A 120-MHz BW, 122-dBFS SFDR CT ΔΣ ADC With a Multi-Path Multi-Frequency Chopping Scheme

Advances in CMOS technologies and circuit techniques have led to the development of continuous-time delta-sigma modulators (CTΔ Σ Ms) that sample at gigahertz (GHz) frequencies and achieve high linearity [-100 dBc and >120 dBFS spurious-free dynamic ranges (SFDRs)] in wide bandwidths (>100 MHz). However, at low frequencies (≤ 10 MHz),...

A 590 μw, 106.6 dB SNDR, 24 kHz BW Continuous-Time Zoom ADC with a Noise-Shaping 4-bit SAR ADC

This paper presents a continuous-Time zoom ADC for audio applications. It combines a 4-bit noise-shaping coarse SAR ADC and a fine delta-sigma modulator with a tail-resistor linearized OTA for improved linearity, energy efficiency, and handling of out-of-band interferers compared to previous designs. In 160 nm CMOS, the prototype chip...

A 10 fJ·K ²Wheatstone Bridge Temperature Sensor with a Tail-Resistor-Linearized OTA

This article describes a highly energy-efficient Wheatstone bridge temperature sensor. To maximize sensitivity, the bridge is made from resistors with positive (silicided diffusion) and negative (poly) temperature coefficients. The bridge is balanced by a resistive (poly) FIR-DAC, which is part of a 2nd-order continuous-time delta-sigma...

A Continuous-Time Zoom ADC for Low-Power Audio Applications

This article presents a continuous-Time zoom analog to digital converter (ADC) for audio applications. It employs a high-speed asynchronous SAR ADC that dynamically updates the references of a continuous-Time delta-sigma modulator (CTDSM). Compared to previous switched-capacitor (SC) zoom ADCs, its input impedance is essentially resistive,...

An Energy-Efficient 3.7-nV/√ Hz Bridge Readout IC With a Stable Bridge Offset Compensation Scheme

This paper describes an energy-efficient bridge readout IC (ROIC), which consists of a capacitively coupled instrumentation amplifier (CCIA) that drives a continuous-time delta–sigma modulator (CTM). By exploiting the CCIA’s ability<br/>to block dc common-mode voltages, the bridge’s bias voltage may exceed the ROIC’s supply voltage, allowing...

A Resistor-Based Temperature Sensor With a 0.13 pJ·K² Resolution FoM

This paper describes a high-resolution energy-efficient CMOS temperature sensor, intended for the temperature compensation of MEMS/quartz frequency references. The sensor is based on silicided poly-silicon thermistors, which are embedded in a Wien-bridge RC filter. When driven at a fixed frequency, the filter exhibits a temperature-dependent...

A 0.25 mm²-Resistor-Based Temperature Sensor With an Inaccuracy of 0.12 °C (3σ) From -55 °C to 125 °C

This paper describes a compact, energy efficient, resistor-based temperature sensor that can operate over a wide temperature range (-55 °C-125 °C). The sensor is based on a Wheatstone bridge (WhB) made from silicided poly-silicon and non-silicided poly-silicon resistors. To achieve both area and energy efficiencies, the current output of the WhB...

A 4.5 nV/√Hz Capacitively Coupled Continuous-Time Sigma-Delta Modulator with an Energy-Efficient Chopping Scheme

When chopping is applied to a continuous-time sigmadelta modulator (CTΣΔM), quantization noise fold-back often occurs, leading to increased in-band noise. This can be prevented by employing a return-to-zero (RZ) digital-to-analog converter (RZ DAC) in the modulator's feedback path and arranging the chopping transitions to coincide with its RZ...

Recoding of the stop codon UGA to glycine by a BD1-5/SN-2 bacterium and niche partitioning between Alpha- and Gammaproteobacteria in a tidal sediment microbial community naturally selected in a laboratory chemostat

Sandy coastal sediments are global hotspots for microbial mineralization of organic matter and denitrification. These sediments are characterized by advective porewater flow, tidal cycling and an active and complex microbial community. Metagenomic sequencing of microbial communities sampled from such sediments showed that potential sulfur...

A 4 GHz Continuous-Time ΔΣ ADC With 70dB DR and -74dBFS THD in 125MHz BW

A 4 GHz third-order continuous-time ΔΣ ADC is presented with a loop filter topology that absorbs the pole caused by the input capacitance of its 4-bit quantizer and also compensates for the excess delay caused by the quantizer's latency. The ADC was implemented in 45 nm-LP CMOS and achieves 70 dB DR and -74 dBFS THD in a 125 MHz BW, while...

A chopper current-feedback instrumentation amplifier with a 1 mHz 1/f noise corner and an AC-coupled ripple reduction loop

This paper presents a chopper instrumentation amplifier for interfacing precision thermistor bridges. For high CMRR and DC gain, the amplifier employs a three-stage current-feedback topology with nested-Miller compensation. By chopping both the input and intermediate stages of the amplifier, a 1 mHz 1/f noise corner was achieved at an input...