Did you ever wonder how much current you can draw from the energy harvested output of an NFC EEPROM? I did, and I built a board to measure it.

The ST25DV and NXP NTAG I2C PLUS are designed for the same antenna loading so I was able to design a board that would support both devices. The results were a little surprising. The NXP NTAG I2C PLUS does a much better job regulating the output voltage. The ST25DV starts at about 4V with no load, and drops off rather quickly. I could draw almost 5mA before dropping below the 2.7V minimum voltage of the WCH32V003 with the NT3H2211, but less than 4mA from the ST25DV. Based on this data, I switched my beeping, blinking business-card designs to the NT3H2211.

Learn more about the project on Hackaday:
https://hackaday.io/project/177897-beeping-blinking-business-card-badge-b4/log/221646-power-estimates