Digital Calibration Algorithms for Nyquist-rate Analog to Digital Converters

Download or read book Digital Calibration Algorithms for Nyquist-rate Analog to Digital Converters written by Anup Savla and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Continuous scaling down of CMOS device sizes and an accompanied increase in device switching speeds prompts the design of mixed-signal systems with increasingly complex digital signal processing and control algorithms accompanied by simpler analog circuitry. Analog to digital converter (ADC) is an essential mixed-signal component of modern receivers, where signals sensed from the source are converted to digital for further signal processing on them. In this dissertation, calibration techniques are presented which allow ADCs to be designed with large inherent gain and offset errors. The concept of arbitrary radix multistep conversion is presented, along with algorithms that enable reduced radix conversion with digital correction in pipelined or algorithmic ADCs. Calibration techniques that account for linear and nonlinear gain error are presented and adapted to the popular 1.5 bit/stage pipeline architecture. Calibration is performed purely with digital post-processing on ADC output bits, with no changes occurring in the analog hardware. In this dissertation a WCDMA/WLAN receiver architecture is presented and specifications are derived for all its components. Concept of reconfigurable ADC design is presented, which allows speed and power consumption optimization. Reduced radix digital correction, linear and nonlinear calibration and background-calibrating queues are presented and combined in two behavioral models. The reconfigurable ADC was fabricated in AMI0.5u 3V CMOS process, and achieved 55dB dynamic range at 45MS/s, consuming 51mW power. The reconfigured calibrated ADC was simulated in TSMC 0.18u 1.8V CMOS process, and achieved 63dB dynamic range at 25MS/s, consuming 3.6mW power. Measurements of the capture card showed a 1.6bit improvement in resolution with the use of calibration algorithms.