This blog post explores why analog circuit design is regaining attention and playing a vital role in an era where digital technology has become commonplace.
Recently, the terms “electronic products” and “digital products” are often used interchangeably without distinction. Until the early 1990s, signals used inside electronic products were mostly analog—values that changed continuously within a certain range—rather than digital, which consists solely of 0s and 1s. However, starting in the mid-1990s, digital electronic products began to be developed one after another. By the 2000s, analog electronic products lost their competitiveness against digital products and gradually disappeared. Consequently, the need to distinguish analog electronics from digital electronics diminished, and the terms “digital electronics” and “electronics” came to be used interchangeably.
Yet, if we say analog circuit design is regaining importance today, most people would likely wonder why analog technology is needed in an era where digital electronics are ubiquitous. In reality, analog circuit design plays an essential role in modern electronics development. Particularly in fields requiring the handling of continuous signals from the real world—where digital signal processing alone has limitations—the importance of analog technology is significantly highlighted. For instance, continuous data like the human voice, touch input, and environmental changes such as temperature or humidity are often difficult to simply convert into digital signals. Processing such data necessitates analog methods that cannot be fully replaced by digital signals. So why is analog technology important in the digital age?
Let’s take the everyday example of a mobile phone. There are two ways to enter a phone number on a mobile phone. If it has a touchscreen, you press the keys displayed on the screen. If it has physical key buttons, you press the corresponding keys to enter the number. At this point, the various commands we input into the phone, including touch actions, are converted into 0s and 1s. However, our hand movements or voice commands are analog signals that change continuously. To convert and interpret these signals as digital signals, analog circuits are required. Analog circuits become the core technology that enables the precise processing of such continuous signals.
Furthermore, as modern electronic devices increasingly demand complex functionality, designs requiring a closer integration of analog and digital circuits are becoming essential. For example, when using a smartphone camera, the function of digitally storing images is handled by digital signal processing circuits. However, the initial process of converting light into electrical signals relies on analog circuits. Thus, modern electronic devices combine analog and digital technologies in many aspects.
So why has analog processing technology become particularly important? For instance, when using a touchscreen, users experience significant inconvenience if the device does not respond exactly as intended. As the technology for accurately interpreting analog signals and converting them into digital signals becomes more precise, users can issue commands to the device more naturally. This interface enables more intuitive interaction between users and electronic devices, increasing the importance of analog circuit design.
How is this analog processing technology implemented inside electronic products? Inside electronic devices, chips of various sizes and shapes are complexly arranged. These chips are mostly composed of resistors, inductors (coils), capacitors, and transistors. Resistors limit current flow to drop voltage, inductors oppose changes in current, capacitors store charge, and transistors regulate current flow based on voltage. By combining and arranging these four elements in specific ways, circuits performing particular functions are created. The process of designing these circuits is analog circuit design.
A key factor in analog circuit design is the chip’s operating speed and power consumption. Recently, the clock frequency of high-speed chips like CPUs has become particularly important, as higher clock frequencies enable more operations to be processed. Alongside this, various design approaches to reduce power consumption are being researched. For example, in mobile devices where battery consumption is critical, power efficiency becomes an even more crucial consideration in analog circuit design. As the process shrinks, meaning transistors become smaller, power consumption decreases, but manufacturing costs increase. This requires balancing various factors during the design phase.
Systems leveraging the advantages of both digital and analog signals will be increasingly demanded in the future. For instance, analog circuit design is essential for sensor processing in autonomous vehicles or signal processing in medical devices, where human sensory input must be conveyed to the device with maximum accuracy. Furthermore, for technologies like controlling devices with hand gestures or eye movements, as seen in movies, analog circuit design capable of precisely recognizing subtle human movements is indispensable.
Thus, analog technology—which converts user commands into digital signals and enables digital products to understand those commands—is growing increasingly vital alongside the advancement of digital electronics. The development of analog circuit design technology, which bridges digital devices and the real world, remains a highly anticipated field for the future.
