Study and analysis of coefficient mismatch in a MASH21 sigma-delta modulator

The quantization noise leakage of the first stage in a MASH21 sigma-delta modulator is analyzed.The results show that the finite DC gain of the opamp is the main reason for noise leakage,and finite GBW and SR only generate harmonic distortion.The relationship between DC gain and leakage is modeled and conclusions on design criteria are reached.As an example,a MASH21 modulator for a digital audio application is realized.This modulator, fabricated in an 0.18μm mixed signal process,achieves an SNDR of 91 dB...     

MASH21 Sigma-Delta调制器中系数失配的研究与分析

本文分析了MASH21调制器中第一级量化噪声的泄漏效应。研究结果显示,运放的有限直流增益是造成失配的最主要原因。本文通过理论分析和建模仿真得到了运放直流增益和噪声泄漏之间的关系以及电路的设计规格。通过音频MASH21调制器的设计,对上述分析结果进行了验证。该调制器基于0.18um的混合信号工艺实现,工作于1.8v的单电源电压,测试显示能够达到91dB的SNDR。     

一种新颖的可编程电压监测芯片

提出了一种新颖的可编程电压监测芯片设计。该芯片无需任何外部元件,仅对3个编程管脚采取不同的连接方式,即可实现36种不同的编程状态,一颗芯片可以覆盖1.5V到5.0V的电压范围。同时,特殊时序的采样保持电路和数字限流模块的设计使其具有极低的静态功耗。该芯片基于0.5μm的混合信号工艺实现,芯片面积为0.24mm2,仅消耗3μA静态电流。     

Sigma-Delta 调制器的建模、分析和设计

This paper introduces a new method for SC sigma–delta modulator modeling. It studies the integrator's different equivalent circuits in the integrating and sampling phases. This model uses the OP-AMP input pair's tail current (I₀) and overdrive voltage (v_on) as variables. The modulator's static and dynamic errors are analyzed. A group of optimized I₀ and v_on for maximum SNR and power × area ratio can be obtained through this model. As examples, a MASH21 modulator for digital audio and a second order modulator for RFID baseband are implemented and tested, and they can achieve 91 dB and 72 dB respectively, which verifies the modeling and design criteria.     

Sigma-delta modulator modeling analysis and design

This paper introduces a new method for SC sigma-delta modulator modeling.It studies the integrator's different equivalent circuits in the integrating and sampling phases.This model uses the OP-AMP input pair's tail current(I_0) and overdrive voltage(v_(on)) as variables.The modulator's static and dynamic errors are analyzed.A group of optimized I_0 and v_(on) for maximum SNR and power x area ratio can be obtained through this model.As examples, a MASH21 modulator for digital audio and a second order modu...