DP83TC811S-Q1: DP83TC811S-Q1 EMC issue

Hi Eric,

Which EMC specification are you testing against?

DP83TC811S passes emissions and immunity testing per OPEN Alliance IEEE 100BASE-T1 EMC Test Specifications for Transceivers version 1.0

Regards,

Hung Nguyen

Hi Hung:

    Customer test is conducted according to the EMC outline of the automobile factory, which is mainly in accordance with CISPR 25 and ISO 11452 standards.

    Now there are some problems in RE and CE tests, please help to confirm what improvement measures are available in hardware or software design?

    Thanks!

Regards!

Eric 

Hi Eric,

Were the tests done at certified EMC test facility? Or they were tested by the customer?

Can you share the test setup for these tests, if available?

Regards,

Hung Nguyen

Hi Hung:

    Customer test in EMC test facility, the scene photos as below:

    dp83tc811s-q1 is used in T-box product. The public T-box is communicate with under test T-box, for two dp83tc811s-q1 link-up. The public t-box is completely shielded by metal to prevent its interference.

Hi Eric,

It doesn't look like you are using automotive-grade cable. That could greatly impact the EMC performance.

Regards,

Hung Nguyen

Hi Hung:
   Can you help to check the RI issue again, any Suggestions?What other information should I give you？Thanks!

----  2, In the radiation interference rejection (RI) test, dp83tc811s-q1 Ethernet chip was connected with another dp83tc811s-q1 Ethernet chip through twisted pair of wires for the packet sending test. The phenomenon of packet sending test failure occurred in the frequency range of 800M~1G and 1.6G ~2G, and returned to normal after the interference was removed. 

Hi Eric,

What twisted pair cable you are using? Can you try the same test with automotive-grade cable?

Regards,

Hung Nguyen