The loop response of the TPS62148EVM-034 can be measured with two simple changes to the circuitry. First, install a 10-Ω resistor across the pads in the middle of the back of the PCB. The pads are spaced to allow installation of 0603-sized resistors. Second, cut the trace between the via on the VOS pin on the top layer and output capacitor. These changes are shown in Figure 1-1. With these changes, an ac signal (10-mV, peak-to-peak amplitude recommended) can be injected into the control loop across the added resistor.

Figure 1-1 Loop Response Measurement Modification