ST ST25DA-C is an NFC chip with built-in support for the latest Matter 1.5 protocol, enabling easier installation of smart devices on home networks, including lighting, access control, security cameras, or any IoT device.
NFC here is used as an alternative to Bluetooth LE or QR core commissioning. NFC tap-to-pair functionality enables users to tap an NFC tag code on a device with their smartphone to securely and easily add it to their Matter-compatible app(s) and network(s). Besides batteryless commissioning, the ST25DA-C chip can also be used for firmware updates over I2C (Matter OTA), and secure storage for keys & certificates.
ST25DA-C secure NFC tag specifications:
- Contact interface
- 1.62 V to 3.3 V supply voltage range
- ESD protection
- Human body model (HBM): 6 kV for digital and antenna pads
- Charge device model (CDM): 1 kV based on a STMicroelectronics module
- I2C serial interface up to 400 kHz
- Contactless interface
- Power supplied by 13.56 MHz carrier
- Complies with ISO/IEC 14443 Type A
- Complies with NFC Forum Type 4 Tag (106/212/424/848 kbps)
- 78 pF tuning capacitor, with automatic antenna tuning for optimized performance
- Automatic CPU frequency adaptation for optimum power consumption
- 7-byte unique identifier (UID) on each die
- Matter services
- Stores Matter onboarding data in NFC Forum Type 4 tag
- Performs commissioning over NFC Transport Layer (NTL):
- Powered either by VCC pin or 13.56 MHz contactless carrier
- SPAKE2+
- Secure storage for certificates and keys needed for Matter commissioning
- Provides Matter signature generation and verification over I²C
- Memory – More than 3 KB of non-volatile memory allocated for Matter certificates, keys, and attributes
- Security features
- Secure MCU
- Active shield
- Monitoring of environmental parameters
- Protection mechanism against faults
- Protection against side-channel attacks
- Unique serial number on each die
- NIST 800-90B compliant true random-number generator (TRNG)
- Elliptic curve digital signature algorithm (ECDSA) with SHA-256 for digital signature generation and verification
- Elliptic curve Diffie-Hellman (ECDH) for key establishment
- Symmetric cryptography with AES-CCM for data confidentiality and integrity
- Symmetric cryptography with AES-CTR for data privacy
- Targets certification to the GlobalPlatform Security Evaluation Standard for IoT Platforms (SESIP level 3).
- Package – 8-pin UFDFPN8 (3 x 2 mm); ECOPACK2 compliant.
- Temperature Range – -25°C to +85°C
The setup process is described above: tap the NFC tag on your new device, connect it to its power (source mains or battery), and profit! We are also told that the ST25DA-C “features built-in equipment identification, streamlining installing multiple smart home accessories in parallel”. The way I understand is that if you have a kit with multiple devices, tapping a single NFC tag could add all of them to your Matter network. Other highlights are support for smart home devices from different manufacturers (more of a Matter attribute) and hardware protections for cryptographic keys and authentication credentials.
The main benefit here is that Matter devices don’t need Bluetooth LE radio just for provisioning and may feature a cheaper NFC tag instead. One potential downside is that while Bluetooth is supported in most (all?) phones, NFC is only supported in most (new) smartphones.
Key applications include lighting devices, HVAC and climate control, security and access control, appliances, media and entertainment, and environmental sensors.
The ST25DA-C samples are available now, and mass production is scheduled to begin in 2026. A few more details can be found on the product page and the press release, but detailed documentation, engineering samples, and evaluation kits would require you to contact one of ST’s sales representatives.
Thanks to TLS for the tip.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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