SATA Routing issue

Hi, we are customizing the TX1 carrier board and now got some problem on impedance control. The original carrier board design implements a 90 Ohm differential routing rule on all SATA signal lines. However, based on the OEM guide, it says impedance requirement should be 95 Ohm(page 28).

Now our fab house can do a 4mil/4.7mil/4mil for an 83.59 theory value(90 Ohm), or 4mil/7mil/4 mil for 95.26 (100Ohm). Is it appropriate to choose the later one? Or it doesn’t require a strict rule?

Besides, any additional circuitry needed to add (like level shifter) if we use mSATA socket instead of SATA?

Hi KitKatY,

It has +/-15% tolerance for impedance control as you can see in OEM DG, 95.26 is better. AFAIK, SATA is compatible to mSATA, you’d better to confirm that by checking their protocols.