DP83848C Magnetics

Steve Sinn

Other Parts Discussed in Thread: DP83848C

I am working on a new board design that is using a couple of DP83848C PHYs which are connected to an onboard Ethernet Switch IC. So I have a small on-board Ethernet network with no RJ45 connectors or twisted pair cabling involved. My question is whether I need magnetics between the device's TD+/- , RD+/- pins or if I can directly connect them together?

over 11 years ago

0 Patrick OFarrell over 11 years ago

TI__Mastermind 31600 points

Steve,

Could you clarify the connections for the MII (MAC interface) pins and the MDI (cable interface) pins? To which of these pins will the switch connect? If you could provide a simple block diagram, it would help me make sure I correctly understand your planned implementation.

Patrick

0 Steve Sinn over 11 years ago in reply to Patrick OFarrell

Intellectual 435 points

1016.Ethernet Architecture.pdf

Block Diagram attached. The Ethernet switch will be connected to the MDI side of the PHY. So in the block diagram, do I need to add magnetics between the DP83848C & the KSZ8895 Ethernet Switch?

0 aviad over 11 years ago in reply to Steve Sinn

TI__Intellectual 2000 points

Hi Steve,

I think a good solution would be to use Transformer less connection. using capacitors (in series, on each MDI signal line). look for the Application note TLK110 Ethernet PHY Transformerless Operation at http://www.ti.com/product/tlk110

Thanks,

Aviad

0 Steve Sinn over 11 years ago in reply to aviad

Intellectual 435 points

Aviad,

Excellent, thanks! it looks like TI has a similar Application Note for the DP83848C PHY. http://www.ti.com/lit/an/snla088a/snla088a.pdf

Steve

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DP83848C Magnetics