REF6041: Question about type of ceramic capacitor to use

Hi Jim,

You are correct that X7R capacitors can introduce piezoelectric effects into your system. If low noise is a critical concern for your design, choosing a capacitor that is not X7R could be helpful. The piezoelectric property of multilayer ceramic capacitors can introduce a µV range noise due to mechanical vibrations. More information on this can be found at these two links:

https://e2e.ti.com/blogs_/archives/b/precisionhub/posts/stress-induced-outbursts-microphonics-in-ceramic-capacitors-part-1

https://e2e.ti.com/blogs_/archives/b/precisionhub/posts/stress-induced-outbursts-microphonics-in-ceramic-capacitors-part-2

Ultimately, it depends on how noise sensitive your design is. REF6041 will have 12.288 µVpp typical noise from 0.1 Hz to 10 Hz, as noted in the electrical characteristics section of the datasheet. If you are concerned about the noise that the piezoelectric property will introduce in addition to the low frequency noise, then I would suggest using a different type of capacitor, as discussed in the links shared above. If you would like to further lower the noise in your design, we also have voltage references such as REF54410CDR and REF7040DGKR that offer even lower noise levels than REF6041, and are stable with loads as low as 1µF.

Thanks,

Jackson