I recently acquired some Mifare DESFire EV1 ICs (MF3MOD8101DA4 in PLLMC format) to do some R&D with. I anticipated being able to use some of NXP's antenna design guidelines to prototype a loop antenna with some coil with the chips; I haven't had any luck though. I also purchased some working DESFire ID cards (full system of DESFire EV1 and loop antenna) that are readable on an Android phone. I ended up opening up the ID card, desoldering the working IC and soldering on the chip that I bought. That didn't work either, no reading on the Android device. Soldering back on the original IC in the ID card and it was working again. So the PLLMC chips never worked.
I'm wondering if there is some sort of initialization or factory reset that needs to take place on new DESFire chips, or are they just supposed to work immediately with an appropriately tuned antenna?
