🔬 Chip Encyclopedias

NXP's NTAG21x family (NTAG213, NTAG215, NTAG216) is the most deployed NFC Type-2 chip family on the planet. The workhorse silicon behind billions of review cards, event wristbands, loyalty touchpoints, anti-counterfeit labels and IoT pairing tags. This encyclopedia documents the three chips' memory maps page by page, the 13-command Type-2 command set with hex opcodes, the NDEF TLV framing rules, the mirror and counter features, the lock/CFG bytes, and the specific tradeoffs that decide when NTAG213 is enough and when NTAG215 / NTAG216 are required.

NTAG424 DNA (NT4H2421Gx / NT4H2421Tx) is NXP's flagship authentication NFC chip, combining ISO/IEC 14443-4 compliance, AES-128 cryptography and the Secure Unique NFC (SUN) message feature that generates a different, cryptographically signed URL on every single tap. Combined with CMAC (Cipher-based Message Authentication Code) verification, NTAG424 DNA is the technology that powers anti-counterfeit tags for luxury goods, EU Digital Product Passport implementations, tamper-evident seals and cryptographic brand-authentication campaigns. This encyclopedia documents the chip's architecture, memory layout, SUN/CMAC message format, key management, backend verification flow, and the specific commercial deployments where it is the correct engineering choice.

The legacy 13.56 MHz access-control chip is the HF 13.56 MHz chip that defined the first two decades of contactless access control. Shipping in volume since 1996, the 1K (MF1S50) and 4K (MF1S70) variants use the proprietary CRYPTO1 stream cipher, a sector-based memory model with per-sector key-A / key-B authentication, and the ISO 14443-A Part 3 anti-collision/UID layer. CRYPTO1 has been publicly broken since 2008, so Classic is no longer appropriate for new greenfield security-critical deployments. But the installed base is enormous (hotels, transit, corporate access) and Classic remains the reference HF chip for low-cost loyalty, membership, and legacy-reader compatibility programs.

The NXP MF3D(H)x2 — MIFARE DESFire EV3 — is the current flagship AES-128 enterprise smart-card chip: the silicon behind corporate access control, transit ticketing, closed-loop cashless payment, and multi-application campus credentials. This encyclopedia documents the full DESFire EV3 command set, the three-key AES authentication flow, the application and file-based access model, the MIFARE 2GO / transaction MAC / proximity-check features that EV3 introduced, and the migration path from DESFire EV1 and EV2. Intended as the day-to-day reference for reader firmware developers, SAM integrators, and access-control architects.

MIFARE Ultralight C (NXP MF0ICU2) is the low-cost, paper-ticket-oriented HF 13.56 MHz chip that brought triple-DES authentication to single-use and short-life credentials. Shipping since 2008, it extends the original Ultralight architecture with 144 bytes of user memory, 3DES mutual authentication (16-byte key, based on NIST SP 800-67 Triple DES), a one-way 24-bit counter for event-ticket validation, and the ISO 14443-A Part 3 layer. Used in event tickets, transport single-ride tickets, limited-edition gift cards, and any application where a paper-substrate HF chip with tamper-resistant authentication is needed.

This NXP HF Vicinity chip family (and its successor SLIX2) is the NXP HF 13.56 MHz chip optimized for ISO/IEC 15693 vicinity cards. Shipping since 2009, {chip:nxp-icode-slix:short_name} extends the original ICODE-1 platform with larger user memory (896 bits on SLIX, 2,560 bits on SLIX2), hardware-enforced EAS (Electronic Article Surveillance) for library-gate anti-theft, a built-in privacy mode, 64-bit password protection, and backwards compatibility with the worldwide installed base of ISO 15693 readers. It is the chip behind the vast majority of library-book tags, industrial laundry tunnels at the HF tier, museum exhibit tags, and large-inlay HF supply-chain tracking.

The {chip:impinj-monza-r6:name} family and its successor M700/M800 series are the defining UHF chips of retail-apparel item-level tagging. {chip:impinj-monza-r6:short_name} introduced AutoTune (a chip-integrated feature that auto-calibrates antenna impedance in the field) and AutoPilot power management. {chip:impinj-monza-r6-p:short_name} added extended user memory and a higher peak temperature rating. The {chip:impinj-m730:short_name} and {chip:impinj-m750:short_name} derivatives extend sensitivity further. This encyclopedia documents the five chips' specifications, the AutoTune mechanism, the FastID and TagFocus serialization features, and the deployment boundaries where each chip is appropriate.

{chip:nxp-ucode-8:short_name} (NXP SL3S1203 / SL3S1213) has been the cost-of-gravity UHF inlay chip since its 2017 launch. Shipping in billions of units per year, it powers the majority of promotional, event, single-use and cost-sensitive UHF deployments still converting today. This encyclopedia documents {chip:nxp-ucode-8:short_name}'s memory layout, EPC Gen2 v2 command support, sensitivity envelope, the {chip:nxp-ucode-8:short_name} versus {chip:nxp-ucode-8m:short_name} distinction, and the specific deployment classes where {chip:nxp-ucode-8:short_name} remains the correct choice in 2026 even as {chip:nxp-ucode-9:short_name} takes the sensitivity crown.

UCODE 9 (NXP {chip:nxp-ucode-9:partNumber}, with UCODE 9xe = {chip:nxp-ucode-9xe:partNumber} and UCODE 9xm = {chip:nxp-ucode-9xm:partNumber}) is the workhorse UHF inlay chip of the item-level retail era. Shipping since 2020, it extends the EPC Gen2 v2 standard with a best-in-class read sensitivity ({chip:nxp-ucode-9:read_sensitivity_dbm} dBm), a self-adjust sensitivity mode, a fast Session-0-to-Session-2 transition, optional Untraceable and Authenticate commands, and sufficient user memory for a {chip:nxp-ucode-9:epc_bits}-bit EPC plus backup serial data. It is the chip behind most of the retail apparel, linen-management, supply-chain, and library RFID volume shipped since 2021.

The 125 kHz LF (low-frequency) RFID chip family is the bedrock of legacy access control. Hotels, buildings, gates, car-park systems, pet microchips, and livestock tagging. {chip:em-microelectronic-em4100:short_name} is the read-only, Manchester-encoded 40-bit-ID reference chip shipping since the early 1990s. {chip:em-microelectronic-em4305:short_name} is its writable EEPROM cousin, still carrying the same air-interface compatibility. {chip:atmel-t5577:name} (originally Atmel, now part of Microchip) is the programmable 'universal LF emulator' that can be configured to impersonate {chip:em-microelectronic-em4100:short_name}, HID Prox, Indala, ioProx, AWID, and a dozen other proprietary LF formats. Together they cover the vast majority of deployed LF credentials worldwide.