3-BIT Flash ADC using Cadence Allegro / OrCAD 24.1

Abstract

With the increasing demand for high-speed, low-power electronic devices, signal integrity (SI) has become a crucial aspect of printed circuit board (PCB) design. Analog-to-Digital Converters (ADCs) play a vital role in signal processing, system-on-chip (SoC) designs, and mixed-signal applications by converting analog signals into digital data. This report presents the design and implementation of a 3-bit flash ADC using Cadence Allegro/OrCAD 24.1, an industry-standard electronic design automation (EDA) tool. The PCB design process is explored in three major steps: schematic entry, PCB layout, and SI analysis. Design Entry CIS and Allegro AMS Simulator are used for schematic capture and circuit simulation, while Allegro PCB Editor is utilized for layout design and routing. The 3-bit flash ADC architecture, consisting of a resistor ladder, comparators, and an encoder, is analyzed for performance at varying input frequencies. Key metrics such as resolution, sampling rate, and power consumption are examined to assess functionality. The report also evaluates PCB design tools, considering essential features like multilayer design capability, footprint creation, autorouting, and 3D visualization. While Cadence Allegro provides robust design capabilities, challenges such as high cost, complex user interface, and intricate file management are discussed. This report focuses on designing and implementing a 3-bit flash Analog-to-Digital Converter (ADC) using Cadence Allegro 24.1. ADCs play a vital role in signal processing, system-on-chip (SoC) applications, and mixed-signal designs, converting analog signals into digital representations for further processing. The performance of an ADC is determined by key factors such as resolution, sampling rate, and power consumption. Given the complexity of analog circuit design and storage, digital conversion is essential for efficient processing. The report provides a step-by-step guide to PCB design, covering schematic entry, PCB layout, and signal integrity analysis using Cadence tools. Design Entry CIS 24.1 is used for schematic entry and circuit simulation, while Allegro PCB Editor facilitates layout design and trace routing. This tutorial serves as a foundational resource for learning PCB design methodologies and EDA tool utilization, offering insights into high-speed circuit development and analysis. This study serves as a practical guide for engineers, researchers, and students looking to enhance their knowledge of high-speed PCB design and ADC implementation. By leveraging modern EDA tools, optimized circuit development methodologies can be achieved for advanced electronic applications.