A 72.9-dB SNDR 20-MHz BW 2-2 Discrete-Time Sturdy MASH Delta-Sigma Modulator Using Source-Follower-Based Integrators

초록

This paper presents a 2-2 discrete-time sturdy multi-stage noise-shaping (SMASH) delta-sigma modulator using source-follower-based open-loop integrators. The resolution of the SMASH delta-sigma modulator is enhanced by eliminating the first-stage quantization noise from the output. Using the proposed source-follower-based open-loop integrator, the operating speed of the modulator is efficiently improved. The prototype delta-sigma modulator fabricated in a 65-nm CMOS process achieves a 75.8-dB dynamic range and 72.9-dB SNDR in a 20-MHz bandwidth. The modulator occupies an active area of 0.34 mm(2), and its total power consumption is 20.4 mW from a 1.2-V supply voltage operating at a 500-MHz clock frequency.

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