UC San Diego
Harmonic distortion correction in pipelined analog to digital converters
- Author(s): Panigada, Andrea
- et al.
Pipelined analog to digital converters are widely used in telecommunication systems and instrumentation systems, where wide bandwidth analog input signals need to be converted into medium to high resolution digital signals. A pipelined analog to digital converter is sensitive to distortion introduced by its residue amplifiers, because such distortion leaks into the digital output signal, thus affecting the converter resolution. To reduce distortion, high performance operational amplifiers are usually required in the first few pipeline stages, but this causes the power consumption, the area occupation and therefore the cost of the converter to increase. An alternative approach is to design low performance operational amplifiers to reduce area and power, and compensate for the distortion they introduce by calibrating the signal in the digital domain. This dissertation presents a new digital background calibration technique called Harmonic Distortion Correction, which allows the estimation and correction of the distortion introduced by residue amplifiers in pipelined analog to digital converters. Implemented in a prototype pipelined analog to digital converter together with another digital calibration technique known in literature as DAC Noise Cancellation, Harmonic Distortion Correction has been proven to facilitate low-voltage operation and to enable reductions in power consumption relative to comparable conventional state-of-the-art pipelined analog to digital converters. Chapter 1 provides a mathematical model for the analysis of the distortion introduced by residue amplifiers in pipelined analog to digital converters, outlines the theory behind the Harmonic Distortion Correction algorithm, and presents the behavioral model of an example pipelined analog to digital converter implementing such technique. Chapter 2 presents a pipelined analog to digital converter integrated circuit prototype implementing Harmonic Distortion Correction and DAC Noise Cancellation, describes the system level and circuit level design issues and solutions, and provides the prototype measurement results.