DS92LV0421: Spread Spectrum clocking (SSC) input

Nao

Part Number: DS92LV0421
Other Parts Discussed in Thread: DS92LV0422, DS92LV2422

Hi, E2E menbers

Our Customer is considaring DS92LV0421.
According to the datasheet, DS92LV0421 can track spread spectrum clocking (SSC) from a host source.
Are DOUT+- signals affected by spread spectrum clocking (SSC) input?

Regards,
Nao

over 8 years ago

0 Nao over 8 years ago

Genius 4905 points

Hello,

Do you have any updates on this ?

Regards,
Nao

0 Nao over 8 years ago in reply to Nao

Genius 4905 points

Hello,

My customer is pushing me to answer about this question.
Thanks for your great support.

Regards,
Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao,

You are correct that the DS92LV0421 serializer can track spread spectrum clocking (SSC). The SSC is not cleaned up by the DS92LV0421, and therefore this is passed on to the output and will be received by the deserializer. If an SSC is provided by the host source, please ensure the SSC compatibility conditions are met for correct operation of the DS92LV0421 and the DS92LV0422. I have copied in the section from the datasheet below.

7.3.4.2.2 Serializer Spread Spectrum Compatibility
The serializer RXCLKIN is capable of tracking spread spectrum clocking (SSC) from a host source. The RXCLKIN accepts spread spectrum tracking up to 35-kHz modulation and ±0.5, ±1, or ±2% deviations (center spread). The maximum conditions for the RXCLKIN input are: a modulation frequency of 35 kHz and amplitude deviations of ±2% (4% total).

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Hi, Ryan-san

Thank you for your feedback.
I understand that SSC input is not cleaned up by the DS92LV0421.

Please let me ask some more questions.
1. Where can SSC be cleaned up in DS92LV0422?
I guess SSC is cleaned up by the clock from SSCG module in DS92LV0422.
Both clock and data outputs are modulated by SSCG clock newly, if SSCG module is enable.
Is my understanding correct?

2. Is this function same, when we use DS92LV0421 + DS92LV2422?

Regards,
Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao-san,

Please let me answer your follow-up questions below as well.:

1. Where can SSC be cleaned up in DS92LV0422?
I guess SSC is cleaned up by the clock from SSCG module in DS92LV0422.
Both clock and data outputs are modulated by SSCG clock newly, if SSCG module is enable.
Is my understanding correct?
[RH] The SSC is not cleaned up in the deserializer (DS92LV0422) either. The SSC will pass through the deserializer and be output on the data and clock outputs as well.

It is not recommended to enable SSCG on the deserializer if SSC is input to the serializer/deserializer.

2. Is this function same, when we use DS92LV0421 + DS92LV2422?
[RH] The function will be the same on both the DS92LV0422 and the DS92LV2422.

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Hi, Ryan-san

Thank you for your feedback.

I have one more question about SSC input.
You said that the SSC is not cleaned up in the deserializer (DS92LV0422).
How much are TxOUTx+-(DS92LV0422, DS92LV2422) signals affected by spread spectrum clocking (SSC) input,
if we input the following conditions? Of course, to disable SSCG on the deserializer.

=====
7.3.4.2.2 Serializer Spread Spectrum Compatibility
The serializer RXCLKIN is capable of tracking spread spectrum clocking (SSC) from a host source.
The RXCLKIN accepts spread spectrum tracking up to 35-kHz modulation and ±0.5, ±1, or ±2%
deviations (centerspread).
The maximum conditions for the RXCLKIN input are: a modulation frequency of 35 kHz and amplitude
deviations of ±2% (4% total).
=====

Regards,
Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao-san,

The TxOUT and TxClkout will have the same modulation as the SSC input to the serializer. Please adhere to the SSC Compatibility as referenced in your previous response.

7.3.4.2.2 Serializer Spread Spectrum Compatibility
The serializer RXCLKIN is capable of tracking spread spectrum clocking (SSC) from a host source.
The RXCLKIN accepts spread spectrum tracking up to 35-kHz modulation and ±0.5, ±1, or ±2%
deviations (centerspread).
The maximum conditions for the RXCLKIN input are: a modulation frequency of 35 kHz and amplitude
deviations of ±2% (4% total).

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Hi, Ryan-san

Thank you for your quick feedback.
Our customer began to evaluate connection DS92LV0422 and DS92LV2422 in earnest.
So, they have some questions about IBIS model.

1. Can DS92LV0422 and DS92LV2422 IBIS model confirm connection each other?
2. Can these model confirm function of equalizer and de-enphasis?

Regards,
Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao-san,

Please let me investigate the IBIS model for the functionality requested.

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Ryan-san

i am not familiar with IBIS model.

so, Please let me know which points do I investigate the IBIS model for the functionality requested?

Regards,

Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao-san,

I am following-up with the modeling team to determine if the current model can model the high speed data lines.

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Hi, Ryan-san

I looked into the IBIS model of DS92LV0421/2422.
DOUT+- and RIN+- are "NC (none connect)".
so, it meen that we can't confirm connection each other, right?

And then, we need to IBIS-AMI model, if confirm function of equalizer and de-enphasis, right?
Could you please share IBIS-AMI model?

Regards,
Nao

0 Ryan Hashimoto over 8 years ago in reply to Nao

TI__Intellectual 1635 points

Hi Nao-san,

You are correct that the high speed link is not currently available in the IBIS model. The IBIS-AMI has not been generated. I will investigate if we can generate the IBIS-AMI model and if we can, how long it would take. Another option is for the customer to use EVMs to test these devices.

Regards,
Ryan

0 Nao over 8 years ago in reply to Ryan Hashimoto

Genius 4905 points

Hi, Ryan-san

Thank you for your reply.
I'm waiting for your feedback about IBIS-AMI model.

Regards,
Nao

0 Nao over 8 years ago in reply to Nao

Genius 4905 points

Hi, Ryan-san

Do you have any updates on this ?

Regards,
Nao

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DS92LV0421: Spread Spectrum clocking (SSC) input