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Altera_Forum's avatar
Altera_Forum
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17 years ago

Stratix GX transceiver usage.

As described in new stratix IV device datasheet, the rate of transceiver can support data rate between 600Mbps and 8.5Gbps, I wonder what's the refrence clock frequency? and what's the resolution of data rate increment.

When using transceiver to carry 10Gbps Ethernet frames between cards in system, to consider the overhead of frame and 8B/10B encoding in PCS, more than 10Gbps data will be carried on link, so normally we consider 4 bound 3.75Gbps transceivers to carry 10Gbps Ethernet frames.

By now, there are higher speed transceivers in Stratix IV, if we can use 2 bound 8.5Gbps transceivers to carry 10Gbps Ethernet frames?

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    REFCLK range is detailed in Table 1–18. Stratix IV GX Transceiver Specification as 50-637.5MHz

    resolution of data increment is not an issue. if you need an odd data rate for instance 1234.56Mbs, you simply need to choose a REFCLK that combined with the PLL multiplication settings will give you that figure. Open up the ALTGX Megawizard and try it.

    I would not assume for your design that the transceivers will go higher than 8.5GBs. They may well do but its best to stick with what is specified.

    x4 3.750Gbs should be easily achievable.
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Thanks , RedSavina!

    The most important reason that I plan to use x2 8.5Gbps(actually, 2 times of 3.75G)transceivers to carry 10Gbps traffic is I want to use lesser transceivers.

    For example, I use StratixIV with 8 transceivers to implement 40Gbps capacity packet processor, etc. If it is reasonable that I used x2 7.5Gbps transceivers rather than x4 3.75Gbps transceivers?

    Another thinking, if I want to implement 50Gbps capacity packet processor, I use device with 16 transceivers, each group of x3 6.375Gbps transceivers will carry 10Gbps traffic, does it mean we can combine any number of transceivers(x2, x3, x4.....) to carry higher bandwidth traffic?