– target market: high-end customers
Pro: Fastest read/write speed, light weight, and much smaller form factor compare to USB hard drive.
Con: Higher cost compare to USB key or hard drive. Slightly bigger than USB key.
– Bandwidth consideration: USB4 is 40Gb(5GB). NVMe drive is about 7450MB read and 6900MB write(take Samsung 990 pro as an example). However, USB4 bandwidth is currently highest speed interface we have for a PC except NIC. Kind of expecting read/write performance is close to 4.x GB(of course you need to deduct protocol overhead)
-Connection:
USB4(on PC side) – USB4(on USB NVMe storage) – PCIe(M.2 on USB NVMe storage) – NVMe drive(on USB NVMe storage)
-Chipset/controller :
AS Media’s ASM2464PD has both USB4(to PC) and PCIe Gen4 x4 (to NVMe) solution in single chip which is perfectly fit the need. Get a demo board from chip vendor to verify if it meets your product requirement & performance.
-Physical interface specification:
USB4(type C) support up to 40Gb
M.2(PCIe gen3 x4)
-PCB design: Get reference design and AVL from chipset vendor. Then layout the circuits in the form factor you need in order to fit into the enclosure.
-Determine NVMe vendor(Adata, Micro, Smasung, Kingston,…etc) to be installed in your external USB4 NVMe sotrage
-Mechanical enclosure: Thanking about the heat generated by NVMe drive, the enclosure must have the capability to move the heat from NVMe to the air. So you can think about aluminum material either with fan or no fan depending on thermal condition.
-Validation: Reliability, shock & vibe, thermal, functionality, performance, system/OS compatibility, USB2/3/4 compatibility, USB boot, hot plug, etc.
-Get USB4 certificate, EMI/EMC/Safety certificates