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 Continuous-Time Zoom ADC for Audio Applications based on a High-Linearity OTA and a 4-bit SAR ADC

Analog-to-Digital Converters (ADCs) used in high fidelity audio applications require high linearity and a wide dynamic range (>100 dB). Moreover, for use in portable electronic devices such as smartphones, tablets, and hearing aids, these ADCs must also achieve high energy efficiency. This requirement of high linearity and high energy...

The Zoom ADC: An Energy Efficient ADC for High Resolution

Analog-to-digital converters (ADCs) are an indispensable part of the digital age we are living in, as they form the interface between physical reality and virtual reality. Higher ADC energy efficiency is the dominant focus of ADC design research due to the high impact of ADC energy consumption to total energy consumption of the systems they are...

A 440-μW, 109.8-dB DR, 106.5-dB SNDR Discrete-Time Zoom ADC With a 20-kHz BW

This article describes a discrete-time zoom analog-to-digital converter (ADC) intended for audio applications. It uses a coarse 5-bit SAR ADC in tandem with a fine third-order delta-sigma modulator (ΔΣM) to efficiently obtain a high dynamic range. To minimize its over-sampling ratio (OSR) and, thus, its digital power consumption, the...

A Fully-Passive Noise-Shaping SAR for use in a Zoom ADC

The ΔΣ analog-to-digital converter (ADC) is widely used in audio applications for its high resolution. However, it is less energy efficient compared to Nyquist Rate ADCs. The growing demand for portable and wearable devices poses a more stringent power-efficient requirement on the audio system, and the traditional ADCs architecture is hard to...

A CMOS Image Sensor with Thermal Sensing Capability and Column Zoom ADCs

This paper presents a CMOS image sensor (CIS) with a zoom ADC, to quantize in-pixel temperature sensors, as well as for faster readout speed of the image pixels while maintaining low quantization noise. The proposed 15 bit zoom ADC has a 4 bit Unit Capacitor Array (UCA) SAR and a 13 bit incremental 2^nd-order delta-sigma ADC (DSADC)...

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,...

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 Dynamic Zoom ADC for Instrumentation Applications

Analog to digital converters (ADCs) are critical blocks in most signal processing chains.<br/>Especially in low bandwidth applications, there exists a need to digitize signals with high resolution and accuracy, while at the same time, expending minimum energy.<br/>This thesis presents a dynamic zoom ADC for use in such applications. The zoom ADC...

A Dynamic Zoom ADC with 109-dB DR for Audio Applications

This paper presents the first dynamic zoom ADC. Intended for audio applications, it achieves 109-dB DR, 106-dB signal-to-noise ratio, and 103-dB SNDR in a 20-kHz bandwidth, while dissipating only 1.12 mW. This translates into the state-of-the-art energy efficiency as expressed by a Schreier FoM of 181.5 dB. It also achieves the state-of-the...

A 6.3 μW 20 bit Incremental Zoom-ADC with 6 ppm INL and 1 μV Offset

A 20-bit incremental ADC for battery-powered sensor applications is presented. It is based on an energy-efficient zoom ADC architecture, which employs a coarse 6-bit SAR conversion followed by a fine 15-bit ΔΣ conversion. To further improve its energy efficiency, the ADC employs integrators based on cascoded dynamic inverters for extra gain and...