ST25TB04K datasheet(2/47 Pages) STMICROELECTRONICS

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Description

The ST25TB04K is a contactless memory, powered by an externally transmitted radio wave. It contains a

4096-bit user EEPROM. The memory is organized as 16 blocks of 32 bits. The ST25TB04K is accessed via

the 13.56 MHz carrier. Incoming data are demodulated and decoded from the received amplitude shift keying

(ASK) modulation signal and outgoing data are generated by load variation using bit phase shift keying (BPSK)

coding of a 847 kHz sub-carrier. The received ASK wave is 10% modulated. The data transfer rate between the

ST25TB04K and the reader is 106 kbit/s in both reception and emission modes.

The ST25TB04K follows the ISO 14443 - 2 Type B recommendation for the radio-frequency power and signal

interface.

Figure 1. Logic diagram

AC1

ST25TB04K

AC0

Power

Supply

Regulator

BPSK

Load

Modulator

ASK

Demodulator

4 Kbit

User

EEPROM

The ST25TB04K is specifically designed for short range applications that need re-usable products. The

ST25TB04K includes an anticollision mechanism that allows it to detect and select tags present at the same

time within range of the reader. The anticollision is based on a probabilistic scanning method using slot markers.

Table 1. Signal names

Signal names

Description

AC1

Antenna coil

AC0

Antenna coil

The ST25TB04K contact-less EEPROM can be randomly read and written in block mode (each block containing

32 bits). The instruction set includes the following nine commands:

•

Read_block

•

Write_block

•

Initiate

•

Pcall16

•

Slot_marker

•

Select

•

Completion

•

Reset_to_inventory

•

Get_UID

The ST25TB04K memory is organized in three areas, as described in Table 3. ST25TB04K memory mapping.

The first area is a resettable OTP (one time programmable) area in which bits can only be switched from 1 to 0.

Using a special command, it is possible to erase all bits of this area to 1. The second area provides two 32-bit

binary counters which can only be decremented. The last area is the EEPROM memory. It is accessible by block

of 32 bits and includes an auto-erase cycle during each Write_block command.

ST25TB04K

Description

DS11364 - Rev 7

page 2/47

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