The current trend is the use of an RJ45 connector with the LAN transformer integrated into its casing; these offer greater reliability because, being a very compact component, they allow for easier elimination of possible electromagnetic interference.

It should be noted that in addition to standard regulations, this transformer must be compatible with the PHY chip we have selected. To facilitate this task, BEL, represented by RC Microelectrónica, has published two guides indicating the RJ45 connectors with transformers they offer and which integrated circuits are compatible with them from two of the main manufacturers, BROADCOM and MARVELL.

You can access these guides through the following links:

Bel RJ45 guide with transformer for Broadcom integrated devices

Bel RJ45 guide with transformer for Marvell integrated devices