Passive NFC with Variable Resistor as an Analog Input

[oseania]

Hi,

We have an size critical application in which we intend to use passive NFC (there is no room for battery). In the application we have a one variable resistor which value we would need to transmit using NFC. Considering that our signal is analog we are now asking if there is any smart way to feed the signal to NFC IC which could subsequently transmit it? We started thinking about oscillators where the varistor would change the frequency.

We haven't yet selected the NFC IC and if there is some certain NXP product that would fit here, we would love to hear about it.

[Kan_Li]

Hi Sami,

I would recommend NTAG I2C Plus for your application, it has a passive NFC interface with a contact I²C interface, also has the energy harvesting capabilities to provide power for a host like MCU. You may transfer the value via NFC, when the NTAG I2C Plus receives the data , it signals to the host thru an IRQ line, and then the host starts to fetch the data via I2C port. This product supports XQFN8 package which is 1.6 x 1.6 x 0.6 mm, recommended for size critical applications.

Please kindly refer to NT3H2111/2211|NXP  for more details.

Hope that helps,
Have a great day,
Kan

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