A 4 bit folding CMOS A/D converter.

摘要

Demands for high speed A/D converters are increasing rapidly intelecommunications and digital signal processing. Many new designs havebeen developed in the past ten years using new technologies andarchitectures to meet requirements. Due to technology advances, CMOShas become the dominant technology for A/D converters.This thesis describes a new 4 bit folding A/D converter employing an activeresistor interpolating ladder and a new transition point detection scheme toovercome some problems encountering in the conventional folding converterdesign. This design can be expanded to 5-6 bit accuracy with littlemodification to the transition point detection scheme. However, because ofan inherent property of the active resistor, the active resistor interpolatingladder can only be used for a 2 bit fine ADC for folding A/D converters.More research work needs to be done in order to use the active resistorinterpolating ladder in higher resolution designs.The basic 4 bit folding A/D converter is implemented on chip with externalclock generators. Test results are presented for the experimental converter.