My customer asks:
We have a load at 3v3 that takes from about 100mA to about 400mA, depending on what’s turned on.
We’re trying to step down from USB input, so a nominal 5v0, but ranging from 4v5 to 5v5.
Trying it out at the low end of the load, I had a load current of 136mA, and a source current of 130 mA with a 5v0 input. This gives me an efficiency of about 75%, when the data sheet would make me expect something in the low 90’s.
Circuit is very straight forward, pretty much right out of the data sheet.
LMR10510XMF
catch diode: MBRS2040LT3G (ONSemi)
Inductor: SRN4018-3R3M (Bourns)
2x 10uF ceramic input cap
2x 10uF ceramic output cap
Any ideas why I’m seeing such poor results?