atmega 32U4 with ceramic resonator instead of a crystal ?

"modern" Arduino UNO's or e.g. the Arduino Pro have ceramic resonators* (with integrated capacitors) instead of a "real" crystal. *(e.g. Murata CSTCE16M0V53-R0)

I always thought, that due to the higher frequency inaccuracy and/or temp.-drift of the ceramic resonators, it should be used in applications only, where no high clock accuracy like baud-rate-generation is demanded ... (?)

As you can see on the UNO R3 the 16U2 for the communication uses a "real" crystal and the atmega328 uses a ceramic resonator.


now I am designing a very small leonardo (atmega 32U4) clone and I wonder if I can use a ceramic resonator instead of a "real" crystal (to save board space and component count) ? (each mm² counts)

Is this possible and what kind of disadvantages may occur then ?

What about the accurate (internal PLL ?) generation of the USB frequencies (48MHz/12MHz) then ?

[edit] I only found one single product yet, that uses a ceramic resonator with a atmega 32u4 --> https://www.pololu.com/product/3101 on the bigger variants of their boards --> https://www.pololu.com/category/149/a-star-programmable-controllers they use "real" crystals instead