SNVSCU3 October 2025 LM5137
PRODMIX
Figure 8-20 shows the schematic diagram of a single-output, two-phase synchronous buck regulator with an output voltage of 12V and rated load current of 20A. In this example, the target half-load and full-load efficiencies are above 95% based on a nominal input voltage of 48V that ranges from 36V to 65V, with transients to 20V and 72V. The switching frequency is set at 400kHz by resistor RRT. Bias power derives from the 12V output, thus improving light-load efficiency. RFB of 48.7kΩ (connected from FB1 to VDDA) establishes a fixed output setting of 12V.