Can a tag be tied to a single phone?
No, not by anything the tag does. A tag answers every reader identically and has no way of recognising one phone from another. Any restriction has to be enforced by the phone, by an application, or by whatever the tag points at, and none of that stops the tag being read.
Why the tag cannot
A tag has no way of learning who is reading it. The exchange carries no identity of the reader, and the tag has no memory of previous readers.
It also has no logic. It answers the commands it receives and cannot make a decision about whether to answer.
So a tag that responds to your phone responds to every phone, in exactly the same way, and no product changes this.
Restricting at the phone
An automation on your phone recognises a particular tag and acts. Another phone reads the same tag and nothing happens, because nothing on that phone holds the rule.
This is often what people actually want, and it is why a home routine tag appears to be personal. It is worth being clear that the tag is not restricted; the behaviour simply lives elsewhere.
The content on the tag remains readable by anybody, which matters if the content itself is sensitive rather than merely inert.
Restricting at the destination
The tag opens an address, and the thing at that address decides who may proceed: a login, a session, a device it recognises.
This is the arrangement that actually restricts something, because the restriction is enforced where a decision can be made.
It also means the tag is a pointer and nothing more, which is the right shape for anything that needs access control.
Anybody can still tap it and see the login screen. Being unable to proceed is the protection, not being unable to read.
What to expect instead
Treat the tag as public, always, and put the decision at whichever end can make one.
If the requirement is that only you can use a tag, an automation on your own phone achieves it in practice and nothing on the tag is secret.
If the requirement is that only certain people may reach something, the destination has to enforce it and the tag is irrelevant to the security of it.
And if a supplier offers a tag that only works with one phone, ask which of these two they mean, because it is one of them.
Frequently asked questions
Can a chip be paired with a phone?
No. The tag learns nothing about the reader and keeps no memory of one. It answers every reader identically.
Why does my routine tag do nothing on another phone?
Because the routine is on your phone. The tag is not restricted, the behaviour simply lives elsewhere.
How do I actually restrict access?
At the destination. A login or a session can make a decision; a tag cannot.
Is the content still readable?
Always. Anybody who taps it reads what is written, whatever restriction exists elsewhere.