BAG: A designer-oriented integrated framework for the development of AMS circuit generators

Abstract

We introduce BAG, the Berkeley Analog Generator, an integrated framework for the development of generators of Analog and Mixed Signal (AMS) circuits. Such generators are parameterized design procedures that produce sized schematics and correct layouts optimized to meet a set of input specifications. BAG extends previous work by implementing interfaces to integrate all steps of the design flow into a single environment and by providing helper classes -both at the schematic and layout level -to aid the designer in developing truly parameterized and technology-independent circuit generators. This simplifies the codification of common tasks including technology characterization, schematic and testbench translation, simulator interfacing, physical verification and extraction, and parameterized layout creation for common styles of layout. We believe that this approach will foster design reuse, ease technology migration, and shorten time-to-market, while remaining close to the classical design flow to ease adoption. We have used BAG to design generators for several circuits, including a Voltage Controlled Oscillator (VCO) and a Switched-Capacitor (SC) voltage regulator in a CMOS 65nm process. We also present results from automatic migration of our designs to a 40nm process.

Automation of Analog IC Layout

“…Augmenting this purpose, extensive research is going into the development of higher-level parameterized module generators. These are able to generate entire layouts for basic analog circuits by hierarchically employing other generators and creating in-between interconnections [8,11,16].…”

“…Advances in analog layout automation have been made however in recent years in many R&D target areas, such as generator-based module approaches [8,9,[11][12][13]16]; and we have witnessed the emergence of constraint engineering to support top-down design styles [2,6,10,18,19,24].…”

PCDS: A new approach for the development of circuit generators in analog IC design

“…The integrated framework BAG [11] is a designer-oriented environment explicitly targeting the development of analog and mixed-signal circuit generators, both for circuit and layout. Helper classes assist the generator codification, which is implemented in plain Python.…”

“…Thereby, we follow a distinct paradigm [11] that encourages EDA to shift the development of new automatisms towards the development of designer-oriented tools, motivating design experts to create their own automatisms themselves. With our description scheme, design groups can easily (3) turn their specific expert knowledge into parameterized circuits with dedicated versatility, being both custom-tailored and (4) highly re-usable at the same time.…”

SWARM: A Self-Organization Approach for Layout Automation in Analog IC Design

“…Basic device PCells are even indispensable for today's prevalent style of manual layout creation, despite their petty abilities to relieve layout engineers merely from laborious drawing work. In fact, an ongoing trend towards more powerful compound module PCells, as for example seen in [23] and [24], can be observed. Being an incarnation of bottom-up automation, module PCells can create entire layouts for analog basic circuits in full-custom quality (Fig.…”