Studies on Design Automation of Analog Circuits : the Design Flow

Abstract: During the past few years the concept of system-on-chip (SoC) have become an important segment in the market of integrated circuits. This recent development have increased not only the number of devices and the functionality that can be put on a chip, but the chips now includes both digital and analog circuits.ln digital design the level of abstraction and automation in the design flow have manage to keep in phase with this development. However, this is not the case for analog circuits. The analog design flow suffers from a low-level of abstraction and automation, making it one of the major bottlenecks in mixed signal design.Here we address the problem of automating the analog design now. Specifically, the problem of determining the design parameters for an analog integrated circuit at the cell level is considered. An optimization method in conjunction with automatically derived equations for the circuit performance is used to solve this task. The methods and algorithms used have been implemented into a tool that can be used to design continuous-time analog amplifiers. Using this approach the design time can be reduced from weeks to hours, at the same time the circuit performance can potentially be increased.The coupling between the device sizing and layout generation is also addressed. A parasitic feedback approach is used in order to make sure that the performance requirements are met for the circuit layout.The tool is also used to explore the design space in analog amplifier design and find trade-offs. An example where three different amplifier topologies are compared is given. It shows that large savings can be made, with respect to both area and power consumption, by selecting the best topology to meet a specific performance specification.