Hi, I am using MPQ4323C for a 20V-5V buck. input is variable 12-20 Volt, after 18 Volt in put Vsw and Isw is not stable. Noise is observed. at no load and load conditions. Please give any suggestions .
You did something wrong. You are going to need to provide more detail if you expect any meaningful comment. Do you have a demo board to compare against? Is the a schematic you can share, did you do the layout yourself?