On x-nucleo-nfc08a1 when to populate the second set of parallel variable caps?

[smithderek2000]

Hello,

In the x-nucleo-nfc08a1 reference design, there is the standard 3 variable cap setup (2 series, 1 parallel) plus also a second set of parallel vari-caps (C307 and the oddly named 4C30). But these are not populated on the board. Should we populate these in custom designs? In my design the antenna is a PCB trace coil about 0.75" in diameter but the trace length is about 10 inches and goes through a relay.

Thanks,

Derek

[Ulysses HERNIOSUS]

Hi Derek,

please see AN5322 chapter 5 for a discussion on usage of VCCs and different schematics.

BR, Ulysses