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Ian_Maw's avatar
Ian_Maw
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9 months ago
Solved

Cyclone V Emulated LVDS Signal Voltages

Hi,

I am using the two 121R resistors followed by 169R in parallel, with 100R parallel termination.

I can't find any information on what signal amplitude I would see across the 169R resistor. I need the information for derating purposes.

Thanks in advance.

Ian

Programmable Logic Device

3 Replies

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor
    9 months ago

    Hi Ian,

    for an exact calculation,  you can derive output characteristic of LVDS_E3R IO standard from IBIS files. In practice, it's very easy. Just assume full VCCIO of 2.5V as differential output voltage. Respectively current through 121 ohm resistors is 8.2 mA, voltage across 169 ohm resistor and 100 ohm termination about 0.52 V.

    Regards Frank

  • ShengN_altera's avatar
    ShengN_altera
    Icon for Super Contributor rankSuper Contributor
    9 months ago

    Kindly confirm whether the suggested steps have addressed your concern?