An analog integrated circuit (IC) is a basic component in most electronic devices, the most basic circuit that is a part of a larger electronic circuit. Examples of analog integrated circuits are operational amplifiers, power management circuits, and sensors; the most well-known and long-lived analog integrated circuits are the 741 operational amplifier and the 555 timer. An analog integrated circuit is what makes computers, cell phones, and digital devices work, and it can be found inside almost every consumer electronics available to mankind today. It is still used when there is a need for higher power applications and wideband signals that need sampling rate requirements, and for user interface with a transducer.
An analog integrated circuit involves an output signal that follows a continuous input signal. In the initial stage, known as the input stage, the voltage or signal is received from a source. The second stage, or the gain stage, is when amplification occurs that boosts the signal received so it can be processed more effectively. The outgoing signal is either limited or expanded in the last stage, called the output stage.
Depending on the design of the IC, the open loop voltage gain does not need to be in the upper range. These continuous signals perform functions like amplification, mixing, demodulation, and active filtering. An analog integrated circuit will be made up of semiconductors, inductors, capacitors, and resistors. For most electronic companies as well as their engineers and designers, an analog integrated circuit helps by having an available circuit on hand instead of making one. Rather than make an analog circuit from scratch, they can choose from the various options that circuit designers have already made.
This does not mean, however, that all analog integrated circuits are good enough on every electronic device. Some problems have to be resolved first before making the device. Most of these problems occur because the signal value will always change, which is more or less 20% of the original voltage or signal value. One particular problem though is that each processed semiconductor wafer is different on each electronic device.
A circuit designer can simply use a board-level design to select and test devices based on industry values. On the other hand, an analog integrated circuit will have the designer try to find that perfect balance before incorporating it to the electronic device. Currently, more circuit designs adapt mixed signal processing by which the designer replaces some analog functions with digital logic elements to allow the chip to “talk” with the microprocessor.