Field-programmable gate array

A field-programmable gate array (FPGA) is a special kind of chip that can be changed and used for many different jobs after it is made. This makes it very useful for creating new things and testing ideas, even if you only need to make a few of them. FPGAs are used in many areas, like phones, cars, airplanes, and factories, because they can work very fast and handle many tasks at once.

To tell the FPGA what to do, people use a special language called a hardware description language, like VHDL. This is similar to the language used for making other kinds of chips called application-specific integrated circuits. The parts inside an FPGA can be set up to do many different jobs, from simple tasks to more complicated ones. They can also remember information, which makes them very flexible.

FPGAs are also helpful when people are building and testing new systems. They let engineers try out different designs and see how well they work before deciding on the final plan. This saves time and helps make sure everything works well before it is finished.

History

The FPGA industry grew from technologies like programmable read-only memory and programmable logic devices. These devices could be programmed either in factories or directly by users in the field.

Altera started in 1983 and made the first reprogrammable logic device in 1984. Xilinx (now part of AMD) created the first successful field-programmable gate array in 1985. This device had special blocks that could be programmed to connect in many ways.

During the 1990s, FPGAs became more advanced and were used in many areas like telecommunications and networking. By 2013, companies like Altera, Xilinx, and Actel controlled most of the market. Today, FPGAs are also used to help with tasks like searching online and working with artificial intelligence.

Growth

The following timelines show how FPGAs have developed over time.

Gates

• 1987: 9,000 gates, Xilinx
• 1992: 600,000, Naval Surface Warfare Department
• Early 2000s: millions
• 2013: 50 million, Xilinx

Market size

• 1985: First commercial FPGA : Xilinx XC2064
• 1987: $14 million
• c. 1993: >$385 million^{[failed verification]}
• 2005: $1.9 billion
• 2010 estimates: $2.75 billion
• 2013: $5.4 billion
• 2020 estimate: $9.8 billion
• 2030 estimate: $23.34 billion

Design starts

A design start is a new custom design for implementation on an FPGA.

• 2005: 80,000
• 2008: 90,000

Design

Contemporary FPGAs have many logic gates and memory blocks to perform complex digital tasks. They can do almost any job that a fixed circuit can, with the added benefit that you can change what they do after you’ve bought them. This flexibility is useful for many different projects.

FPGAs have very fast connections that need careful timing to work properly. They also often include special features besides basic digital functions, such as tools to manage electrical signals and tiny oscillators that keep everything running in sync. Some FPGAs even have parts that can handle both digital and analog signals, acting like a whole mini-computer on one chip.

The most common FPGA design uses a grid of logic blocks called configurable logic blocks, along with special connections and input/output points. These blocks can be linked together in many ways to create different functions.

Modern FPGAs often include ready-made functions built directly into the chip, such as math tools, memory spaces, and even small processors. These built-in features work faster and use less space than if they were made from basic logic blocks.

Many FPGAs can be updated while they are running, allowing them to change how they work depending on the task. New technologies are also combining FPGAs with traditional microprocessors to create powerful hybrid chips.

Most of the work inside an FPGA follows a steady rhythm, driven by a clock signal. FPGAs have special pathways for these clock signals to keep everything timed just right. Some FPGAs can even create new clock signals or adjust existing ones to fit complex needs.

To make FPGAs smaller and more efficient, some companies stack multiple layers of components together in one package, allowing different parts to be built using the best suited technology for their purpose.

Programming

To make an FPGA work, a designer creates a plan using special computer languages called hardware description languages or drawings called schematics. These languages help describe big ideas without drawing every tiny part by hand.

Special computer programs then turn these plans into instructions for the FPGA. Designers check these instructions to make sure they work right. Once everything looks good, the final set of instructions is sent to the FPGA to make it do what it’s supposed to do. Two common languages for this are VHDL and Verilog. There are also ready-made pieces of designs called intellectual property (IP) cores, which can save time when building big projects.

Most FPGAs use a type of memory called SRAM to hold their instructions, needing help from other memory devices to start up. Some older FPGAs used different memory types, but these are not used much anymore.

Manufacturers

In 2016, two big companies, Xilinx (now part of AMD) and Altera, were the leaders in making these special computer chips called FPGAs. Together, they controlled almost 90 percent of the market.

These companies also make special software tools for engineers to design and test their chip creations on computers like Windows and Linux. Over the years, these companies changed hands — Intel bought Altera in 2015, and AMD bought Xilinx in 2022. But in 2024, Altera became independent again. Other companies also make FPGAs, each with their own special features and uses.

Applications

FPGAs can be used to solve many different problems that computers can handle. They can even act like small computers themselves, such as the Xilinx MicroBlaze or Altera Nios II. One big advantage of FPGAs is that they can do some jobs much faster because they can work on many things at once.

FPGAs were first made to help connect parts inside computers. As they got bigger and faster, they started doing more jobs, like tasks usually done by special computers called digital signal processors. Today, FPGAs are used in important areas like medical imaging, where they help process pictures quickly.

FPGAs are also used to make certain parts of a computer program work faster. For example, the search engine Bing used FPGAs to speed up its searches. They are also helping with new technologies like artificial intelligence.

FPGAs are useful in many places, such as in space systems that can handle radiation, for keeping information safe, in fast financial trading, and even in projects that bring old computers back to life.

Usage by the United States military

FPGAs are very important for modern military communication systems. They are used in equipment like the Joint Tactical Radio System and by companies such as Thales and Harris Corporation. Their flexibility helps the military create secure and adaptable communication systems.

Security

FPGAs have both good and bad points when it comes to keeping them safe. Because FPGAs can be changed, it is harder for someone to change them secretly during making. In the past, some FPGAs showed their design when they started up, but now companies that make FPGAs have ways to keep this safe, like using special codes to protect the design.

Some FPGAs keep their settings inside and do not need extra protection. There are also special FPGAs that can only be set once, which makes them even safer.

In 2012, some researchers found that certain FPGAs had a secret problem that could let someone change important settings. In 2020, another problem was found in some FPGAs that made their protection not work at all. The company that made them did not fix this problem with new hardware for all their products.

Similar technologies

FPGAs used to be slower and used more energy than fixed circuits, but they have special benefits. One big plus is that you can change how an FPGA works after you buy it, which helps fix problems or make improvements. Some FPGAs can even change just one part while the rest keeps working.

FPGAs can also help products get to customers faster and save money on design costs. Companies sometimes use FPGAs to test their ideas before making final products.

The main difference between FPGAs and another type of device called CPLDs is how they are built. CPLDs have a simpler design that makes them easier to plan for, while FPGAs are more flexible but need more complex planning tools. FPGAs are also usually bigger and can include more advanced features like memory and math functions. CPLDs save their settings in a special type of memory that works right away, while FPGAs need help from another part to remember their settings when turned off. Sometimes both types are used together in one product, with CPLDs handling simpler tasks.