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I'm using microstrip to route the TX and RX differential signal pairs for an SSD drive with SATA3 interface. The total etch length for each pair on PCB is less than one inch. The dielectric constant of the FR4 is 4.8, and the thickness (from signal traces to GND plane) is 5mil. Will this FR4 material support SATA3 at 6Gbps, or I need to use a different material like Rogers 4350B?

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  • \$\begingroup\$ Take a look on a SSD or HDD PCB, it seems an ordinary PCB to me. \$\endgroup\$ – Marko Buršič Jun 1 '17 at 21:07
  • \$\begingroup\$ (I can't say definitively but) I'm pretty dead certain that SATA3 will run across FR4 because the standard will be designed around cheap, mass market PCBs inside PCs. The authority behind the standard are required to produce requirements that don't kill their own market. Being suitable for FR4 is one of their requirements and not a conclusion they reach afterwards. \$\endgroup\$ – TonyM Jun 1 '17 at 21:36
  • \$\begingroup\$ Also keep in mind that FR4 is just a flame retardant rating, and makes no guarantees at all about the dielectric material. \$\endgroup\$ – WhatRoughBeast Jun 1 '17 at 21:46
  • \$\begingroup\$ An inch should be fine in virtually any pcb material \$\endgroup\$ – Andy aka Jun 1 '17 at 21:51
  • \$\begingroup\$ Considering even the JEDS204B signaling standard can be used with FR4 and that can hit 10Gbps, over sensible distances, FR4 should be quite alright for SATA3. Analog Devices has a chart somewhere of signal loss vs frequency vs distance on FR4 and it's only a dB an inch or so. I'd imagine you'd need something like 6-10dB of loss before you even have to start to think about signal path compensation. FR408 is spec'ed to 10GHz (~20Gbps), Rodgers products aren't usually needed unless you either want really high fidelity signals, to travel meters or push 20+ GHz. \$\endgroup\$ – Sam Jun 1 '17 at 22:00

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