Learn what is the difference between SFF-8639 and SFF-8643

What is the difference between SFF-8639 and SFF-8643?

1. SFF-8639 (now called U.2)

The SFF-8639 is a new connector design for connecting MultiLink SAS drives or PCIe drives (including hard drives and SSD drives). It was recently renamed "U.2" by the SSD Small Tool Group.

SFF-8639 is a revision of SFF-8680, which is a 29-pin 2-lane SAS drive interface. The SFF-8639 U.2 is a 68-pin drive interface connector with higher signal quality that supports 12Gb/s SAS and Gen 3 x4 PCIe or PCI Express NVMe.

The SFF-8639/U.2 connector can be integrated onto a pcb "docking backplane" for multiple drives, or onto a single drive "T-Card" adapter.

The SFF-8639 U.2 connector has a total of 6 high-speed signal paths, but the SAS and PCIe specifications can only use up to 4 lanes at any one time.

2. SFF-8643

The SFF-8643 is a new HD MiniSAS connector design for implementing HD SAS internal interconnect solutions.

The SFF-8643 is a 36-pin "High Density SAS" connector with a plastic body normally used for internal connections. A typical application is an INTERNAL SAS link between a SAS HBA and a SAS drive.

SFF-8643 complies with the new SAS 3.0 specification and supports 12Gb/s data transfer protocol.

The HD MiniSAS external counterpart of SFF-8643 is SFF-8644, which is also SAS 3.0 compatible and also supports 12Gb/s SAS data transfer speed.

Both the SFF-8643 and SFF-8644 can support up to 4 ports (4 lanes) of SAS data.