[mikebounds]

I can find recommended inductance for NFC which seems to be 4.7uH which I guess will provide communication up to 5cm with maximum power and maximum data speed, but I cannot find minimum Inductance for NFC for:

1. Smaller distances, like actual contact to a few mm
2. Less power requirements (i.e not using NFC for charging)
3. Lower data speeds (i.e only transmitting a small amount of data or where slow speed is acceptable)

Does anyone know ranges of inductances that work for NFC and how this affects its use (data speed, charging rate). I found a small tag at https://www.adafruit.com/product/2800 which is only 15x6mm and from my calculations I reckon this is about 0.4uH so 10 times less than the recommended inductance and this tag does say:

Note that since the antenna is so small you'll need to put the tag right up against the device that's reading it
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So is having to hold this tag close to reader the only downside?

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