低功耗高精度逐次逼近型模数转换器的设计

为解决现代数字和数模混合系统中动态模数转换器高精度、低功耗与低成本之间的矛盾，提出一种10位和200×103 /s采样数的逐次逼近式模数转换器（SAR ADC）.对电容式数模转换器电容阵列的导通时序进行了优化，在采样保持电路中加入消失调功能，在比较器设计中引入预增益级和锁存级.该模数转换器已在标准数字互补性金属氧化物半导体工艺下实现.测试结果表明，该转换器积分非线性度小于1个最低有效位(LSB)，差分非线性度小于0.5 LSB.在200 kHz采样率和191 Hz输入信号频率下信噪比为59 dB，并且在5 V供电电压下功耗为2.5 mW，芯片面积为1.3 mm2，其性能已达到ADC高线性度和低功耗的设计要求.     

Fully-Differential Multichannel Integrated Neural Signal Recording Front-End

Neural signal can be used for clinical disease diagnosis,data analysis and real-time life signal monitoring.Its analysis requires high-performance signal processors.Based on the 180 nm standard CMOS technology,a16-channel fully-differential neural recording chip is designed.The chip consists of 16-channel low-noise pre-amplifiers,a multiplexer and a successive approximation register(SAR)ADC.The result shows that the equivalent input-referred noise of recording amplifier is 3.63μV,bringing down noise efficiency factor to 4.24.At 8.5 bits effective number of bit(ENOB),the analog-to-digital converter(ADC)has an SNR of 52.6dB.The core area of the proposed neural recording front-end is about 2.46 mm~2.