针对传统无源有损积分环路滤波器相较于有源无损积分环路滤波器，具有功耗低、电路设计简单等特点，但其噪声传输函数(NTF:Noise Transfer Function)平滑，噪声整形效果较弱的问题，提出了一种无源无损的二阶积分环路滤波器，保留了无源有损积分优点的同时具有良好噪声整形效果。设计了一款分辨率为16 bit、采样率为2 Ms/s的混合架构噪声整形SARADC。仿真结果表明，在125 kHz带宽、过采样比为8时，实现了高信号与噪声失真比(SNDR(Signal to Noise and Distortion Ratio)为 91。1 dB)、高精度(14。84 bit)和低功耗(285 μW)的性能。
Noise-Shaping SAR ADC Design of High Accuracy and Low Power Consumption
The design of the loop filter in noise-shaping SAR ADC(Successive Approximation Register Analogto Digital Converter)is the key to the effect of noise shaping and is also an important module to achieve high accuracy performance.Compared with the active lossless integral loop filter,the traditional passive lossy integral loop filter has the characteristics of low power consumption and simple circuit design,but its NTF(Noise Transfer Function)is smooth and the noise shaping effect is weak.To solve this problem,a passive lossless second-order integral loop filter is proposed,which retains the advantages of the passive lossy integral loop filter and has a good noise shaping effect.A hybrid architecture noise-shaping SAR ADC with a resolution of 16 bits and a sampling rate of 2 Ms/s is also designed.The simulation results show that high SNDR(Signal to Noise and Distortion Ratio)(91.1 dB),high accuracy(14.84 bits),and low power consumption(285 μW)are achieved when the bandwidth is 125 kHz and the oversampling ratio is 8.
successive approximation register analog to digital converter(SAR ADC)noise-shaping SAR ADChigh accuracylow power consumption
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