Embedded Memory in Stratix Series FPGAs

The Stratix® family of FPGAs introduced the concept of TriMatrix memory. In TriMatrix memory, the on-chip memory is implemented in three types of different block sizes, each for a specific use. The memory type has been maintained and optimized through devices in the Stratix series.

With significant architectural changes to the internal memory in Stratix V FPGAs, we've significantly increased both the capacity and bandwidth of these structures. Stratix V FPGAs utilize two types of memory: enhanced memory logic array blocks (MLABs) and M20K memory blocks. These changes have enhanced performance and utilization, improving capabilities for digital signal processing (DSP) designs. Quartus® II software automatically migrates designs from previous Stratix series FPGA memory architectures to the new structure.
Key enhanced MLAB features improve efficiency and bandwidth:

  • Address and data registers internal to MLAB
    • Increased performance
    • Reduced logic use
  • Increased efficiency for wide, shallow FIFOs (n bits wide, 32 or 64 deep)

Key M20K memory block features enhance performance and utilization:

  • Increased embedded memory bit counts
  • Increased memory block performance
  • Improved flexibility of memory architecture to span applications
  • Simplified floorplanning and routability
  • Optional hard error correction code (ECC) protection, which can operate in pipelined or non-pipelined modes

Quartus II software selects the best-fit memory for each instantiation to provide the most efficient embedded memory implementation.

Table 1 summarizes the differences in the memory blocks and related applications between recent Stratix FPGA families.

Table 1. Comparison Between TriMatrix Blocks in Stratix III, Stratix IV, and Stratix V FPGAs

Memory Functions Stratix III/IV Stratix V
  • Processor code storage
  • Packet buffers
  • Video frame buffers
144K bits
20K bits
  • General-purpose memory
9K bits
  • Shift registers
  • Wide shallow FIFO buffers
  • Filter delay lines
640 bits
Enhanced MLAB
640 bits

For full details on memory block capacity for Stratix V devices, see the Stratix V overview page.

For details on the memory block counts for earlier Stratix FPGA families, see the relevant handbook chapters.

Table 2 summarizes the features for each of the two internal memory types implemented in Stratix V FPGAs.

Table 2. Internal Memory Features in Stratix V FPGAs

Feature MLAB M20K
Performance600 MHz600 MHz
Simple Dual-PortCheckCheck
True Dual-Port-Check
Packed Mode-Check
Low-Power ModeCheckCheck
Shift RegisterCheckCheck
Mixed ClockCheckCheck
Byte EnableCheckCheck
Address Clock EnableCheckCheck