11 Replies Latest reply on Feb 23, 2016 7:35 AM by Carlos_A

    Ethernet phy i210 transformerless

    GatewareSL Community Member

      Hi Intel community,

      we are implementing the i210 in an embedded design and are wondering if it is possible to build a transformerless ethernet connection with it. 

      We would like to connect two i210 via 1m CAT5E cable. 

      as transformerless ethernet ever been tried with the i210? 


      As far as I know, the architecture of the driver ciruitry in the phy plays a role in this. Acc to the datasheet, the i210 has voltage mode drivers, that can be set to work in Class A or Class B mode.   Maybe you can give us some more information (maybe a rough schematic) on how the analog circuitry looks like. How did you implement Class A and Class B mode with the voltage mode driver?   


      Thank you and best regards,   Stefan Lange

        • Re: Ethernet phy i210 transformerless
          AdolfoS Brown Belt

          Hello GatewareSL


          As you can see on section 12.5 of the Datasheet: I210 Datasheet . The i210-AT/IT should be used with either discrete or integrated magnetics as they impact the compliance with IEEE standards.


          Read carefully chapter 12 Design Considerations of the datasheet before implementing your solution; specially sections 12.5 Ethernet Interface, and 12.7 Power Supplies.


          If you need to implement a transformerless solution you could use the i210-AS/IS as a MAC and connect it to a transformerless external PHY module using the SGMII/SERDES interface.


          Here is the Reference Design Schematic for both technologies:


          I210-AS/IS: http://www.intel.com/content/www/us/en/ethernet-controllers/i210-is-reference-design-schematic.html


          I210-AT/IT: http://www.intel.com/content/www/xa/en/secure/intelligent-systems/privileged/gbe-i210-i211-at-schematics.html


          This link might also be useful to you: http://www.intel.com/content/www/us/en/embedded/products/networking/ethernet-controller-i210-i211-faq.html


          Best Regards,

          Adolfo Sanchez

            • Re: Ethernet phy i210 transformerless
              GatewareSL Community Member

              Hello Adolfo and community,


              I received some information from intel support:


              There is an application note "480093" on transformerless ethernet, featuring also the i210.

              I am note sure if I may post the link here.


              Also, intel support stated the following:


              "For the magnetic-less design, for I210 we recommend to use "0.47uF" for the capacitor value.


              The capacitor placement is arbitrary, but the capacitor value is critical to the success of the design. See Table 1 for recommended starting values. Deviation from these values may be necessary. In some cases, the value of the capacitor will need to change due to vendor and device PHY performance variation.


              It is recommended that system designers should layout the PCB backplane such that the differential traces match the characteristic impedance of Category 5 or 5E UTP cable, which is ~100Ω."


              It is understood that transformerless operation should be implemented on PCB connections only (not cable).


              We will implement a short cable (1m) transformerless design anyway, with a fallback option to transformer operation. I will post the results in a couple months, hopefully I wont forget. 


              Best regards,

              Stefan Lange

              Gateware Communications GmbH

                • Re: Ethernet phy i210 transformerless
                  gabriel.thomas Brown Belt

                  Hello Stefan,


                  We would like to know how is your project doing and if you could post the results, this information is very valuable for the Community.

                  Any comment will be appreciated.



                  Gabriel Thomas

                  • Re: Ethernet phy i210 transformerless
                    asiwarski Community Member

                    Hi Stefen,


                    I am doing something similar as well.  I have successfully used an Intel I210 adapter, removed the integrated RJ45, and wired directly to another CCA as a PHY to PHY type implementation (less than 12").  The final design shall be consolidated on one PCB.  Vitesse has a white paper that discusses PHY to PHY (transformerless) which has been useful.  It's pretty easy to do as the I210 is a voltage mode type versus the current mode design.


                    Please let us know how you've progressed.


                    Andy Siwarski

                    • Re: Ethernet phy i210 transformerless
                      asiwarski Community Member

                      How can I get a copy of the Intel 480093 app note?  Is there anyone from Intel who could email it to me?

                        • Re: Ethernet phy i210 transformerless
                          gabriel.thomas Brown Belt

                          Hello Andy,


                          We are going to upload this file to the EDC library. As soon as it is available we will let you know.





                          Gabriel Thomas

                            • Re: Ethernet phy i210 transformerless
                              LynnZ Brown Belt

                              Hello, Everyone.  It appears that document 480093 is not available for general distribution.  Andy, I sent your request to Tracy, the account manager who covers your geographical territory to see if she can offer any assistance.  At this time I don't have clear idea of the timing of when/if that document will be made available on the website.  Sorry for the inconvenience.  LynnZ.


                              I learned a bit more about this document.  It describes how to do a magnetic-less design with i210.  As magnetics help protect the chip it is highly recommended to avoid magnetic-less designs in order to prevent potential problems.  Hope this helps!  LynnZ