st25r3916B Antenna tuning: which variable capacitor to use?

[smithderek2000]

Hello,

I'm working on a few designs that use the ST25R3916B. I've implemented the antenna match that incorporates 5 variable capacitors based on X-Nucleo-NFC08A1. In one reference design I see that you use the LXRW0YV201-059 but in a different reference design the LXRW0YV600-054 is used. Which is correct?

[Ulysses HERNIOSUS · Accepted solution]

Hi,

there is no correct or incorrect. The mentioned variable capacitors are different with regards to their capacitance values.

Which one you want to choose will depend on:

• your matching
• your antenna
• your goals what you want to achieve (compensate) with the antenna tuning during runtime.

Please take also into account that the capacitors have quite a substantial minimum capacitance (typically half of the max capacitance).

Best Regards, Ulysses

[smithderek2000]

Great, thanks. They look pin compatible so we will figure out which to use during testing.