STMicroelectronics ST25TB512-AC6G6

Overview

ST25TB512-AC6G6 from STMicroelectronics is a contactless 13.56 MHz ISO 14443-3 Type B memory IC with 512-bit EEPROM, 64-bit UID, dual 32-bit countdown counters, and built-in anticollision logic. It operates via RF energy harvesting, supports 106 kbit/s ASK/BPSK bidirectional data transfer, and features automated anti-tearing protection for counter writes. Used in reusable smart labels and secure NFC tag applications requiring deterministic write integrity.

For engineers reviewing the ST25TB512-AC6G6 datasheet, ST25TB512-AC6G6 pinout, ST25TB512-AC6G6 application, or ST25TB512-AC6G6 equivalent, key selection criteria include ISO 14443-2/3 Type B compliance, OTP lock register control, 1 million write cycles, 40-year data retention, and antenna interface requirements (AC0/AC1 pads with internal 68 pF tuning capacitor).

Technical Context

The ST25TB512-AC6G6 implements a probabilistic anticollision protocol using Slot_marker commands and 8-bit Chip_ID randomization, enabling multi-tag environments. Its RF interface uses 10% ASK modulation at 13.56 MHz for reader-to-tag communication and 847 kHz BPSK subcarrier load modulation for tag-to-reader response.

Memory is partitioned into three functional zones: five 32-bit resettable OTP blocks (0–4), two 32-bit decrement-only binary counters (blocks 5–6), and nine 32-bit EEPROM user blocks (7–15) with per-block write protection controlled by OTP_Lock_Reg bits b16–b31. All Write_block operations include auto-erase for EEPROM and reload-mode erasure for OTP when counter 6's b31–b21 are modified.

Key Specifications

Pinout & Package

ST25TB512-AC6G6 is supplied as a bare die (unsawn wafer or bumped and sawn wafer) with two RF antenna terminals only - no conventional IC package or power supply pins. It derives operating power entirely from the 13.56 MHz magnetic field via inductive coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar contactless memory applications.

Compared with ST25TB512-AC6G6, ST25TV02K-AC6G6 offers greater memory density but omits deterministic countdown and OTP reload-critical for asset lifecycle management. NT3H2111W0FHKH adds NDEF and I²C flexibility but shifts counter logic to host firmware, increasing system complexity and reducing atomicity guarantees.

Availability

ST25TB512-AC6G6 is available at Aetrix Electronics and suitable for reusable asset tagging, secure access credentialing, industrial tool tracking, and NFC-enabled calibration certificate applications requiring stable component supply across extended product lifecycles.

Supply support for ST25TB512-AC6G6 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, analog ICs, MEMS, and secure NFC solutions for industrial, automotive, and IoT markets.

ST25TB512-AC6G6 belongs to the ST25TB family of contactless Type B memory chips engineered specifically for high-reliability, battery-free identification and data logging in harsh or maintenance-constrained environments.

FAQ

Does ST25TB512-AC6G6 require an external power supply?

No. The device operates solely on harvested RF energy from a 13.56 MHz magnetic field. It contains an internal voltage regulator that powers the EEPROM, logic, and RF interface. No VDD, VSS, or external biasing is needed-only AC0 and AC1 antenna connections are required for operation.

How is write protection enforced on EEPROM blocks 7–15?

Write protection is controlled by the OTP_Lock_Reg located at block address 255. Bits b23–b31 correspond to blocks 7–15: setting any bit to 0 permanently locks its associated block. Once locked, the block behaves as ROM and cannot be unlocked. Activation requires issuing a Select command with a valid Chip_ID after modifying OTP_Lock_Reg.

What happens if power is lost during a counter decrement operation?

The ST25TB512-AC6G6 employs automated anti-tearing logic for both counters. If power drops mid-write, the counter value remains unchanged-the new value is only committed upon successful completion. This guarantees monotonic decrement integrity even under unstable RF field conditions.

Can the 64-bit UID be rewritten or cloned?

No. The 64-bit UID is factory-programmed into ROM and is read-only via the Get_UID command. It cannot be altered, erased, or duplicated. The UID is globally unique per die and serves as a cryptographic binding anchor for secure applications such as access credentials and calibration certificates.