About 2.2.4 in datasheet of ST25R3916

[DSai.1]

Dear Sir,

When I read 2.2.4 in the datasheet, there is a Note as

Using hardware based wake-up in combination with the automatic antenna tuning feature is

not recommended. Contact your nearest ST office for further support.

Could you tell me where I can find more information about the reason?

What kind of wake-up is referred to in this note? is it the low power card detection

mentioned in capacitive sensor (4.2.4)? or Wake-up mode in 4.2.5?

Are the above functions unavailable, if automatic antenna tuning is used?

best regards

Dai

[Ulysses HERNIOSUS]

Hi,

please see AN5320 ch.6. Yes it is about 4.2.5.

BR, Ulysses

[DSai.1]

Dear Ulysses,

thank you very much for your advice. I read the document and got the points.

By the way, I wonder if we should use AAT function for our application. Could

you explain the typical application cases in which the AAT is necessary to

adopt for a better performance?

best regards

Dai

[Ulysses HERNIOSUS]

Hi Dai,

typical usage of AAT is to deal with variations, this can be manufacturing variations (e.g. part to part, board, etc), environment variations (e.g. temperature, foreign objects), coping with load from target devices, etc.

Regards, Ulysses

[DSai.1]

Dear Ulysses,

thank you very much for your kind explanation.

no problem about this subject.

best regards

Dai Sai