高速CMOS闪烁型模数转换器中的误差源研究

Study of Error Sources in High-Speed CMOS Flash ADC

对高速CMOS闪烁型模数转换器中的六种误差源进行了研究。每个误差源会潜在的限制模数转换器的线性度和信噪比。这些误差源包括基准电压的非理想因素、前置放大器引入的输入有关的时间延迟、比较器的回程噪声、时钟抖动与分布特性、温度计码中的火花码、比较器的亚稳态。在每种误差源研究的基础上,给出了相应的电路解决技术,使得吉赫频率范围中等分辨率的CMOS闪烁型ADC成为现实。

Six error sources in high-speed CMOS flash ADC are investigated. Each error source may potentially limit the linearity and SNR performance of ADC. The six error sources include reference voltages nonidealities, input-dependent delay introduced by the preamplifier, kickback noise of the comparator, clock jitter and distributed nature, sparkles in thermometer code, and comparator metastability. Based on the research of each error source, possible circuit solution is presented accordingly, making GHz-frequency medium-resolution CMOS flash ADC feasible.