학술논문

A Continuous-Time Zoom ADC for Low-Power Audio Applications
Document Type
Periodical
Source
IEEE Journal of Solid-State Circuits IEEE J. Solid-State Circuits Solid-State Circuits, IEEE Journal of. 55(4):1023-1031 Apr, 2020
Subject
Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Computing and Processing
Distortion
Quantization (signal)
Linearity
Bandwidth
Capacitors
Switches
Signal to noise ratio
A/D conversion
asynchronous SAR analog to digital converter (ADC)
audio ADC
continuous-time delta–sigma
delta–sigma ADC
dynamic zoom ADC
inverter-based operational transconductance amplifier (OTA)
low-power circuits
Language
ISSN
0018-9200
1558-173X
Abstract
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, which relaxes the power dissipation of its reference and input buffers. Fabricated in a 160-nm CMOS process, the ADC occupies 0.27 mm 2 and achieves 108.1-dB peak SNR, 106.4-dB peak signal to noise and distortion ratio (SNDR), and 108.5-dB dynamic range in a 20-kHz bandwidth while consuming 618 $\mu \text{W}$ . This results in a Schreier figure of merit (FoM) of 183.6 dB.