Innocard SFF-8674 1x2 PCIe 4.0 to U.2 dual port adapter with Hot Swap Power

Connection and conversion

This Innocard adapter converts a single SFF-8674 1x2 external Mini SAS HD connection into two U.2 SFF-8639 ports. It enables the attachment of dual U.2 NVMe SSDs to a host system via a PCIe 4.0 4X link. The design targets builders integrating high-density U.2 storage into servers or workstations where a native U.2 backplane is absent.

Sustained data handling

The adapter maintains a PCIe 4.0 4X electrical path to each U.2 port without an onboard bridge or switch, so bandwidth scales with the attached drives. Hot-plug capability is managed by an integrated SMBus 2-wire bus buffer and CLKREQ#, WAKE#, and PWRDIS signal buffers. Programmable current limits of 6.5A on the 12V rails and dedicated 3.3V load switches protect each port during insertion or removal under sustained transfer loads.

Power protection and indicators

Each U.2 port receives independent 12V hot-plug power circuitry with eFuse protection, thermal shutdown, and fault alert functions using back-to-back FET operation. Green LEDs signal power-ready status while red LEDs indicate drive activity and inverted PERST#, WAKE#, and CLKREQ# states. The 3.3V auxiliary supply is similarly guarded by load-switch protection for stable low-voltage operation.