Need 100base-tx/1000BASE‑TX front end analog circuitry, if possible with explanations. I've been searching for a while already but no success. There are only bluffy peices of information. Is it circuitry still proprietary and close? Does somebody find such info?

  • \$\begingroup\$ First question: 1000Base-TX was a total commercial failure, and I've never seen it being used anywhere. You definitely don't mean 100Base-TX/1000Base-T, do you? \$\endgroup\$ Sep 21, 2020 at 7:54
  • \$\begingroup\$ then: you haven't looked very far, I'd guess. Because most of the datasheet for PHYs come with little schematics and/or a link to a full application note from their manufacturers about how to build the frontends. \$\endgroup\$ Sep 21, 2020 at 7:55
  • \$\begingroup\$ When you ask for "front end analog circuity" are you talking about the magnetics? If so, that is all described in detail in the commercial datasheets for Ethernet magnetics. \$\endgroup\$
    – Puffafish
    Sep 21, 2020 at 7:56
  • \$\begingroup\$ Yes, I think I've made a mistake, I don't know exactly know how the most prevailing standard for Gigabit Ethernet is called... So I think it is 1000Base-T. And I don't mean magnetics I mean internal circuitry of front end transceiver, so everything before ADC. \$\endgroup\$
    – Andy
    Sep 21, 2020 at 12:54

1 Answer 1


The Standards for Ethernet are pretty explicit. But they are behind a paywall. Like all standard papers. All that information is not so public, as its a fu...huge industry and a lot of people fill their pockets with it. But anybody who pays, may read it. Convenient access unfortunately comes with costs

Also there are some books around which show common Ethernet circuits, parts of the standards. Of course excerpts in the net do not show the interesting parts.

Also you may note, the standards are clever and in most cases define just Interfaces and may present an example. There is no "this is how you must do it". But physics force that e.g. most Ethernet interfaces use a transformer combined with a common mode choke.

But you may find that industrial ethernet interface are much more hardened compared to the commercial stuff...

Buy the way, the internet is full of many examples. You may note that most are similar but have differences in the details...


  • \$\begingroup\$ "The standards just define interfaces" is important to know. The standards don't say how you must make the circuit, so it's up to you. Other companies took lots of time to figure out how to meet them, and so must you. \$\endgroup\$
    – user253751
    Sep 21, 2020 at 11:26
  • \$\begingroup\$ Thank you for the answer! I want to point that I don't mean external magnetic cuircuitry, I mean internal transeiver which is inside the IC. Maybe on ResearchGate there is something at least not very expensive? \$\endgroup\$
    – Andy
    Sep 21, 2020 at 13:01
  • \$\begingroup\$ inside a Phy... that's a huge pile of stuff. there are clock recovery circuts, phase detectors, equalizers, echo cancellation, other/all kinds of digital filters, of course manchaster encoder/decoder, 8b10b encoder/decoder,... you need a serve understanding of digital signal processing and digital communication theory. But at least 10/100MBit/s Ethernet is still not Rocket science. \$\endgroup\$
    – schnedan
    Sep 21, 2020 at 14:07
  • \$\begingroup\$ So you do not need some ethernet specific stuff... all you need is books / lectures on digital signal processing and digital communication theory... I just googled around, this might get you in: ocw.mit.edu/courses/electrical-engineering-and-computer-science/… which is a low level introduction... \$\endgroup\$
    – schnedan
    Sep 21, 2020 at 14:24
  • \$\begingroup\$ Thank you, but as I've already said, I need something like an example of analog front-end of modern PHY - so it is only PMA transmitter and nothing else, I don't need all digital stuff that goes after (like encoders, filters etc.). I'm interested only in stuff that goes befor ADC converter. Thanks! \$\endgroup\$
    – Andy
    Sep 22, 2020 at 8:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.