A 44-mu W, 91.3-dB SNDR DT 16 Modulator With Second-Order Noise-Shaping SAR Quantizer

This article presents a single-loop third-order discrete-time delta-sigma modulator (DTDSM) with a 4-bit second-order noise shaping successive approximation register (NS SAR) quantizer. To realize an aggressive noise transfer function (NTF), a novel Finite Impulse Response (FIR) filter is embedded in the NS SAR. As employing a flipped voltage follower (FVF), which offers unity gain instead of an open loop dynamic amplifier, the proposed FIR filter is sharp and insensitive to process, voltage, and temperature (PVT) variation. Fabricated in a 65-nm 1P9M CMOS technology, the prototype DTDSM consumes 44 mu W when operating at a 1.2-V supply voltage and a sampling rate of 2.4 MS/s. It achieves a peak Schreier figure of merit (FoM) of 177.9 dB with a signal-to-noise and distortionratio (SNDR) of 91.3 dB at an oversampling ratio (OSR) of 64.

Automated summary

This article presents a single-loop third-order discrete-time delta-sigma modulator with a 4-bit second-order noise shaping successive approximation register quantizer. A novel finite impulse response filter is embedded in the noise shaping successive approximation register to achieve an aggressive noise transfer function. The prototype modulator achieves a peak Schreier figure of merit of 177.9 dB and a signal-to-noise and distortion ratio of 91.3 dB at an oversampling ratio of 64, with a power consumption of 44 μW.