From the first operational amplifier IC to the present, the operational amplifier
technology has made great progress in two aspects of semiconductor manufacturing technology and circuit design. During the development of about 40 years, IC manufacturers
have used the advanced technology to design an almost "perfect" amplifier. Although the ideal amplifier is difficult to have an accurate definition, it provides an objective for the analog design engineer. The ideal amplifier should have no noise, infinite gain, infinite input impedance, zero bias current and zero offset voltage. It should not be limited by the size of the package, and does not occupy space. These are all kinds of assumptions made by many textbooks in order to get a simple transfer function.
Why are there so many choices?
In fact, choosing an amplifier is a pretty complicated thing today.
Part of the reason is that the diversity of system design requirements and the multiplicity of the circuit configuration, different amplifier products need to compromise on performance according to different application fields. The engineers who design the amplifier are constantly pushing the technology forward, and the trend will continue to evolve for the foreseeable future. At present, ADI and other manufacturing companies are combining new technology, new packaging technology and new manufacturing capabilities to create today's "perfect" amplifiers for many challenging applications. Each application is a combination of different technical indicators, so the number of amplifiers it uses will also increase to meet its requirements. Compared with the original operational amplifier, today's products extend the bandwidth and reduce the power supply voltage regulator, power consumption ,the cost and save the current PCB area. The trend will continue to grow with the increased demand for SNR and the increasing use of actual signal processing in household appliances and industrial equipment.