A 240μW 17bit ENOB ΔΣ modulator using 2nd-order noise-shaped integrating quantizer

Abstract

This paper presents a discrete-time (DT) 4^th-order ΔΣ modulator using a 2^nd-order noise-shaped integrating quantizer (NSIQ). By adding a passive finite impulse response (FIR) filter to the 1^st-order NSIQ, the proposed quantizer has obtained 2^nd-order noise shaping ability, without extra power consumption. By incorporating the digital integrator, the linearity requirement of the quantizer is relaxed. The proposed modulator is fabricated in a 0.18μm CMOS process, and operates at 1MS/s achieves a peak signal-to-noise-and-distortion ratio (SNDR) of 106.9dB in a 10kHz bandwidth while consuming 240μW with 1.8V power supply.