An analog chip is a set of miniature electronic analog circuits formed in a single piece of semiconductor material. The voltage and current at specified points in the analog chip circuits vary continuously over time. By contrast, digital chips only use and create voltages or currents at discrete levels, with no intermediate values. In addition to transistors, analog chips typically have a greater number of passive elements (inductors / capacitors / resistors) than digital chips. Inductors tend to be avoided because of their large size, and a transistor and capacitor together can do the work of an inductor.
Analog chips may also contain digital logic elements to replace some analog functions or allow the chip to communicate with a microprocessor. For this reason and because the logic is commonly implemented using CMOS technology, these chips use BiCMOS processes companies like Freescale, Texas Instruments, STMicroelectronics and others. This is known as mixed signal processing and allows a designer to incorporate more functions on the chip. Some of the benefits include load protection, reduced parts count and greater reliability.
Pure analog chips in the information process have mostly been replaced by digital chips. Analog chips are high power applications and interfaces transducer being necessary for wideband signals due to the requirements of sampling rate. Research and industry in the field continues to grow and thrive. Some examples of well-known long-life analog chips are the Operational Amplifier 741 and the 555 timer.
Power supply chips are also considered analog chips. Its primary purpose is to produce a well-regulated output voltage source for other chips in the system. Since all electronic systems require electrical power, power ICs are WICPs that are important elements of such systems.