I'm using a step-up DC/DC converter (https://www.torexsemi.com/file/xcl101/XCL101.pdf) in my circuit to boost a 1.5V AAA battery voltage to 3.3V. The 3.3V is powering an audio circuit, and I heard a lot of noise in the audio signal. I suspected the issue was a noisy power supply, so measured the 3.3V voltage on the scope, AC coupled:
Disregarding the spikes, the peak to peak ripple is about 40 mV. Would you expect this level of noise ripple at the output of a DC/DC step up converter?
I'm not sure of the cause of the large spike, but it looks unrelated to the constant 40 mV noise on the 3.3V voltage.
This is the configuration I'm using for the 3.3V step up converter (from the datasheet):
The only thing I can think of that might help is using different capacitors. Right now I'm using ceramic 0603 capacitors (https://www.digikey.com/product-detail/en/murata-electronics-north-america/GRM188C81C106MA73D/490-7198-1-ND/3900421). The 3.3V step up converter's datasheet also recommends ceramic 0603 capacitors, however I noticed the specs for them indicate "Low ESL" (https://www.digikey.com/product-detail/en/tdk-corporation/C1608JB1A106K080AC/445-11201-2-ND/3948437). I'm not sure if using this recommended capacitor will make that much of a difference...could this be the problem?