基于亚稳态检测的SAR ADC电容失配校准算法

随着工艺进程的不断推进,逐次逼近型模数转换器(SAR ADC)的电容失配对整体电路的速度和精度影响越来越大。针对SAR ADC中电容失配的问题,提出一种基于亚稳态检测的SAR ADC电容失配校准算法,在不增加模拟电路时序复杂度的情况下,有效地解决了电容失配导致的SAR ADC精度不足问题。将该算法运用于12 bit 150 MS/s SAR ADC中,模拟结果表明,有效位数(Enob)可以达到11.93 bit,无杂散动态范围(SFDR)达到92.66 dB。

SAR ADC Capacitance Mismatch Calibration Algorithm Based on Metastable Detection

As process progresses,capacitance mismatch of the successive approximation register analog-to-digital converter(SAR ADC)has an increasing impact on the speed and accuracy of the overall circuit.Aiming at the problem of capacitance mismatch in SAR ADC,which will lead to insufficient accuracy of SAR ADC,a SAR ADC capacitive mismatch calibration algorithm is proposed based on metastable detection,which can effectively solve the problem without increasing the complexity of analog circuit timing.The algorithm is applied to the 12 bit 150 MS/s SAR ADC.The simulation results show that the effective number of bits(Enob)can reach 11.93 bit and the spurious free dinamic range(SFDR)reaches 92.66 dB.