The ST25R3911-BQFT is an NFC (Near Field Communication) reader chip designed by STMicroelectronics. It supports Type 1, 2 and 4 NFC tags, contactless transactions with NFC phones, and secure NFC transactions. It also comes with a range of integrated functions such as security protection, card emulation, anti-tearing, and anti-collision. Along with basic NFC functions, the chip also provides an AES engine to support secure transactions and NFC Type 4 Card Emulation in both host-controller mode and in device-host mode. It is offered in very small packages and with an embedded voltage regulator, allowing the use of a single power supply.