ES1: Data converter breakthroughs in retrospect

The performance of data converters has been pushed relentlessly over the years, leveraging advancements in scaling and design techniques that exploit the high density and speed of modern process technology. However, most of the underlying architectures in use today were conceived decades ago, and are nowadays regarded as fundamental in their nature. Were these architectures viewed as fundamental, potentially long lasting breakthroughs when they were first demonstrated? In this session, we bring together four pioneers of data converter design to review the invention and progression of the basic data converter architectures. Oversampling analog-to-digital and digital-to-analog conversion has become the dominant approach in high-resolution, moderate-bandwidth interfaces. In the first talk, Bruce Wooley will review the beginnings of oversampling converters and discuss the various architectural refinements that have emerged over time. Our second talk will focus on two equally important developments of the 1970s and 1980s: charge-based A/D conversion and digital self-calibration. Hae-Seung Lee will examine these inventions in retrospect and explain why these techniques remain equally valuable today. In the third talk of this session, Stephen Lewis will lead us back to the early days of high-speed pipelined conversion. While today's pipelines can easily sample at several hundred megahertz, the challenge back then was to cope with the bandwidth of video signals. Pipelining the digitization enabled the designer to extract very high speeds from CMOS transistors that were relatively slow and still getting ready for prime time. The session concludes with a presentation from Doug Mercer on high-speed digital-to-analog converters, which will review design philosophy changes that occurred in the 1990s. With the emergence of broadband data communication, new application requirements came into play, forcing many designers of high-speed DACs back to the drawing board.