The NFCT antenna coil must be connected differential between NFC1 and NFC2 pins of the device.
Two external capacitors should be used to tune the resonance of the antenna circuit to 13.56 MHz.
The required tuning capacitor value is given by the below equations:
An antenna inductance of Lant = 2 μH will give tuning capacitors in the range of 130 pF on each pin. The total capacitance on NFC1 and NFC2 must be matched.