Mixed-signal design methodology for continuous-time quadrature bandpass ΔΣ modulator

Continuous-time (CT) quadrature bandpass (QBP) delta-sigma (ΔΣ) modulator is already in itself a mixed-signal system. That fact creates a discontinuity in the traditional IC design flow which assumes that "discrete" and "continuous" time domain designs require separate design tools. This paper presents an efficient top-down methodology for mixed-signal design. We report the design process from the system-level down to gate/transistor-level; modeling and simulation are applied to the ΔΣ modulator. We have verified the robustness and effectiveness of our approach which resulted in shorter design process cycles and higher rates of success.