A variety of systems and components are designed to run using either digital or analog circuits, but there is also the need for a circuit to be able to work using both digital and analog. This is called a mixed-signal integrated circuit and requires specialized mixed signal design considerations.
In essence, a mixed-signal integrated circuit is often used as a component that allows an analog signal from another component to be converted into a digital signal for subsequent components in the design to read and process. This conversion of one signal to the other is essential in the design and has to be completely accurate to allow precise reading of the input by the digital components.
Examples to Consider
A very common and easy to conceptualize need for mixed signal design is in radios and media players. The input is in analog form and then the mixed-signal integrated circuit converts that input to digital signals which can be read by the digital amplifiers to create the sound heard from the speakers.
Alternatively, and perhaps even more common, is the need for mixed signal design in cell phones. In these types of devices, the mixed-signal integrated circuit is part of the SoC or system-on-chip technology. This allows all mixed-signal processing to be completed in one tiny chip, saving space and decreasing the risk of errors with multiple components involved.
Of course, these SoC components are actually doing a lot more than just converting signals, and they can actually even run operating systems, further decreasing the size of handheld devices and electronics. As portable and mobile electronics become more commonplace, the need for mixed signal design in a much wider variety of components and applications is driving the demand for production of smaller and more powerful options.
Issues to Consider
Working with mixed signal design is more complicated and problematic than working exclusively with a digital or an analog signal. One issue that can be troublesome is the need to provide power to both the analog and digital components of the chip, which are actually very different.
Keep in mind that analog signals are very basic, which is very different than the technology capable with the digital signal. Mixed signal design with both in mind in the compact chip requires a complete understanding of the appropriate theory as well as the ability to work through potential challenges in design.
