Both are used to implement digital logic, but they trade off flexibility against efficiency very differently.
ASIC (Application-Specific Integrated Circuit)
- Designed and manufactured for one exact task
- Very high performance and power efficiency for that task
- Extremely expensive and slow to design and manufacture — mistakes require an entirely new chip
- Makes sense for very high production volumes, where the upfront cost is spread out
FPGA (Field-Programmable Gate Array)
- Contains an array of programmable logic blocks that can be reconfigured after manufacturing
- Much faster and cheaper to prototype and iterate on
- Less power-efficient and generally slower than an equivalent ASIC
- Common for prototyping, low-volume production, and applications needing updates after deployment