JAJSFS7B July 2018 – February 2019 LM5180-Q1
ADVANCE INFORMATION for pre-production products; subject to change without notice.
Select an input capacitance using Equation 23 to limit the ripple voltage amplitude to less than 5% of the input voltage when operating at nominal input voltage.
Substituting the input current at full load, switching frequency, peak primary current and peak-to-peak ripple specification gives CIN greater than 2 μF. Mindful of the voltage coefficient of ceramic capacitors, select a 4.7-µF, 100-V ceramic input capacitor with X7S dielectric10-µF, 50-V ceramic input capacitor with X7R dielectric in 1210 case size. The input capacitor RMS ripple current is given by Equation 24.