Smart AD and DA Conversion (Analog Circuits and Signal Processing)

The history of the application of semiconductors for controlling currents goes back all the way to 1926, in which Julius Lilienfeld led a patent for a “Method and apparatus for controlling electric currents” [1], which is considered the rst work on metal/semiconductor eld-effect transistors. More well-known is the work of William Shockley, John Bardeen and Walter Brattain in the 1940s [2, 3], after which the development of semiconductor devices commenced. In 1958, independent work from Jack Kilby and Robert Noyce ledto the invention of integrated circuits. A few milestones in IC design are the rst monolithic operational ampli er in 1963 (Fairchild?A702, Bob Widlar) and the rst o- chip 4-bit microprocessor in 1971 (Intel 4004). Ever since the start of the semiconductor history, integration plays an imp- tant role: starting from single devices, ICs with basic functions were developed (e. g. opamps, logic gates), followed by ICs that integrate larger parts of a s- tem (e. g. microprocessors, radio tuners, audio ampli ers). Following this trend of system integration, this eventually leads to the integration of analog and d- ital components in one chip, resulting in mixed-signal ICs: digital components are required because signal processing is preferably done in the digital - main; analog components are required because physical signals are analog by nature. Mixed-signal ICs are already widespread in many applications (e. g. - dio, video); for the future, it is expected that this trend will continue, leading to a larger scale of integration.

While technology evolution is beneficial for digital circuits, it can cause performance limitations for analog circuits. To benefit from the technology evolution for analog circuits as well, the smart concept aims at improving the analog performance by using digital intelligence. In Smart AD and DA Conversion, the smart concept is applied to AD and DA converters by using on-chip intelligence to detect analog imperfections and to correct for them.

First, general trends and challenges in data converter design are studied and a generalized view on smart conversion is introduced. Then, the smart concept is applied to solve specific imperfections in two design examples: a sub-binary variable-radix current-steering DA converter and a time-interleaved open-loop track&hold circuit. In both cases, the developed concepts are supported by theory and implemented test chips. The examples show that the smart concept can be successfully applied to improve the performance of AD and DA converters with respect to chip area, power consumption, static accuracy and/or dynamic accuracy.