What is the Difference Between a FPGA and an ASIC?

Field Programmable Gate Arrays (FPGAs) and Application Specific Integrated Circuits (ASICs) provide different values to designers, and they must be carefully evaluated before choosing any one over the other. Information abounds that compares the two technologies. While FPGAs used to be selected for lower speed/complexity/volume designs in the past, today’s FPGAs easily push the 500MHz performance barrier. With unprecedented logic density increases and a host of other features, such as embedded processors, DSP blocks, clocking, and high-speed serial at ever lower price points, FPGAs are a compelling proposition for almost any type of design.

FPGA vs. ASIC Design Advantages

FPGA Design
Advantage Benefit
Faster time-to-market No layout, masks or other manufacturing steps are needed
No upfront non-recurring expenses (NRE) Costs typically associated with an ASIC design
Simpler design cycle Due to software that handles much of the routing, placement, and timing
More predictable project cycle Due to elimination of potential re-spins, wafer capacities, etc.
Field reprogramability A new bitstream can be uploaded remotely
ASIC Design
Advantage Benefit
Full custom capability For design since device is manufactured to design specs
Lower unit costs For very high volume designs
Smaller form factor Since device is manufactured to design specs

FPGA vs. ASIC Design Flow

The FPGA design flow eliminates the complex and time-consuming floorplanning, place and route, timing analysis, and mask / re-spin stages of the project since the design logic is already synthesized to be placed onto an already verified, characterized FPGA device. However, when needed, Xilinx provides the advanced floorplanning, hierarchical design, and timing tools to allow users to maximize performance for the most demanding designs.

FPGA vs. ASIC Design Flow Comparison

FPGA vs. ASIC Design Flow Comparison

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