DS90UB953-Q1: Clarification on Maximum Insertion Loss Specs

Hi Mitchell,

We check the s-parameters at nominal voltage and temperature. Although these could be factors in taking those measurements, the margin that we are providing is based on what our parts can tolerate. So, it is the max allowable insertion loss or return loss that you can have on the link when you are using our parts. Whichever cable you use, its worst case s-parameter should be less than what we spec, because anything more can cause errors on the link.

Regards,
Mandeep Singh

Thanks Mandeep!

There might have been a little confusion around my original question. Let me try to clarify - the question was regarding of whether the channel requirements given by TI take into account the worst case voltage, temperature and process (silicon)?

If my customer were to design a channel to meet the requirements, will it function when the serializer & deserializers themselves are subjected to the corners of their voltage & temperature operating conditions, and simultaneously if those parts are from the process corners?

Hopefully this makes more sense.

Thanks,
Mitchell

Hi Mitchell,

Yes, absolutely. The parts themselves go through voltage/temperature/silicon variation testing, so you will be okay as long as you meet the channel spec.

Regards,
Mandeep Singh

Hi Mandeep,

Thanks for this information, this is helpful.

Can you speak to how much more link budget margin might be available at less stringent operating temps, for example, 0 to 60C instead of -40 to +85C. Is there any curve for link loss in dB vs. temp or data rate vs. temp?

Thanks,
Mitchell

Hi Mitchell,

Really can't say because the behavior/s-parameters of the cables are so unique to the type of cable, length, amount of bending in the system.. so, it's difficult to say what margin would be available as it can change depending on the cable.

Regards,
Mandeep Singh

Hi Mandeep,

I guess the question here was geared more towards the '953 and '954 specifically, rather than the cable. Maybe there is not a way provide a figure of merit without considering the cable in the system.

If there is a way to take the cable out of the equation here and look only at the '953 and '954, how much margin could my customer expect to gain back when not operating at the voltage and temperature corners for these devices?

Thanks,
Mitchell