Electronic – LDO Bypass and Output Capacitors


I'm using an XC6210B332MR-G 3.3v LDO and I want to ensure good resistance to transient ringing at boot. The datasheet stipulates a bypass and output capacitance of at least 1uF for 1.8+v output. Would there be any downsides to using a 22uF X5R MLCC? I've done some research and from what I understand, larger capacitance values will help reduce the load transient.

Best Answer

A larger capacitor is likely to have somewhat worse high-frequency performance than a smaller cap, so I’d suggest using a 22u in parallel with the recommended 1u. Depending on the load characteristics you might consider a 10n cap in parallel too. You’ll want the 1u cap closest to the regulator. The data sheet doesn’t indicate any issues with using a larger capacitance, and indeed it’s recommended for loads with big transients. X5R is a good choice of dielectric for this application.