8bits-SAR-ADC电容阵列里单位电容的确定(共1页).docx

单位电容Cu的确定*1根据噪声的角度对采样电容的下限进行界定 *8 bits ADCVRP=1.8V，VRN=0V,LSB=Vref2N=1.828=7.0310-3VSNR=10lgPsPn=20lgVs,rmsVn,rms=6.02N+1.76=6.02*8+1.76=49.92dbPs=A22=1.822=1.62W50db=10lgPsPnPn=1.6210-5WVn2=KT28/2Cu单端单位电容Cu=0.01fF*2 *Cu12KTVR222N-N/2=12KT1.8222*8-8/2=0.06fF*3量化误差法*8bit量化误差其量化误差为：为量化误差， q 为最小精度。q=1.828=7.0310-3V又有电路的噪声 KT/C 要小于量化噪声KTCq212得C1fF*