工艺-电压-温度综合稳健的亚1 V 10位SAR ADC

A Sub-1 V 10 bit SAR ADC Robust Against Process-Voltage-Temperature Variation

采用0.11-μm CMOS工艺设计了一款10位亚1 V工艺-电压-温度(Process-Voltage-Temperature,PVT)综合稳健的逐次逼近寄存器型(Successive-Approximation-Register,SAR)模数转换器(Analog-to-Digital Converter,ADC)IP核.由于SAR ADC数字化程度较高,为了降低整体功耗,采用小于标准电压的亚1 V供电.然而,对于异步SAR ADC,在低压下面临严峻的PVT不稳健问题,传统采用固定延迟电路的方式无法应对所有的PVT偏差,会导致ADC良率下降.提出一种用于异步SAR ADC的可配置延迟调控技术,采用3输入译码器调节延迟电路的电流,以满足ADC在多种PVT组合下所需的延时,在TT,SS,FF,SF,FS这5种工艺角,0.9~1 V供电范围和-40~85℃的温度范围下,均取得了良好的动态特性.在0.95 V供电,采样速率为200 kS/s时,总功耗为2.24μW,FoM值仅为16.46 fJ/Conv.-step.

A 10 bit successive-approximation-register(SAR)analog-to-digital converter(ADC)is designed by using 0.11μm CMOS technology.It can operate with sub-1 V supply voltage and is robust against process,voltage,and tempera⁃ture(PVT)variation.Since SAR ADC is with a highly digitized structure,a sub-1 V power supply which is smaller than the standard supply voltage is used for power reduction.However,asynchronous SAR ADCs are sensitive to PVT fluctua⁃tions,especially under low supply voltages.The commonly used delay circuit in asynchronous SAR ADC usually features fixed delay without any configurable function,so that the ADC cannot operate properly under all PVT conditions,leading to the degradation of ADC yield.A programmable delay-controlling technique is proposed in this paper for asynchronous SAR ADC.A 3-to-8 line decoder is used to control the adjustment of current supplied to the delay circuit,so that different delay requirements of the ADC under different PVT conditions can be satisfied.The post-layout simulation results verify its robustness against variations of process corners(TT,SS,FF,SF and FS),supply voltage from 0.9 V to 1 V,and tempera⁃ture from-40℃to 85℃.With a supply voltage of 0.95 V and a sampling rate of 200 kS/s,the power consumption of this ADC is 2.24μW,and the FoM value is only 16.46 fJ/Conv.-step.