Hacking Know-How at Supercon 2024: Bridging the Gap Between Analog and Digital Electronics
In the modern digital age, analog computing—once considered a dinosaur—continues to have relevance, as demonstrated by lectures such as the one given by analog mix signal design engineer, Nanik Adnani, at Supercon 2024. For those who may not be familiar, analog circuit design encompasses the creation or manipulation of continuously variable signals—a factor that is often overlooked when considering our seemingly digital world.
In reality, even the cleanest digital signals are analog by nature due to factors like substrate losses, conductors, impedance, and capacitance. The disconnect between the scale of a logic gate and the actual pin from which a signal emerges from an integrated circuit is striking, with the pin's capacity to handle current inconsistent with the logic gate's capabilities. To bridge this gap, chips employ a physical interface, or PHY, which acts as an analog interface, facilitating communication between the chip's logic and the exterior world.
According to Adnani, every digital protocol in common use—ranging from LoRa and USB to Controller Area Network (CAN)—requires some degree of analog circuits. Often, chips handling these protocols have separate analog teams designing the analog circuits, which necessitate slightly different metal layer designs. Although determining the exact function of an analog circuit from an X-ray of the chip can be challenging, detecting where they are compared to digital components is a relatively simple task.
One of the best methods for learning about analog circuits is by delving into practical application—a notion reinforced by Adnani throughout his talk. He shares an example from his own life: his grandmother's walker was modified to include RGB lighting, a water gun, and a car horn. The car horn, requiring a current of 8 amperes, necessitated a PHY to boost its voltage from the 40 milliamperes produced by the microcontroller.
Other examples from the talk include the use of PHY for data storage on a cassette by Zack Nelson, a guitar pedal designed by Adnani himself for tape out, and the analog bird circuits created by Kelly Heaton. In the realm of music, analog components also play a significant role.
So, how does one learn analog circuits in an increasingly digital world? Adnani suggests beginning with textbooks, as internet posts may sometimes inaccurately represent values crucial to analog circuitry, posing more problems than solutions. Some recommended books include "Design of Analog CMOS Circuits," "Sedra and Smith," and "The Art of Electronics."
In conclusion, while analog circuits may seem like relics of the past, they continue to play a crucial role in our digital-dominated world, particularly in facilitating the interaction between digital protocols and the physical world. For those interested in exploring this area further, Adnani encourages starting with foundational materials, engaging in practical projects, and employing simulation tools to refine designs before ultimately building something tangible.
- Tinkering with analog circuits remains essential in today's digital world, as demonstrated by the continued use of analog circuits in digital protocols, such as LoRa, USB, and Controller Area Network (CAN).
- One can learn the fundamentals of analog circuit design by starting with textbooks like "Design of Analog CMOS Circuits," "Sedra and Smith," and "The Art of Electronics."
- To bridge the gap between digital logic and physical interfaces, chips employ an analog interface named PHY, which facilitates communication between the chip's logic and the exterior world, as seen in applications ranging from modifying a walker with RGB lighting, a water gun, and a car horn to data storage on cassettes and the design of guitar pedals and analog bird circuits.
