Contactless Module Extends Secure Payment to Wearables

STMicroelectronics offers the ST53G System-in-Package for easy and secure contactless transactions using popular wristbands or fashionwear like watches or jewelry. The solution combines a miniaturized and enhanced NFC radio with a secure banking chip in one compact 4 mm x 4 mm module. The company’s proprietary boostedNFC technology allows wearables with small antennas to deliver a satisfying user experience when interacting with card readers over typical contactless distances.

 

The simplicity of the all-in-one module helps card manufacturers to quickly introduce functional and attractive wearables that can range from fashion items to one-time devices like event wristbands. ST offers an extensive development ecosystem, including radio-tuning tools and pre-defined antenna configurations.

 

The ST53G meets all relevant card-industry standards, including EMVCo compliance, ISO/IEC-14443 NFC card emulation, and MIFARE ticketing specifications and can host ready-to-use STPay smartcard operating systems and optional VISA/Mastercard/JCB-certified banking applications pre-loaded on the secure microcontroller.

 

The secure banking chip features a secure architecture with a NESCRYPT coprocessor for public-key cryptography and hardware accelerators for algorithms like AES and triple-DES. Extensive anti-tamper protection including an active shield, environmental monitoring, a unique serial number for each die, and protection against numerous other attacks is also built-in. These features complement software-based security running on the SC000 core to ensure the strongest possible protection for users’ credentials.

 

The contactless IC is the STS3922 RF booster, which uses active-load modulation (ALM) to maximize transaction range and omnidirectional radio performance in card-emulation mode. This enables wearable devices to be easy to use, with equal or better device-to-reader positioning tolerance than conventional contactless smartcards, even though a smaller antenna is used. Using ST53G contributes to final device cost optimization, as small antennas can be etched onto the PCB at almost zero additional cost. In some cases, a challenging metallic case can itself be used as part of the RF antenna.

 

In addition, automatic power and gain control, configurable sensitivity, and configurable signal/reader-field phase difference ensure consistent communication over all ranges while enhancing interoperability with different types of readers and terminals including various types of transportation ticketing systems. The STS3922 has inherently low power consumption, and a dedicated secure-microcontroller wake-up output allows the ST53G System-in-Package to maximize battery life by powering down when not in use. For more details, contact STMicroelectronics.