Field-programmable gate array

The FPGA emerged from Ross Freeman's heretical idea: a chip packed with transistors organized into loosely connected logic blocks, configurable with software. At a time when engineers obsessed over using every transistor, Freeman bet that Moore's Law would make transistors cheap enough to waste. He was right, and the FPGA became one of the most important inventions in digital electronics.

The adjacent possible required both dense transistor integration and the insight that programmability trumped efficiency. Freeman and Bernard Vonderschmitt had worked at Zilog, where they saw how inflexible custom chips created bottlenecks in product development. What if hardware could be as flexible as software?

To market his invention, Freeman co-founded Xilinx in 1984. The company announced the XC2064 on November 1, 1985—the world's first field-programmable gate array. Originally called a 'Logic Cell Array,' the device contained 64 Configurable Logic Blocks (CLBs), each with two three-input lookup tables. Fabricated on a 2-micron CMOS process, it held approximately 1,000 logic gates.

The first successful test was inauspicious yet historic. Engineer Bill Carter successfully programmed an inverter—the simplest possible logic function—into one of the CLBs. He immediately called Freeman and Vonderschmitt, who were traveling in Japan, reporting that the 'DONE line had gone high.' Xilinx had created 'the world's most expensive inverter.'

But that inverter represented something revolutionary. Traditional chips required months of design, mask fabrication, and manufacturing before testing. FPGAs could be configured in seconds, tested immediately, and reconfigured if the design was wrong. Product development that once took years could happen in weeks.

The cascade transformed electronics development. FPGAs became essential for prototyping, allowing engineers to test digital designs before committing to custom chips. They enabled products too low-volume for custom silicon. They powered telecommunications equipment, medical devices, and aerospace systems where reliability mattered more than cost.

Path dependence established two FPGA dynasties. Xilinx dominated one approach; Altera, founded the same year, pursued another. Freeman tragically died of pneumonia at age 45, just five years after inventing the FPGA. But his creation thrived: IEEE listed the XC2064 as one of the '25 Microchips that Shook the World' in 2009 and inducted it into the Chip Hall of Fame in 2017. Intel acquired Altera for $16.7 billion in 2015; AMD acquired Xilinx for $50 billion in 2022. Freeman's heresy had become orthodoxy.