The circuit used to measure most switching parameters is shown in Figure 8-1. The top LMG352xR030-Q1 device in this circuit is used to re-circulate the inductor current and functions in third-quadrant mode only. The bottom device is the active device that turns on to increase the inductor current to the desired test current. The bottom device is then turned off and on to create switching waveforms at a specific inductor current. Both the drain current (at the source) and the drain-source voltage is measured. The specific timing measurement is shown in Figure 8-2. TI recommends to use the half-bridge as double pulse tester. Excessive third-quadrant operation may overheat the top device.