ASIC vs. FPGA: Which To Choose & Why

ASIC and FPGA are both integrated circuit technologies. ASIC stands for Application-Specific Integrated Circuit and is customized for a specific applications’ need. FPGA stands for Field Programmable Gate Array and can be programmed in the field. Silicon area use is a driving factor in production part cost.

What is ASIC?

ASIC architecture can range from a Gate Array , were predefined building blocks are selectively interconnected during layout process (lower development cost, higher unit price), to a full custom implementation where each transistor is optimized for a required function (higher development cost, lower unit price). Since an ASIC only includes the needed resources required to accomplish the design task, silicon area is optimized, making ASIC implementations the lowest cost solution in medium to high volume applications. Once the ASIC design is complete, the ASIC must then be manufactured in specialized fabrication facilities, which takes up to 12 weeks for engineering prototypes and 20 weeks for fully assembled and tested production ASIC.

What is FPGA?

FPGA is an acronym for Field Programmable Gate Array.  Similar to ASIC Gate Array architecture, an FPGA consists of predefined hardware resources.  Unlike an ASIC gate array, FPGA hardware resources can be programmed (connected or disconnected from each other) in the field with a simple programming device.  Once a digital design is completed, the Field Programmable Gate Array can be immediately programmed and deployed. However, such incredible flexibility is not free, FPGA parts have a very high production unit price as compared to an ASIC unit price.  FPGA technology is an excellent prototyping vehicle for digital logic and a perfect solution for low volume products.

ASIC Vs. FPGA: Which One Should You Choose?

Although ASIC implementations require more up front design cost and longer fabrication time than FPGA, ASIC offers a number of important advantages beyond just a lower production unit cost.  An ASIC can integrate valuable technology not available in an FPGA, including, analog functionality for signal conditioning and acquisition of sensor input, asynchronous logic for use of smaller footprint and lower system clock speed, power supply management, blocks optimized for specific function such as power supply control, low power functionality, and many other optimizations that add value to a design.

ASIC vs FPGA Comparison

ASIC – Application Specific Integrated Circuit FPGA – Field Programmable Gate Array
Low unit cost High unit cost
High development cost Low development cost
Long manufacturing cycle Short manufacturing cycle
Low power dissipation High power dissipation
Small footprint and multiple package options Large footprint and limited package options
Analog, Digital, and Mixed-Signal technology options Digital with limited Analog IP blocks