Microchip Technology PM8254B-F3EI

Overview

PM8254B-F3EI from Microchip is a tri-mode PCIe Gen 4 storage controller supporting NVMe, SAS-4 (24 Gbps), and SATA protocols with 8 host lanes and 8 disk lanes, 72-bit DDR4 memory interface, no hardware encryption, and 900-pin FCBGA (25 mm × 25 mm) packaging - deployed in enterprise rack servers for universal bay architectures requiring RAID 0/5 and HBA modes.

For engineers reviewing the PM8254B-F3EI datasheet, PM8254B-F3EI pinout, PM8254B-F3EI application, or PM8254B-F3EI equivalent, key selection considerations include PCIe Gen 4 x8 host interface bandwidth, SAS-4 PHY count and DCM support, DDR4 memory width, absence of on-die encryption, and compatibility with SXP 24G expanders in dense 2U server designs.

Technical Context

The PM8254B-F3EI integrates a Switchtec-based PCIe Gen 4 switch with x1–x8 bifurcation capability and supports native NVMe transparent mode alongside RAID 0/5/6/10. It implements Dynamic Channel Multiplexing (DCM) to aggregate SAS/SATA drive bandwidth over SAS-4 links.

It features 8 SAS-4 PHYs each capable of 24 Gbps, full SFF-TA-1001 tri-mode compliance, PCIe error containment (downstream port containment, poisoned TLP blocking), and 72-bit DDR4-3200 memory interface for descriptor and cache management - all within a single-die SoC architecture.

Key Specifications

Pinout & Package

PM8254B-F3EI is housed in a 900-pin Fine-Pitch Flip-Chip Ball Grid Array (FCBGA) package measuring 25 mm × 25 mm with 0.8 mm ball pitch. Pinout information is not publicly published in standalone form; full terminal mapping is defined in Microchip's SmartROC 3200 Hardware Design Guide (DS00003798B) and requires NDA-protected access for layout implementation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar tri-mode storage controller applications.

Compared with PM8255B-F3EI, the PM8254B-F3EI omits encryption logic to reduce die size and power, while versus LSI SAS9500-8i it adds NVMe support, SAS-4 speed, and DCM - making it suitable for next-gen universal-bay servers where encryption is handled externally or at host level.

Availability

PM8254B-F3EI is available at Aetrix Electronics and suitable for enterprise rack servers, high-density JBOD enclosures, cached HBA storage systems, and RAID 5 NAS appliances requiring stable component supply and long-term lifecycle support.

Supply support for PM8254B-F3EI includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog, FPGA, and storage solutions, with global design centers and manufacturing partnerships.

The SmartROC 3200 product line was designed to unify NVMe, SAS, and SATA storage connectivity in enterprise servers - delivering tri-mode flexibility, DCM-based bandwidth efficiency, and hardware RAID acceleration without compromising PCIe Gen 4 performance.

FAQ

Does PM8254B-F3EI support NVMe SSDs natively without requiring a separate PCIe switch?

Yes. The PM8254B-F3EI integrates a Switchtec-based PCIe Gen 4 switch that enables direct connection to NVMe SSDs in x1, x2, x4, or x8 configurations. It supports native NVMe transparent mode and hardware RAID for NVMe media, eliminating the need for an external PCIe switch in most topologies.

What is the maximum number of drives supported by PM8254B-F3EI in a SAS-4 configuration?

The PM8254B-F3EI provides 8 SAS-4 PHYs, each supporting up to 4 devices via SAS expanders. When paired with Microchip's SXP 24G SAS-4 expanders using DCM, it can manage up to 32 SAS/SATA drives - with bandwidth dynamically allocated per drive based on negotiated speed (6/12/24 Gbps).

Is PM8254B-F3EI pin-compatible with PM8255B-F3EI?

Yes. PM8254B-F3EI and PM8255B-F3EI share identical mechanical dimensions, thermal profile, and pinout - differing only in internal logic (encryption engine presence). This allows drop-in replacement in existing PCB layouts when upgrading to encrypted operation.

Does PM8254B-F3EI require external DDR4 memory, and what is the memory interface specification?

Yes. The PM8254B-F3EI requires external DDR4 memory connected via a 72-bit bus (64 data + 8 ECC bits) operating at 3200 MT/s. This memory stores command descriptors, RAID metadata, and caching structures - and must be implemented with matched trace lengths and controlled impedance per Microchip's Hardware Design Guide.

Can PM8254B-F3EI operate in HBA mode for all three protocols (NVMe, SAS, SATA)?

Yes. The PM8254B-F3EI supports HBA mode for NVMe (transparent passthrough), SAS (direct attached or expander-connected), and SATA (via SAS-4 PHYs). Each drive can be independently configured for HBA, RAID, or transparent mode - enabling mixed-mode backplanes in universal bay architectures.