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Original question:

DS160PR410: VOD and DC gain

DS160PR410: DS160PR410

STEVE CACKA
Prodigy 20 points
Part Number: DS160PR410

Team,

For PCIe Gen 4, where is the document or app note describing in detailed the use of VOD and GAIN, 

The only thing I see recommended in the docs is,  

"For operation in Gen 4.0 and Gen 3.0 links, the DS160PR410 transmit outputs are designed to pass the Tx Preset signaling onto the Rx for the PCIe Gen 4.0 or Gen 3.0 link to train and optimize the equalization settings.
The suggested setting for the DS160PR410 are VOD = 0 dB and DC GAIN = 0 dB. " - Which is the L2 settings for VOD and GAIN.

Question for example, if I set the VOD to L3 what exactly happens to the signal and under what condition would I set VOD to L3 ? or other L0/L1 ?

Question for example, if I set the GAIN to L3 what exactly happens to the signal and under what condition would I set GAIN to L3 ? 

Steve

  • 0
    TI__Guru* 93670 points

    Hi Steve,

    1). When you set VOD to L3 boundary outside of the eye diagram - DC level -  is increased or is at the highest. On the other hand, L0 or L1 reduces this boundary.

    2). Setting to L3 actually increases amplitude for data pattern with a long string or ones or zeros - DC content of the data pattern. High frequency clock pattern - 0101010 .. - are not affected by this VOD and GAIN settings.

    Regards,Nasser