quality factor of a decoupling capacitor at 1MHz

[devendra_devgupta]

decoupling capacitor

hi friends
what should be the quality factor of a decoupling capacitor at 1MHz

 

[vfone]

Re: decoupling capacitor

The reactance Xc of the decoupling capacitor should be less than 1 ohm at decoupling frequency.

At resonant frequency (SRF) the reactance of the capacitor is minimum, but also the Q is minimum.

To give an example:
A decoupling capacitor with SRF =10MHz, Xc@10MHz = 0.5 ohms, Q@10MHz = 1, can have Q@1MHz = 100.