8.2.2.14 R7, C11

A snubber network across the power diode reduces ringing and spikes at the switching node. Excessive ringing and spikes can cause erratic operation and couple spikes and noise to the output. Voltage spikes beyond the rating of the LM5575-Q1 or the re-circulating diode can damage these devices. TI recommends to select the values for the snubber through empirical methods. First, make sure the lead lengths for the snubber connections are very short. For the current levels typical for the LM5575-Q1, a resistor value between 5 and 20 Ω is adequate. Increasing the value of the snubber capacitor results in more damping but higher losses. Select a minimum value of C11 that provides adequate damping of the SW pin waveform at high load.