Which is the typical value of the matching impedance that the ST25R3911B should see?

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I'm designing the NFC antenna, the EMC filter and the matching circuit, for an industrial NFC application. I'm looking for a good value of the matching impedance that provide the right tradeoff between performance and efficiency

ST25 NFC RFID Readers – ST25R391x series

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Travis PalmerBest answer

ST Employee

Hello,

The target matching impedance is commonly chosen by the available power budget - the power you want to spend when the reader is transmitting.

If there is no special power budget defined and there are no special requirements about read range, then a good target is around 20 to 30 Ohm. This should give a power consumption between 170mA and 140mA during constant wave.

Br Travis