TPS23758: RJ45 with magnetic build in

Hi Ernest, 

Thanks for reaching out to us! 

1. Is there a way to connect the transformer center tap to the diode bridge?

Do you have a datasheet of this magnetic build-in RJ45? Normally you need to group PR12 and PR36 in one rectifier and group PR45 and PR78 in another rectifier. 

TPS23753AEVM-001 with transformer built-in RJ45 may help (www.ti.com/.../slvu315a.pdf

Also TPS2378EVM-105 (www.ti.com/.../slvu682.pdf is clear to see the PR12 & 36, 45 & 78 are connected to the rectifiers.

2. Also, does this solution need 2 RJ45 to implement? One for data port and another one for Ethernet power port.

PoE's PD side only needs one RJ45 port as input. Both data and power can be combined in that port (like J2 port in the picture below). The power is by DC voltage and data is in AC signal (for example, PR12 = -DC, PR36 = +DC, PR45 = +DC, PR78 = -DC), they can be spitted by a transformer. Some of PD board has the 2nd RJ45 port for the DATA communication only. 

Feel free to contact me if you have any further questions.

Best regards,

Diang

Hi Diang Xing,

Thank you so much. Please see the schematic of the magnetic built in

JACK-RJ45-HR911105A.pdf

Hi Ernest,

Thanks for your document.

You can connect P5 and P4 to the rectifier.

Best regards,

Diang