How to calculate the attenuation factor

Kailyn Chen

Hello,

As to the Figure 6 of the scaa059c.pdf application notes, so I'd like to confirm how to calculate the attenuation factor 0.68 and the Ra=23ohm?

Best regards

Kailyn

0 Ikechukwu Anyiam over 4 years ago

Hi Kailyn,

Attenuation factor is 50/(Ra+50). Attenuation factor * LVPECL output swing will give the resulting CML swing.

Regards,

I.K.

0 Kailyn Chen over 4 years ago in reply to Ikechukwu Anyiam

Hi，

Do you mean the attenuation factor is equal to CML swing/ LVPECL swing=400/750 or (750-400)/750?

But both of them are not equal to 0.68. I am sorry to interrupt you again.

Best regards

Kailyn

0 Ikechukwu Anyiam over 4 years ago in reply to Kailyn Chen

Yes. it should be CML swing / LVPECL swing. I'm not sure where the 0.68 in the app note is coming from. It may be a typo.

Regards,

I.k.

0 Kailyn Chen over 4 years ago in reply to Ikechukwu Anyiam

Hi I.K,

Thank you for your confirmation.

Best regards

Kailyn

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