DiLinKer MiniSAS HD (SFF-8643) to U.2 NVMe Cable, SFF-8639 68-Pin, 50cm, with SATA Power

A four-lane PCIe cable that takes the SFF-8643 port on your board or add-in card and turns it into a U.2 (SFF-8639) drive connector, 50 cm away, with a SATA power tail to feed the drive. It carries PCIe lanes only — the physical connector is the same one SAS uses, but the wiring inside is not, and that distinction is the whole reason this page exists.

What this cable actually does

• It moves PCIe lanes, not SAS. SFF-8643 is a shell, not a protocol. On a motherboard, a riser or a PCIe switch card the four lanes behind that shell are PCIe; on an LSI RAID card or HBA they are SAS. This assembly is wired for the first case. Plug it into the second and the drive simply never appears — no error, no warning, no drive letter.
• The SATA tail is not optional in most builds. U.2 drives draw 3.3 V, 5 V and 12 V, and a 2.5″ U.2 SSD has no other power input. The 15-pin SATA tail on this cable is what feeds it. Chassis that supply power through a U.2 backplane do not need it, which is why the connector is there but detachable.
• 50 cm is the short option. This length is for builds where the drive cage sits close to the slot: 1U and 2U chassis, M.2-to-U.2 riser cards, and tower builds with the SSD in a bay next to the board. If your routing has to travel — front cage to a rear slot, or around a full-length GPU — take the 75 cm version instead of stretching this one.
• Four lanes, straight through. Lane 0 to lane 0 and so on, no split, no re-driver, nothing to configure. A Gen3 x4 link gives you roughly 3.9 GB/s of usable bandwidth, which is the ceiling for any single U.2 drive on this cable; the drive model does not change that number.

Specifications

Compatibility

Works with

• SFF-8643 ports on a motherboard, riser card or PCIe switch card that carry PCIe lanes
• M.2-to-U.2 add-in cards that expose an SFF-8643 output
• 2.5″ U.2 NVMe SSDs (SFF-8639), any capacity or vendor
• Gen3 and Gen4 platforms — the link negotiates to whatever both ends support

Does not work with

• LSI / Broadcom RAID controllers and HBAs. Their SFF-8643 ports carry SAS lanes. A U.2 SSD will not enumerate through this cable on those cards, and we have tested it — please do not buy this for a RAID card.
• SAS or SATA drives — the 68-pin end is wired for PCIe, not for SAS signalling
• U.2 backplanes: those present a socket, so you need a cable with two SFF-8643 plugs instead
• Anything expecting a 12 Gb/s SAS link — this is not that cable

Typical deployments

• Workstation with an M.2 slot and no free PCIe slot. An M.2-to-U.2 riser converts the M.2 slot into an SFF-8643 output; this cable carries it the last 50 cm to a 2.5″ U.2 drive mounted in a bay.
• Server board with an onboard 8643 wired for NVMe. Some boards expose NVMe on SFF-8643 rather than on OCuLink or MCIO. Same cable, drive goes straight into the cage.
• Bench and test rigs. Short, light and easy to re-route when you are swapping drives all day — the 50 cm length stays out of the way on an open frame.

Frequently asked questions

Will this work with my LSI RAID card?

No. This is the single most common mistake with SFF-8643 cables, so it is worth being blunt: the connector fits, the drive does not appear. LSI RAID cards and HBAs drive SAS lanes through their 8643 ports, while a U.2 SSD needs PCIe lanes with NVMe on top. We have tested this combination and it is completely incompatible. If your card is a 94xx series Tri-Mode controller, the cable you want is our LSI94xx-specific twin-U.2 assembly instead.

Do I have to connect the SATA power tail?

Yes for a bare 2.5″ U.2 drive — it has no other power input. Leave it unplugged only when the drive is already powered by a backplane or a powered cage. The tail carries 3.3 V, 5 V and 12 V, so a standard SATA power lead from the PSU is enough.

Will it run at PCIe 4.0?

The cable is built for it and 50 cm is a comfortable length for Gen4, but the link is only as fast as the slowest part of the chain: a Gen3 slot or a Gen3 drive pins you at Gen3 speeds. Nothing breaks if the link trains one generation lower — you lose bandwidth, not the drive.

Is 50 cm long enough for my chassis?

Measure the actual path, not the straight-line distance: from the port, around the drive cage, to where the SSD sits. If the answer is over about 40 cm of real routing, take the 75 cm version — pulling a short cable tight puts load on the 68-pin connector and that is where intermittent drives come from.

Can I use two of these to reach two drives?

One cable, one drive. Each U.2 SSD needs its own four lanes and its own 68-pin connector, so two drives means two cables and two host ports. If your controller only has one 8643 port, look at a PCIe switch card or a U.2 backplane rather than trying to split this cable.

The drive powers up but is not detected — what now?

Check three things in this order: the port really carries PCIe (not SAS), the drive is seated fully in the 68-pin connector, and the SATA tail is on a live rail. If all three are fine, send us the controller or board model and the SSD model before returning anything — in our experience it is the port type far more often than the cable.

In the box

• 1 × SFF-8643 to U.2 (SFF-8639) NVMe cable, 50 cm, with SATA power tail (SKU B07JH92TD9)

Every cable is continuity- and pinout-tested before it ships and carries a 24-month warranty. If a link does not train, send us the controller model and the backplane part number before returning anything — in most cases the cable is the wrong variant for the port, not faulty, and we would rather tell you that up front.

Related

• Same cable in 75 cm, for longer chassis routing
• Need the 8643 port in the first place? M.2 to U.2 adapter
• All U.2 / NVMe cables and adapters