STMicroelectronics’ Secure NFC Chip Simplifies Matter Device Commissioning

STMicroelectronics has introduced the ST25DA-C, a secure near-field communication (NFC) device engineered to simplify device onboarding for the Matter smart-home standard. The device is notable as a commercially-available secure NFC chip fully compatible with commissioning over the NFC Transport Layer, a functionality newly specified within the Matter 1.5 standard.

STMicroelectronics has designed the ST25DA-C NFC chip for secure commissioning of Matter devices. Image used courtesy of STMicroelectronics

The ST25DA-C Secure NFC Chip

STMicroelectronics has designed its new ST25DA-C chip to serve as an alternative to conventional commissioning methods such as Bluetooth Low Energy, QR codes, or passcodes. A key technical advantage of the ST25DA-C is its ability to perform commissioning operations on devices that are not yet connected to main power. This battery-less connectivity is enabled through energy harvesting: the device draws the electrical current required for operation directly from the radio frequency field generated by the tapping smartphone. This capability significantly improves the installation process for devices like wall switches or light fixtures that lack internal batteries and are often installed before power is available.

The ST25D’s NFC-enabled battery-less connectivity enables unpowered devices to be added to a smart home network. Image used courtesy of STMicroelectronics

Integrated Cryptography and Security

At its core, the ST25DA-C functions as a highly secure NFC Forum Type 4 tag, with integrated processing capabilities to support the complex cryptographic operations demanded by the Matter commissioning process. The device leverages STMicroelectronics’ expertise in secure elements, providing a secure storage environment for critical assets, including cryptographic keys, certificates, and network credentials. The chip is Common Criteria certified and meets the GlobalPlatform Security Evaluation Standard for IoT Platforms Level 3 requirements. 

Beyond commissioning, the ST25DA-C supports secure functions such as digital signatures, secure storage, and secure channel communication. The device also supports Matter signature generation and verification over its I²C serial interface, which runs up to 400 kHz.

Device Integration and Design

The ST25DA-C is designed for minimal physical footprint in space-constrained IoT applications. It is supplied in a compact 2.00 mm × 3.00 mm ultra-thin DFN8 package. Integration is further simplified by the inclusion of a 78-pF tuning capacitor, allowing designers to utilize highly integrated, smaller antennas.

The ST25DA-C simplifies smart home design for everything from lighting control to appliances. Video used courtesy of STMicroelectronics

The device can be powered either by its Vcc​ pin, with a supply voltage range of 1.62 V to 3.3 V, or contactlessly via the 13.56 MHz carrier. The chip incorporates more than 3 KB of non-volatile memory allocated for Matter certificates, keys, and attributes.

Simplifying Smart Home Design

The ST25DA-C chip provides a robust and secure foundation for deploying Matter 1.5-compatible devices, significantly simplifying the commissioning process. By enabling secure cryptographic verification using energy harvesting, the device addresses the practical difficulty of onboarding unpowered or hard-to-access equipment. This technology is suited for applications across the smart home and smart industry, including lighting control, access control systems, security cameras, and appliances.