88SM9705A0-NNR2I000 - SATA 6Gbps 1:5 Port Multiplier | Marvell

Network-Attached Storage (NAS)

The 88SM9705A0-NNR2I000 fits NAS designs because it multiplies one 6.0 Gbps SATA host link into five device ports, allowing a compact NAS board to serve five HDDs or SSDs without a costly multi-port host controller. In a typical topology, the NAS SoC's single SATA port connects to the multiplier's host-side PHY, and five drive connectors attach to the device-side ports, each negotiating SATA 6.0/3.0/1.5 Gbps independently. The industrial temperature grade supports enclosures placed in closets, garages, or small-server rooms without climate control. The key performance consideration is shared bandwidth: aggregate throughput across all five drives is bounded by the single 6 Gbps host link, so this architecture excels in sequential-write archive, backup-target, and home/SMB NAS workloads rather than concurrent multi-stream video editing.

Set-Top Boxes and DVRs

Marvell explicitly targets the 88SM97xx series at SATA storage enclosures used in set-top boxes and DVRs, and the 88SM9705A0-NNR2I000 matches these products' needs precisely: one host SATA channel drives an internal HDD plus optional expansion, while the 6.0 Gbps link rate sustains multi-tuner recording and simultaneous playback. The port multiplier's SATA PHY technology delivers the device compatibility needed to pass the broad HDD qualification matrix demanded by operator STB programs, reducing certification risk. Because DVR designs are consumer temperature range, engineers may also evaluate the pin-identical commercial variant NNR2C000 to trim BOM cost. Design consideration: verify the chosen HDD's power-up spin-current sequencing against host-port power budgets, since five devices behind one host link share the SATA power distribution rather than the data bandwidth in this single-drive-typical application.

External Multi-Bay Storage Enclosures

Desktop multi-bay RAID and JBOD enclosures benefit from the 88SM9705A0-NNR2I000's one-to-five expansion: a single upstream cable (one SATA or eSATA port) back to the PC controls five bays, which is why port multipliers historically dominated 4-5 bay external enclosures. The 6.0 Gbps SATA PHY supports today's SSDs, and backward compatibility covers legacy 1.5/3.0 Gbps HDDs. The industrial-grade NNR2I000 tolerates the elevated ambient temperatures common inside fan-cooled or passively cooled enclosure chassis. Performance planning note: with all five bays active, aggregate bandwidth saturates near the 6 Gbps host link (roughly 600 MB/s line rate before 8b/10b encoding overhead), so RAID 5 rebuilds and multi-drive scrubbing are bandwidth-bound; enclosure firmware should expose port multiplier discipline support (PM-aware) in the host controller.

Public Cloud and Data Center Cold Storage

Marvell positions the 88SM97xx series for SATA storage used in public cloud deployments, where cost-per-terabyte matters more than peak bandwidth. The 88SM9705A0-NNR2I000 lets dense cold-storage backplanes attach five drives per host SATA channel, reducing host controller count, PCIe lane consumption, and cabling complexity per rack unit. The industrial temperature grade provides margin for data-center aisles with relaxed cooling set-points. In such designs the multiplier typically front-ends nearline HDDs running sequential streaming or archival access patterns - exactly the workload profile where a shared 6 Gbps host link is not a bottleneck. Signal integrity is the main board-level consideration: route the five device-side SATA pairs with controlled impedance, length-matched within pair, and follow the reference design guidance in the Marvell 88SM9705 functional specifications for AC-coupling capacitors.

Industrial Embedded Storage

The NNR2I000 industrial temperature grade makes this port multiplier appropriate for industrial PCs, gateways, video-recording NVRs, and test equipment that log data to multiple SATA drives in unconditioned environments. A single embedded host SATA port expands to five drives for mirrored logging arrays or long-duration surveillance retention, all at SATA 6.0 Gbps. The 84-pin 10 x 10 mm QFN suits compact embedded boards where a PCIe-to-SATA controller plus its supporting circuitry would not fit. For long-lifecycle industrial programs, note that distributor indexes (Octopart: 6 distributors; Findchips: 0 franchised listings as of 2026-10-19) show thin authorized-channel supply - secure last-time-buy or buffer stock, and validate the commercial-grade NNR2C000 as a footprint-identical contingency if industrial-grade allocation tightens.

Surveillance and Security Recording Systems

Multi-camera NVR platforms map naturally onto the 88SM9705A0-NNR2I000: recorded video streams from many IP or analog channels land on several HDDs simultaneously, and the 1:5 topology provides the retention capacity with minimal host silicon. SATA 6.0 Gbps per device port accommodates modern surveillance-class drives, while the shared 6 Gbps host link still exceeds the sustained write bandwidth of typical multi-bay surveillance write patterns (multi-drive round-robin writes rarely exceed 300-400 MB/s aggregate for standard camera counts). The industrial grade suits NVR headends installed in unventilated cabinets. Design tip: stagger drive spin-up via PM power-management commands to limit inrush current on the shared ATX or DC input, and confirm host-controller port-multiplier (FIS-based switching) support - most mainstream SATA controllers with PM-aware firmware handle the 88SM9705 transparently.