M88MX5891 is a Compute Express Link™ (CXL™ ) Type 3 Memory eXpander Controller (MXC) used to provide high-speed, low-latency interconnect between CPU and CXL-based devices. The MXC integrates a CXL controller, a DDR controller, a RISC-V micro-processor and rich peripheral interfaces such as SMBus and I3C/I²C in a single chip. It is compliant with JEDEC DDR4/DDR5 standards and CXL 2.0/PCIe 5.0 specifications.

As the key component for memory expansion and pooling, the MXC is designed for use in add-in cards and EDSFF memory modules, which enables dramatically scaling of memory capacity and bandwidth to meet the ever-growing demand from HPC and AI applications.



  • CXL Type 3 Memory eXpander Controller
    • Integrated CXL controller, DDR controller and RISC-V micro-processor
    • On-chip PVT sensor
    • SMBus, I3C/I²C, and SPI interfaces
    • Package: 767-ball FCCSP
  • CXL Controller
    • Compliant with CXL 1.1 and CXL 2.0 RAS specifications, supporting CXL.mem and CXL.io protocols
    • Designed based on PCIe 5.0 interface, supporting up to 32 GT/s data rate (x8 lanes)
    • Rich RAS features
  • DDR Controller
    • Compliant with JEDEC DDR4/DDR5 standards
    • Support DDR4/DDR5 UDIMM/RDIMM and DRAM on-board
    • Support up to DDR4-3200 and DDR5-4800
    • Low power consumption
    • Optimized DDR I/O equalization and programmable I/O impedance


  • Add-in card or EDSFF memory module for memory expansion, memory pooling, etc.
  • AI, machine learning, cloud infrastructure, high-performance computing, etc.