NFC Tag Reader : Working Principles, Block Diagram and Key Differences

Near Field Communication (NFC) has become an essential part of modern wireless communication, enabling devices to exchange information by simply bringing them close together. NFC tag readers play a crucial role in reading and processing the data stored in NFC tags, used across industries like retail, healthcare, and transportation. This guide describes working of NFC tag readers, breaking down their core components with a detailed block diagram for a clearer understanding of the technology behind this seamless communication. It also highlights difference between NFC tag and NFC reader.

Working of NFC Tag and reader

NFC network consists of two devices viz. initiator and target. There are two basic modes of operation in NFC network known as active and passive. In NFC active mode, both initiator and target devices will have their own power supply or battery for operation. In NFC passive mode, one of the NFC device will have power of its own while other device is full passive and derive its power from active powered device.

Both NFC tag and NFC reader communicates using 13.56MHz frequency for operation. They use ASK modulation for modulating the data to be transmitted before being translated on RF carrier of 13.56MHz. The NFC devices utilize concept of electromagnetic induction between loop antennas for connecting.

What is NFC Tag ?

Figure-1 depicts internal block diagram of NFC tag device. NFC tag usually consists of EEPROM, processor or microcontroller unit, anti-collision algorithm, authentication and cryptographic mechanism, RF interface circuit, RF antenna operating at 13.56MHz etc.

There are different types of tags developed based on various applications of use such as type-1 tag, type-2 tag, type-3 tag, type-4 tag and type-5 tag (known as Mifare classic tag). Following are the generic parameters of NFC tag considered during selection process:
• NFC Tag can be either active or passive device.
• Memory storage limit
• speed of operation
• Data access mode read/write or read only.
• collision mechanism
• price
➨Refer difference between NFC tag types➤.

Usually NFC tags are available which transfer data at the rate from 106 kbps to 424 kbps.

What is NFC Reader ?

Figure-2 depicts internal block diagram of NFC reader device. NFC reader usually consists of microcontroller unit such as LPC series, NFC reader IC, antenna matching circuit, 13.56MHz loop antenna etc. Popular reader ICs used in NFC reader are CLRC663, PN512, SLRC610, PR601, MFRC522, PN7120 etc. developed by NXP semiconductor.

Following are the generic features of NFC reader:
• NFC reader is always an active device.
• Host interface e.g. SPI, I²C, RS232, UART etc. are available.
• EEPROM is used to store NFC protocol and commands.
• FIFO (i.e. buffer) is used to handle transmit and receive data frames.

Difference between NFC tag and reader

Following table compares NFC tag vs reader with respect to various parameters.

Conclusion

NFC tag readers play a critical role in the evolving landscape of contactless communication. By understanding their working, block diagram, and the differences between various NFC types, it's easier to see how they contribute to the efficiency and security of modern data exchange systems. As NFC technology continues to grow, its applications will only become more versatile and widespread.

NFC technology related links

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RF and Wireless Terminologies