Is there a minimum length for SATA cables?

I have designed SATA asic serdes circuits and do not recall issues with short cables.

However, we do test for very long and very short length test cases to ensure sufficient signal integrity at either extreme, as sometimes a timing circuit or equalizer misbehaves when the signal is too clean.

For instance the timing recovery relies on a sloped transition between 0 and 1, and if the cable is too short, then the 0-to-1 and 1-to-0 slopes are too steep, and the timing recovery can become noisy (it's a long story). This can be an issue in asic test set-ups, but hardly in real deployments.

However, 12in seems to be a ridiculously high minimum.


I searched the SATA 3.0 spec and could not find anything that would indicate there is a minimum cable length for SATA cables. I assume there isn't one.

There is a lot on the cables being too long, depending on the application and speed 1m to 2m seems to be the max length.

I would say design SATA cables as short as you want to. Seagate has made USB storage drives that have the SATA controller less than an inch or two from the controller. I don't see why they have included a minimum length on their website, it does not violate SATA specs (as far as I can tell).

I also can't think of a physical reason besides reflection that would dictate a minimum cable length, but the connectors are tightly matched so this shouldn't be much of a problem either.

Tags:

Sata

Cables