Choosing right Magnetics

[Rahul Soni]

Can anyone please tell me what is the criteria for choosing the appropriate magnetics for RJ45 connectors and How it is made up ?

 

[Rahul Soni]

Without further specifications, can we guess that "magnetics for RJ45 connectors" refers to an etnernet interface?

If so, there are different requirements for 100 and 1000 MBit/s PHYs, and partial differences between PHY types. So you better ask for the right magnetics for a specific PHY chip. It's usually specified in vendor datasheets and reference designs.

Thank you
So you are saying that the selection of proper magnetics depends only on the ethernet speed and the PHY chip? Or something else would be needed as information ?

Thanks in advance

 

[FvM]

Without further specifications, can we guess that "magnetics for RJ45 connectors" refers to an etnernet interface?

If so, there are different requirements for 100 and 1000 MBit/s PHYs, and partial differences between PHY types. So you better ask for the right magnetics for a specific PHY chip. It's usually specified in vendor datasheets and reference designs.

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Yes.

There are some additional features that may be required, e.g. PoE, increased isolation voltage (e.g. for medical applications), RJ45 with integrated magnetics versus separated transformer.

 

[Rahul Soni]

RJ45 with integrated magnetics versus separated transformer.

I guess magnetics are generally isolation transformers, am I right ? Or can we use chock coils also in place of transformer ?

 

[FvM]

Ethernet transformers have a dedicated specification and are quite cheap, it doesn't make sense to use anything else as a replacement. Of course, if you understand the requirements, you are able to make your own transformer, or decide if a component designed for a different application would be suitable. It's more likely that designers go the opposite way, use a cheap ethernet transformer for a different application.