DP83867 without external transformer

Sam Pan

Hi Team,

One question,

If customer application topology as below, could they get raid of the external transformer at any of the connection note?

BMC->PHY->cable->PHY->PHY-> RJ45

Thanks

Sam

over 9 years ago

0 Patrick OFarrell over 9 years ago

TI__Mastermind 31600 points

Sam,

What is the proposed application? Specifically, what length of cable is expected and what is the relationship of the boards on either end of the cable?

The TPPMD specification requires 1500Vrms for UTP isolation. In a typical application, this isolation is provided by the transformer.

Patrick

0 Sam Pan over 9 years ago in reply to Patrick OFarrell

TI__Expert 3860 points

Hi Patrick,

Below is the application topology.

So adding transformer is necessary due to the isolation requirement right?

And another question, if we connect three TI DP83867 together, do we still have to connect MDIO and MDC of the RGMII for all DP83867 or just connect it for 1 or 2 DP83867?

Thanks!

Sam

0 Patrick OFarrell over 9 years ago in reply to Sam Pan

TI__Mastermind 31600 points

Sam,

Yes, I would still recommend a transformer. I would also recommend connecting MDC/MDIO to each DP83867.

Patrick

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DP83867 without external transformer