一种有源无源混合的噪声整形SAR ADC

An Active and Passive Noise Shaping SAR ADC

传统无源噪声整形SAR ADC因无源开关电容积分器有增益误差、相位误差而整形能力较弱。在无源噪声整形的基础上,文章设计了一种有源无源结合的噪声整形SAR ADC。该电路融合了低增益OTA和正反馈电路,仅增加少量功耗,基本消除了无源噪声整形模块的增益误差、相位误差。结果表明,该噪声整形10位SAR ADC的带宽为10 kHz,采样率为320 kHz,功耗仅109μW,有效位数达15.6位。在-40℃~85℃、不同工艺角下,有效位数均超过15位。

Conventional passive noise shaping SAR ADCs have poor noise-shaping ability because of the gain and phase error of passive switching capacitor integrator.On the basis of passive noise shaping,an active and passive noise shaping SAR ADC was designed in this paper,which integrated low gain OTA and positive feedback circuit,and only a small amount of power consumption was increased,while the gain and phase errors of passive noise shaping module were nearly eliminated.The results showed that the bandwidth of the noise-shaped 10-bit SAR ADC was 10 kHz,the sampling rate was 320 kHz,the power consumption was only 109μW,and the effective number of bit(ENOB)was 15.6 bit.The ENOB were more than 15 bit at-40℃~85℃and different process corners.