The Zoom ADC: An Evolving Architecture

Zoom ADCs combine a coarse SAR ADC with a fine delta-sigma modulator (?SM) to efficiently obtain high energy efficiency and high dynamic range. This makes them well suited for use in various instrumentation and audio applications. However, zoom ADCs also have drawbacks. The use of over-ranging in their fine modulators may limit SNDR, large...

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 Capacitively Degenerated 100-dB Linear 20-150 MS/s Dynamic Amplifier

This paper presents a new dynamic residue amplifier topology for pipelined analog-to-digital converters. With an input signal of 100 mV_pp,diff and 4 × gain, it achieves-100-dB total harmonic distortion, the lowest ever reported for a dynamic amplifier. Compared to the state of the art, it exhibits 25 dB better linearity with twice...

A 66-dB SNDR Pipelined Split-ADC in 40-nm CMOS Using a Class-AB Residue Amplifier

This paper presents a closed-loop class-AB residue amplifier for pipelined analog-to-digital converters (ADCs). It consists of a push-pull structure with a ``split-capacitor'' biasing circuit that enhances its power efficiency. The amplifier is inherently quite linear, and so incomplete settling can be used to save power while still...

A 280 μW Dynamic Zoom ADC With 120 dB DR 118 dB SNDR in 1 kHz BW

This paper presents a dynamic zoom analog-to-digital converter for use in low-bandwidth (<1 kHz) instrumentation applications. It employs a high-speed asynchronous successive approximation register (SAR) ADC that dynamically updates the references of a fully differential Δ Σ ADC. Compared to previous zoom ADCs,...

A 280μW dynamic-zoom ADC with 120dB DR and 118dB SNDR in 1kHz BW

Micro-power ADCs with high linearity and dynamic range (DR) are required in several applications, such as smart sensors, biomedical imaging, and portable instrumentation. Since the signals of interest are then often small (tens of μν) and slow (<1kHz BW), such ADCs should also exhibit low offset and flicker noise. Noise-shaping SAR [1] and...

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 20-bit ±40-mV Range Read-Out IC With 50-nV Offset and 0.04% Gain Error for Bridge Transducers

This paper presents a 20-b read-out IC with ±40-mV full-scale range that is intended for use with bridge transducers. It consists of a current-feedback instrumentation amplifier (CFIA) followed by a switched-capacitor incremental ΔΣ ADC. The CFIA's offset and 1/ <i>f</i> noise are mitigated by chopping, while its gain accuracy and gain drift are...