A continuous time sigma-delta modulator using time-domain quantizer and feedback element
This paper discusses a continuous time sigma-delta modulator architecture that uses efficient time-domain quantizer and corresponding feedback element. The time-domain quantizer takes advantage of all quantization time slots to realize multi-bit quantization. Thus, the performance is enhanced while the power consumption of the quantizer is reduced. The feedback element generates feedback pulse, and outputs to 1-bit DAC, which is inherently linear. A 20 MHz bandwidth sigma-delta modulator is designed. The evaluation indicates that the 3-order modulator achieves 75.1dB peak SNDR, 81 dB peak SNR and 82 dB DR.