The Topaz 512 is a piece of NFC history: designed by the British company Innovision Research & Technology (one of the technology's pioneers) and moved to Broadcom through the 2010 acquisition under the reference BCM20203T512, it is the great representative of the Type 1 Tag, the very first of the tag formats defined by the NFC Forum. Launched with 512 bytes (five times the memory of the original 96-byte Topaz) for business cards, smart posters and content delivery, it bets on a radically simple protocol, with 8-byte blocks and no anticollision. It remains readable and writable by the vast majority of recent NFC smartphones.
Information
| Manufacturer | Broadcom (designed by Innovision Research & Technology) |
| Family | Topaz |
| Reference | BCM20203T512 (Topaz 512) |
| Standard | ISO/IEC 14443A (levels 2 and 3) |
| NFC Forum type | Type 1 Tag |
| Operating frequency | 13.56 MHz |
| Data rate | 106 kbit/s |
| Unique identifier (UID) | 7 bytes, factory programmed |
| Operating distance | A few centimeters (up to 10 cm depending on the antenna) |
| Data retention | 5 years |
| Write endurance | 10,000 cycles |
| Memory | 512 bytes, including 480 user bytes |
Memory
The memory of the Topaz 512 carries the signature of Type 1: 8-byte blocks, split between a static area (inherited from the original Topaz) and a dynamic area organized in segments:
| Area | Content | Access |
|---|---|---|
| Block 0 | 7-byte UID and manufacturer data | Read only, set at the factory |
| User memory | 480 bytes in 8-byte blocks, static area then dynamic area in segments | Read / write; permanent static and dynamic locks |
| OTP area and locks | 8 one-way bytes and lock bytes | Bits that flip only once, with no way back |
Used as an NFC Forum Type 1 tag, the NDEF message can reach around 450 bytes, i.e. a URL of around 440 characters, a full vCard or a long text: the large memory of its era. Reading is performed block by block, by 128-byte segments, or in one go for the static area.
Features & security
- The radical simplicity of Type 1: a minimalist command set and the absence of anticollision (a single tag at a time in the field) made the Topaz line the most economical solution of its time, built for very large volumes.
- The large memory of its era: with 512 bytes, five times the original Topaz, it targeted business cards, automatic SMS sending, smart posters and digital content delivery: the founding uses of consumer NFC.
- Permanent locking: the static and dynamic locks freeze the memory area by area, irreversibly, and the 8 OTP bytes flip only once, for consumable rights.
- 7-byte UID: the unique identifier, written at the factory, serves data authentication and a light protection against cloning.
- The Innovision legacy: an NFC pioneer, the British company equipped the first sets of pre-programmed tags sold with the earliest NFC phones, before joining Broadcom in 2010: the Topaz tells the story of the technology's beginnings.
The Topaz line has since ended, and the chip now lives in existing stocks and fleets. Its 5-year retention and 10,000-cycle endurance, modest by today's standards, are a reminder of its age and reserve it for uses without longevity requirements.
Compatibility
The Topaz 512 uses NFC-A technology (ISO/IEC 14443A) and the NFC Forum's Type 1 Tag format, 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 Topaz 512 chip supports reading technical information, reading and writing NDEF records, erasing and locking. The list of compatible models is available in the article on compatibility.
Topaz 512 vs NTAG213
| Chip | User memory | Security | Typical use |
|---|---|---|---|
| Topaz 512 | 480 bytes | Permanent locks, OTP area | The Type 1 pioneer, existing fleets and stocks |
| NTAG213 | 144 bytes | UID and counter mirrors, 32-bit password | The current reference, Type 2 |
History has ruled: Type 2, carried by NXP's huge ecosystem, conquered the consumer tag market, and the Topaz line came to an end. The Topaz 512 keeps its generous memory and its pioneer status; for today's projects, the NTAG family is the way to go, with the NTAG215 offering comparable space (504 bytes) and the NTAG216 twice as much.
Frequently asked questions
How much data can be stored on a Topaz 512?
The chip offers 480 user bytes out of its 512 bytes, i.e. an NDEF message of around 450 bytes: a URL of around 440 characters, a full vCard or a long text.
What sets a Type 1 tag apart?
Its simplicity: 8-byte blocks, a minimalist command set and the absence of anticollision (the reader handles a single tag at a time in the field). The first format defined by the NFC Forum, it aimed for rock-bottom cost; Type 2 took over that role.
Is the Topaz 512 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 a Topaz 512 be protected against rewriting?
Yes: the static and dynamic locks freeze the memory permanently and irreversibly, including from NFC Tools, and the OTP bits flip only once. There is no reversible password protection: for that feature, an NTAG213 or ST25TA is the way to go.
