VSD Intern - 10-bit DAC design using eSim and Sky130

Understanding the connection between the analog and digital worlds is crucial in modern electronics. The world around us operates primarily on analog signals, while digital systems are designed to process only digital signals. This necessitates the use of Analog-to-Digital Converters (ADCs) at the input of digital systems to translate real-world analog data into a format the system can understand. Conversely, Digital-to-Analog Converters (DACs) are essential for converting processed digital information back into analog signals for output.

A key component in this conversion process is the Digital-to-Analog Converter (DAC). An n-bit DAC takes an n-bit digital input and generates a corresponding analog voltage proportional to a reference voltage. A common implementation, the potentiometric DAC, utilizes a voltage divider network. In an n-bit DAC, the reference voltage (Vref, often 3.3V) is divided into 2n discrete voltage levels. This division is achieved through a series of 2n equal resistors, with switches selecting the appropriate voltage level based on the input digital word.

Designing and simulating these circuits can be simplified with open-source Electronic Design Automation (EDA) tools. eSim, formerly known as Oscad/FreeEDA, is a powerful, free and open-source EDA tool for circuit design, simulation, and PCB design. It's an integrated platform built using open-source software like KiCad, Ngspice, and GHDL. Released under the GPL license, eSim provides capabilities comparable to commercial software like OrCAD, Xpedition, and HSPICE, without the cost of licensing fees. This makes it an excellent, affordable alternative for educational institutions and small to medium-sized enterprises (SMEs). eSim is a great option for those seeking a cost-effective solution for schematic creation, circuit simulation, and PCB layout.