Datasheet

LM5118, LM5118-Q1
SNVS566G –APRIL 2008–REVISED FEBRUARY 2013 www.ti.com
SNUBBER
A snubber network across the buck recirculating diode reduces ringing and spikes at the switching node.
Excessive ringing and spikes can cause erratic operation and increase noise at the regulator output. In the limit,
spikes beyond the maximum voltage rating of the LM5118 or the recirculating diode can damage these devices.
Selecting the values for the snubber is best accomplished through empirical methods. First, make sure the lead
lengths for the snubber connections are very short. Start with a resistor value between 5 and 20 Ohms.
Increasing the value of the snubber capacitor results in more damping, however the snubber losses increase.
Select a minimum value of the capacitor that provides adequate clamping of the diode waveform at maximum
load. A snubber may be required for the boost diode as well. The same empirical procedure applies. Snubbers
were not necessary in this example.
26 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LM5118 LM5118-Q1