Mini-SAS HD Cable, SFF-8643 to SFF-8644

Overview

A Mini SAS HD cable that crosses SFF-8643 to SFF-8644 is the through-chassis link: internal connector on the RAID or HBA side, external connector on the drive shelf side. It is the part that gets pulled when a shelf is re-racked, and it is the part that gets blamed when a link negotiates down. We build it to your routing and length, with the lane orientation marked, because most “bad cable” faults on these links are actually a cable that was too long, too tightly bent, or fitted in the wrong orientation.

Key Specifications

Which port you have: 8643, 8644, 8087 or 8088

All four are 4-lane SAS connectors and all four are called Mini-SAS. They are not interchangeable, and the internal and external versions differ in shell, latch and shielding:

The 8643 and 8644 pair belongs to the 12 G generation; 8087 and 8088 to the 6 G generation. Mixing generations mechanically is not possible without an adapter, and electrically it lands you at the slower rate.

These are industry-standard interface definitions under the SFF specifications and the Serial Attached SCSI standard. Your assembly is built and verified to the pinout and length stated on your drawing.

Faults that get blamed on the cable

• Length. A 12 G link has a finite budget. A cable that works at 1 m can negotiate down or drop lanes at 3 m, and the symptom looks exactly like a bad connector.
• Bend radius. These are twinaxial pairs. A tight bend at the connector exit deforms the pair and costs you margin you do not have at this rate.
• Lane orientation. The connector is keyed, but a shell fitted upside down in a tight chassis is more common than it should be, and it usually shows up as one missing lane.
• Latch wear. The squeeze latch on the internal body is plastic. After enough re-seating it stops holding, and the connector backs out under its own cable weight.
• Unseated shells. A connector that is 1 mm short looks seated and passes visually.

Replacing a link on a live shelf

1. Identify both ends before you pull anything: photo the HBA side and the shelf side.
2. Note the port numbering on the shelf, so the replacement goes back into the same physical port.
3. Quiesce the shelf if the array will let you. Do not rely on hot-plug on a degrading link.
4. Route the new cable before you seat it, keeping the bend radius at the exit generous.
5. Seat the internal end first, then the external shell, and secure the external shell screws.
6. Confirm the negotiated rate in the controller utility, not just that the devices appeared.

Typical Applications for This Mini SAS HD Cable

• HBA or RAID card inside a server to an external JBOD or drive shelf
• Storage chassis internal backplane to an external expansion port
• Test benches where a shelf is moved between hosts several times a week
• Spare cables held against a shelf that has to stay in service
• OEM build programs where the routing is fixed by the chassis

How to specify your build

1. Interface on each end: 8643, 8644, or a different pair if the equipment is older.
2. Length, measured along the actual route rather than point to point.
3. Routing constraints: bend radius, tie points, door clearance.
4. Generation: 12 G, or 6 G if the equipment is earlier.
5. Latch and shell style, and whether the external end needs screws.
6. Pinout if it is not straight-through.
7. Quantity, and whether you need matched pairs for a redundant path.

Workmanship and testing

Assembly and inspection follow IPC/WHMA-A-620 Class 3 workmanship criteria under our ISO 9001 quality management system, and every unit passes 100% continuity and pinout testing before it is packed. Conductor range is 32 to 12 AWG. Differential pair construction is held to the impedance stated on your drawing, and any figure quoted for the interface itself is the industry-standard value for that generation rather than a value we invent.

Every production run can ship with RoHS and REACH declarations and the electrical report agreed at quotation; see certifications and material declarations. UL styles and other named approvals are built to drawing: we source to the style you specify and document it, rather than asserting a listing we do not hold. Termination, molding and verification happen in-house see our assembly lines in Longgang so the process that made your sample is the process that runs the order. Related reading: what instrument builds require. Tooling is quoted separately, cut in-house rather than brokered out, and owned by you.

Custom builds and ordering

Mini-SAS HD prototypes start from 1 to 50 pcs and ship in 3 working days. Series supply starts at 500 pcs and takes 14 working days after approval. Tooling not already held adds around 10 working days. Mini-SAS builds ship under your part number and labeling for OEM and ODM orders, and material certificates plus first-article reports are available.

Related storage and data assemblies

Storage work usually turns up alongside these:

• SCSI HD68 Cable Assembly, HD68 to HD68
• 2V2 / 3W3 / 5W5 Mixed-Contact D-Sub Cable
• Custom Shielded Ethernet Data Cable
• Cat6A Shielded Patch Cord
• Encoder Feedback Cable with PUR Jacket
• SMA to BNC RF Coax Patch Cable
• DB50 to DB25 DTE Serial Cable

Full range: signal and data cable assemblies.

Frequently Asked Questions