I'm struggling a bit identifying appropriate buck. Here's the requirements:
VIN=10-40V, nominal 24V
VOUT = 1.8V
IOUT = 20mA max, 5mA nominal
I've currently got this implemented with TPS54061, but the problem is that I originally designed for the full 200mA capability of the part in DCM, but under real load conditions (much lower, more like 5mA), I get pulse-skipping. This is creating noise in band of interest (10-40kHz) that is coupling into sensitive signal conditioning circuitry. Using TPS54061 design spreadsheet, I can't solve for DCM solution at this light load and avoid pulse skipping. There seems to be solution for CCM, but then again, TPS54061 doesn't have all that low IQ to begin with.
Does anyone have any suggestions for a high conversion ratio buck, low output current, that isn't going to generate all sorts of skip/pulse/ECO mode noise in the 10-40kHz region?