What is an NFC tag?
Imagine an NFC tag as a very small memory card (something like a USB stick) that is equipped only with an antenna for wireless data transfer. The advantage is that an NFC tag does not need to have a built-in battery to power it continuously; it can in fact be charged simply by a mobile phone appearing in its close proximity.
Usually you will encounter an NFC tag in the form of a sticker the size of an ordinary postage stamp. It can, however, also be integrated into various key fobs, wristbands and many other things.
Besides the antenna, at the core of every NFC tag, sticker or product there is an NFC chip, i.e. an integrated circuit (IC). These tiny electronic devices contain all your information and control the options for accessing it.
Different NFC chips have different memory sizes and configurations, which affects the amount of information that can be stored on the chip, but also the way in which your data can be locked on the chip, and other important factors.
Among the best-known manufacturers of quality chips are the companies NXP Semiconductors and Broadcom.
Choosing the right tag
In the overall range of NFC tags and other NFC products there are several different kinds, which differ in their characteristics. At present, among the most used tags are the NTAG203, Ultralight, Mifare 1K and Topaz 512. The following table should help you to get a better idea of which tag is suitable for your particular needs.
| Popular NFC tags | ||||||
| Ultralight | NTAG203 | NTAG210 | NTAG213 | NTAG215 | NTAG216 | |
| Memory size (1) | 64 | 168 | 80 | 180 | 540 | 924 |
| (in Bytes) | ||||||
| User memory (2) | 48 | 144 | 48 | 144 | 504 | 888 |
| (in Bytes) | ||||||
| URL length (3) | 41 | 132 | 41 | 132 | 492 | 854 |
| (number of characters) | ||||||
| Best use | A cost-effective tag, suitable for short URL addresses. Placed mainly in wristbands, key fobs or promotional items. | A popular, general-purpose tag with a good URL length and an attractive price given its characteristics. | A cheap, general-purpose tag with a short URL address. | A new-generation tag, which will probably in the future replace the now very widespread NTAG203. Excellent functional distance for data transfer. | A golden mean, good memory capacity, but limited availability. | Large memory, good functional distance and other characteristics too. The higher price makes this tag suitable above all for sophisticated systems. |
| Universal compatibility (4) | Yes | Yes | Yes | Yes | Yes | Yes |
| NFC Forum compatibility (5) | Yes | Yes | Yes | Yes | Yes | Yes |
| Scan counter | No | No | No | Yes | Yes | Yes |
| 32-bit password | No | No | Yes | Yes | Yes | Yes |
| Serial number (6) | 7 bytes | 7 bytes | 7 bytes | 7 bytes | 7 bytes | 7 bytes |
| Encryption (7) | No | No | No | No | No | No |
| Functional distance (8) | Good | Good | Good | Very good | Good | Good |
| Other NFC tags | ||||
| Ultralight C | Mifare 1k | Desfire 4k | Topaz 512 | |
| Memory size (1) | 192 | 1024 | 4096 | 512 |
| (in Bytes) | ||||
| User memory (2) | 148 | 716 | 4094 | 454 |
| (in Bytes) | ||||
| URL length (3) | 132 | 710 | 2000 | 449 |
| (number of characters) | ||||
| Best use | Suitable for applications requiring encryption. Weak functional scanning distance. | Suitable only for older applications, not recommended for general use. Not compatible with all NFC phones. | Suitable for special applications that require very strong encryption. | A universally compatible tag, available only in a small number of products. Useful for business cards and small data storage. |
| Universal compatibility (4) | Yes | No | Yes | Yes |
| NFC Forum compatibility (5) | Yes | No | Yes | Yes |
| Serial number (6) | 7 bytes | 4 or 7 bytes | 7 bytes | 4 bytes |
| Encryption (7) | Yes | Yes | Yes | No |
| Functional distance (8) | Weak | Medium | Medium | Good |
Notes to the table:
1 – Memory size: This is the total memory capacity of the chip. Part of this capacity is the so-called OTP (One time programmable), part of the memory is intended for locking. The largest share is intended for writing and reading data.
2 – User memory: This is a very important piece of information for the user. It is the free memory that you can use for storing data on the tag.
3 – URL length: In general this is the maximum possible length of the URL address that can be stored in the tag, excluding the parts containing http:// or http://www.
4 – Universal compatibility: This feature means that the tag can be successfully used with all mobile phones that support NFC.
5 - NFC Forum compatibility: Means that the tag is compatible with the NFC Forum specifications.
6 – Serial number: Every tag contains a unique serial number for identification purposes (UID). Most applications require access to the information containing this number.
7 - Encryption: A security feature that can help protect the tag against unauthorised access and copying of data. It is a very advanced characteristic that requires expert knowledge and is very rarely used by ordinary users.
8 – Functional distance: Is the distance over which the transfer of data from one device to another works.
So which NFC tag to choose?
In general, if someone is unsure, we usually recommend using the NTAG203. If you use Task Launcher applications, then the NTAG203 works excellently. If you are looking for a tag that you want to embed into a functional object (wristbands, key fobs, etc.), then we can recommend the Ultralight. New-generation tags (NTAG210 and NTAG213) are currently intended above all for developers and those who will make use of their additional characteristics.
If, despite this, you are still not sure, do not hesitate to contact us, we will be glad to help you choose.