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29 March 2020

Difference between ASIC and FPGA | ASICs vs FPGA

What is ASIC?

ASIC stands for Application-Specific Integrated Circuit. As the name implies, ASIC is application-specific. They are designed for one sole purpose and they function the same their whole operating life for uses. For example,  consider the CPU inside your phone is an ASIC. It is meant to function as a CPU for its whole life uses.

What is FPGA?

FPGA stands for Field-programmable Gate Array. It is an integrated circuit that can be filed programmed to work as per the intended design. It means that it can work as a microprocessor or as an encryption unit, or graphics card,  or even all these three at once.

ASICs Vs FPGA | Difference between ASIC and FPGA

  • ASIC is the same for FPGA. Design is specified using HDL. Such as a Verilog. VHDL etc. While in FPGA is specified generally using hardware description languages such as VHDL or Verilog.
  • ASIC is permanent circuitry. Once the application circuit is taped out into silicon. It cannot be a channel. The circuit will work the same for its complete operating life, but FPGA is a reconfigurable circuit. FPGA can be reconfigured with a different design. They can have the capability to reconfigure a part of the chip while the remaining area of the chip is still working. This feature is widely used in accelerated computing in data centers.
  • ASIC is suited for very high volume mass production, FPGA is not suited for very high volume mass production.
  • ASIC is a very high entry barrier in a team of cost, learning curve, liaising with semiconductor foundry, etc. Starting ASIC development from scratch can cost well into millions of dollars while in FPGA easier to the entry barrier. One can get started with FPGA development for as low as the USD dollar $30.
  • ASIC is much more power-efficient than FPGA. Power consumption of ASIC can be very minutely controlled and optimized while in FPGA is less energy efficient. It requires more power for the same function which ASIC can achieve at lower power. 
  • ASIC can have complete analog circuitry. For example WiFi transceiver. On the same die along with microprocessor cores. This is the advantage with FPGA analog design are not possible. FPGA may contain specific analog hardware such as PLLs, ADC, etc. They are not much flexible to create for example RF transceiver.
  • ASIC fabricated using the same process node can run at a much higher frequency than FPGA since its circuit is optimized for its specific function Compared to ASIC limited in operating frequency in FPGA. ASIC is a similar process node. The routing and configurable logic set up the timing margin in FPGA.
  • IN FPGA is limited in operating frequency compared to ASIC of similar process nodes. The routing and configurable logic eat up the timing margin in FPGAs, ASIC fabricated using the same process node can run at a much higher frequency than FPGAs since its circuit is optimized for its specific function.
  • FPGA is highly suited for application as Radar. cell phone base station etc where the current design might need to be upgraded to use a better algorithm or to a better design. In this application, the high cost of FPGA is not the deciding factor. Instead, programmability is the deciding factor. While in ASIC are definitely not suited for application areas where the design might need to be upgraded frequently or once in a while.
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