Hello, Question Option Clock Oscillator for NFC ST25R3912 design.

[ADoan.1]

Hello, 

We used ST25R3912 for design NFC. Oscillator input capable of operating with 13.56

MHz or 27.12 MHz crystal with fast start-up in datasheet ST25R3912. But in my design we have source clock 19.2MHz. Can we use clock 19.2MHz replace clock 13.56MHz or 27.12MHz.

I have referred attached pdf file,

[Ulysses HERNIOSUS · Accepted solution]

Hi,

ST25R3911/12 etc are built for crystals of 13.56/27.12 MHZ and a carrier frequency of 13.56. There is the possibility to use an external clock like described here: https://community.st.com/s/question/0D53W00000CPX6qSAH/is-it-possible-to-use-a-clock-oscillator-instead-of-quartz-crystal-oscillator

However it is not built for running a carrier not equal to 13.56 MHz. And with a 19.2 MHz clock you would need to run the carrier at 8.6MHz (Runnig 19.2 MHz you will likely run into internal chip issues). Theoretically most of the time settings would shift as a result to the new fc. However that is probably not what you want to achieve:

You are falling out of ISM band and all existing infrastructure is only built/optimized/matched for 13.56 MHz.

Regards, Ulysses