into the feedback for loop response analysis. An isolation transformer should be used to apply a small (30 mV or less) signal across R1 through TP6 and TP8. By monitoring the ac injection level at TP8 and the returned ac level at TP6, the power supply loop response can be determined.