DVD 표준용 24비트 데이터 변환기

Abstract

High performance delta-sigma modulator is developed for digital audio equipment such as DVD recording systems. It employs a fifth-order single-loop 9-level delta-sigma modulator with an input-feedforward architecture. A second-order tree-structured mismatch-shaping circuit is utilized to remove tones and nonlinearities caused by capacitor mismatch of the feedback digital-to-analog converter. The modulator is designed with fully-differential switched capacitor integrators. All stages employ a class-AB OTA. The designed delta-sigma modulator when clocked at 6.4㎒ achieves 105㏈ signal-to-noise ratio(SNR) over the 20-㎑ audio band. This modulator consumes 13㎽ from a single 2.5V supply.