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Vocabularix's avatar
Vocabularix
Icon for New Contributor rankNew Contributor
5 years ago

3V3 LVDS on MAX10

Hello all,

I am designing a board containing the 10M04SAU169, and I will need several LVDS channels to communicate with the same board (there will be multiple boards containing this design in the system).

The MAX10 datasheet recommends a VCCIO voltage of 2.375 V < VCCIO < 2.625 V, but as the chip is single-supply, I would love to have a single 3V3 digital supply, as the board is very space constrained.

A piece of information that gave me hope is intel's LVDS guide : on page 18 and 28, no VCCIO voltage is shown on the LVDS schematics, indicating that maybe multiple voltage levels are acceptable.

A very important precision is that I will use AC-coupling in the LVDS links.

So, here are my questions :

  1. Can I use a 3,3V VCCIO in Bank 3, when using true LVDS Rx/Tx ?
  2. Could the emulated driver do it (in the other banks) ?
  3. Are the LVDS receivers self-biaised (do I need to "make" the common mode voltage on the receiver end) ?

I haven't tried to assign the pins in Quartus with the 3,3 V VCCIO, but someone in the forum (did and it looks like Quartus let them.

I'm looking for a datarate between 10 and 100 Mbps, 10b/8b balancing included.

3 Replies

  • AminT_Intel's avatar
    AminT_Intel
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hello,

    The MAX10 datasheet recommends a VCCIO voltage of 2.375 V < VCCIO < 2.625 V, but as the chip is single-supply, I would love to have a single 3V3 digital supply, as the board is very space constrained

    The Vccio range for LVDS I/O Standard is from 2.375V to 2.625V. I will not recommend you to set it as 3.3V in this case as it can cause a permanent damage to your device.

    Can I use a 3,3V VCCIO in Bank 3, when using true LVDS Rx/Tx ?

    Yes but do not mix up more than one IO standard in a single I/O bank. True LVDS is supported only in Bank 3 for Max10 devices.

    Could the emulated driver do it (in the other banks) ?

    No

    Are the LVDS receivers self-biaised (do I need to "make" the common mode voltage on the receiver end) ?

    No, LVDS receivers in Altera® devices do not have on-chip dc-biasing resistors. If you are AC-coupling between an LVDS transmitter and an LVDS receiver in an Altera device, use an external DC-biasing network at the receiver end to achieve the required common mode input voltage (VICM).

    I hope this answer help in your FPGA design.

    Thank you and stay safe!

    • Vocabularix's avatar
      Vocabularix
      Icon for New Contributor rankNew Contributor
      5 years ago

      Thank you for your answers, I have a few more if you don't mind :

      Is there a differential standard that I could use with 3,3V VCCIO ? Would I get a better data rate using Bank 3 IOs ?

      I saw that the 10M08E144 Eval board powers its IOs with 3,3V, and uses its IOs in differential mode (100 ohms terminated). What is the "protocol" used ?

      • AminT_Intel's avatar
        AminT_Intel
        Icon for Regular Contributor rankRegular Contributor
        5 years ago

        Hello,

        There is no differential standard with that can use with 3.3 V VCCIO in Max 10. You can refer to Max 10 I/O Standard table from this link on table 4 page 9

        Thank you.