NXP - ICODE 3

The ICODE 3 family comes in two references built on the same silicon, which share the memory, the protocol and the whole set of protections:

The TagTamper version adds two dedicated pads, connected to a conductive wire running across the seal or the packaging. Used as a Type 5 NFC tag, the 300 bytes host an NDEF message representing a URL of around 280 characters, enough for a richly parameterized link or a complete vCard.

The memory of the ICODE 3 is split into two distinct spaces, user and configuration, addressed by different commands:

Segmentation is the strong point of this generation: a pointer splits the user memory into two pages of free size (Page L and Page H), each receiving its own read and write rights. A single label can thus publicly expose its NDEF message and reserve the rest for the application. On delivery, the memory is blank, no protection is active and the passwords are set to zero.

• SELFAdjust, automatic tuning: at each power-up, the chip tunes its own RF performance to the optimum for the environment it finds itself in: the same label therefore works on very different materials, which considerably simplifies design and industrialization.
• Range and speed: up to 1.5 meters at a gate and a fast read up to 212 kbit/s (eight times the standard ISO 15693 data rate), with true anticollision and a persistent quiet mode for mass inventories.
• Six 32-bit passwords: read, write, privacy, destroy, EAS and AFI, configuration: each function has its own, and an optional mode raises memory protection to 64 bits by requiring both the read and write passwords.
• Programmable authenticity signature: delivered with a 32-byte NXP signature based on elliptic curve cryptography (secp128r1 curve), it can be replaced with an issuer-specific signature, extended to 48 bytes if needed, and then permanently locked.
• 24-bit counter and ASCII mirrors: the counter can be configured as a command-based counter or as an NFC counter that increments automatically at each tap; the mirrors copy the identifier and the counter value in plain text into the message being read, for online verification at every tap, without rewriting the chip.
• Two privacy modes and a destroy function: the first mode silences the chip to everything except the presentation of the password, the second makes it answer with a neutral shared identifier; the destroy command, for its part, deactivates the label permanently.
• TagTamper (SL2S3003TT): at power-up the chip detects whether the seal wire is intact or broken, distinguishes the current status from the stored one, and can reveal a pre-programmed 4-byte message, visible only after the first opening.

To this are added EAS anti-theft with its selective identifier, the AFI and DSFID registers for application sorting, a global locking command for fast encoding in production, and integrity ensured by a 16-bit CRC check. Target applications range from product identification and traceability to counterfeit and tamper protection, inventory management, consumables for connected machines and mobile interaction.

The ICODE 3 uses NFC-V technology (ISO/IEC 15693), supported by the vast majority of recent NFC smartphones. On Android, reading and writing work natively with NFC Tools, without any particular restriction. On iPhone, automatic background reading is available from the iPhone XS and XR onwards; models from the iPhone 7 can read and write the chip via NFC Tools on iOS 15.6 or later, by starting the scan manually from the app.

With NFC Tools, the ICODE 3 chip supports reading technical information, reading and writing NDEF records, erasing and locking. The passwords, the protected pages, the counter, the mirrors, the privacy modes and the TagTamper feature are managed through the chip's dedicated commands. The list of compatible models is available in the article on compatibility.

The ICODE 3 is fully backward compatible with the SLIX2: infrastructures already in place keep working, and the new generation adds speed, automatic tuning, memory segmentation and native NFC features. The only concession is its slightly smaller user memory, as the counter raised to 24 bits takes up one more block. On the STMicroelectronics side, the ST25TV family covers the same ground, as does the EM4237 at EM Microelectronic.

How much data can be stored on an ICODE 3?

The chip offers 300 bytes of user memory (2,400 bits in 75 blocks of 4 bytes), i.e. a URL of around 280 characters in NDEF usage, a complete vCard or a richly parameterized link. An additional block hosts the 24-bit counter.

What is the SELFAdjust mechanism for?

Automatically tuning the chip's RF performance, at each power-up, to the environment it finds itself in. The same label thus keeps good performance whether it sits on cardboard, plastic or a difficult material, without designing one antenna per material.

Is the ICODE 3 compatible with iPhones?

Yes. Background reading works from the iPhone XS and XR onwards, and both reading and writing are possible via NFC Tools from the iPhone 7 on iOS 15.6 or later.

Can an ICODE 3 be protected against rewriting?

Yes, on several levels: per-page write protection, reversible through the write password (or both passwords in 64-bit mode), and permanent block-by-block locking, which is irreversible, including from NFC Tools. A global locking command also makes it possible to freeze large sections quickly in production.

Official NXP datasheet (PDF)

Recommended NFC chips for NFC Tools

Buy ICODE 3 NFC chips