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Original question:

ONET1141 IBIS model

ONET1141L: ONET1141L Sparameter model

D.C.
Prodigy 210 points
Part Number: ONET1141L

I downloaded the S-parameter files and viewed them with a viewer. The viewer complained about "passivity" failure. Is this expected?

It appears to me that port 1 - port 2 loss is about -45dB for frequency less than 10 GHz for EQ off case. Is this expected? What do these models represent?

www.ti.com/.../sllm178

Thanks.

  • 0
    TI__Guru* 93670 points

    Greetings,

    Passivity failure may occur if device has a gain and meanwhile ADS is expecting the part to be passive(no gain). Suggestion is to disable passivity settings on ADS.

    Please disable passivity on ADS and this should take care of the incorrect -45dB loss.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 210 points

    Hi Nasser,

    Do you have a SPICE model for the output stage (OUT+ and OUT-) of ONET1141L?

    Thanks.

  • 0 in reply to D.C.
    TI__Guru* 93670 points

    Hi D.C,

    I checked and unfortunately this is not available. If it helps, we have done optical eye evaluation and we can provide you with this report. If you like to see this report, please contact your local TI office and ask them to contact me.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 210 points

    Hi Nasser,

    Thanks for your update. I tried to work with the S-parameters file in ADS, but I cannot confidently identify the input ports and output ports. It is likely that I missed some documentations on this.

    1. Can you help me identify which port is for which pin?

    2. Do you have a sample simulation file that uses this S-parameters model?

    Thanks.

  • 0 in reply to D.C.
    TI__Guru* 93670 points

    Greetings,

    I checked this s-parameter model and please note some comments below.

    1). Port order is 1-3 and 2-4. However, there is a high DC gain(~40dB). I believe this is due to the limiting amp. stage at the output. In summary maximum EQ gain is about 6dB. At DC normally there is 0dB gain. I think this s-parameter model is messed up - due to this high DC gain. On newer parts now we provide IBIS-AMI model to get around this issue but this part was developed way before we started using IBIS-AMI models.

    2). Sample simulation model is not available. Also, please note #1 comment above.

    Regards,, Nasser