Fully Differential Amplifiers (FDAs) are not a specific brand but a category of amplifiers widely used in industrial and electronic applications. These amplifiers are essential in industries such as telecommunications, medical equipment, and automotive systems, where they provide high-performance signal processing with balanced differential inputs and outputs. Leading manufacturers of FDAs include Texas Instruments (USA), Analog Devices (USA), and STMicroelectronics (Switzerland). Their products, such as the THS4541 (Texas Instruments) and AD8479 (Analog Devices), are known for precision, low noise, and high-speed performance, making them ideal for data acquisition, instrumentation, and communication systems.