2334246_en-US

[#1]

Issues with writing via iPhone when the energy harvesting output is loaded

Issues with writing via iPhone when the energy harvesting output is loaded
Hello.

Everything works fine with Android. I am using the NFC TagWriter app. Testing was done on iPhone 7 and iPhone 16 Pro Max. The chip used is NTP5332.
Setup: https://www.nxp.com/products/rfid-nfc/nfc-hf/connected-nfc-tags/ntag-5-development-kits:OM2NTX5332?#...

Problem 1
If the energy harvesting output is loaded and the voltage does not rise instantly (in my case, a capacitor is connected to the harvesting output), even with a delay of about 1 second, the following happens:
When the phone is brought close (e.g., for NFC scanning), the RF field is present continuously, but the tag is not detected at all. The phone just shows the “hold near tag” message, and after some time it disappears.
If nothing is connected to the harvesting output except the NTP5332 chip itself, the iPhone reads and writes the tag without any issues.

Problem 2
Even if the load is removed from the harvesting output, the NFC field is present only for a short time during read or write operations. As soon as the tag is read or written, the iPhone turns off the NFC field, which makes energy harvesting impossible.

Question
Is this behavior caused by the iOS system or by the application software?
What are the possible ways to solve these issues?

Re: Issues with writing via iPhone when the energy harvesting output is loaded

Hello @Volodymyr1

Hope you are doing well.

There are some limitations related to iOS itself (such as immediate termination of NFC reader session). Perhaps the application expects an NDEF message; you can do some tests by writing a properly formatted NDEF to the NTAG 5 and then trying to read it.

Regards,
Eduardo.