摘要
文章设计了一款Flash-SAR混合型模数转换器(analog-to-digital converter,ADC),结合了快闪型(flash)ADC与逐次逼近型(successive approximation register,SAR)ADC的优点,具有高速、高精度和低功耗的特点;提出了一种带冗余位数字校准算法,该算法在SAR ADC中添加1 bit冗余位,当第1级Flash ADC带来的误差小于一定的失调电压限度,第2级SAR ADC中的数字校正电路能够将误差校准回来,最终得到正确的数字输出。该ADC采用"3+10"的2级流水线结构,在SMIC 0.18μm互补金属氧化物半导体(complementary metal-oxide-semiconductor,CMOS)混合信号工艺下进行仿真,当电源电压为1.8 V,采样频率为100 MHz,输入信号接近Nyquist频率时,通过数字校准,ADC有效位(effective number of bits,ENOB)为10.990,信噪比为67.973 dB,无杂散波动态范围为95.381 dB,仿真结果证明了该算法能够有效提升ADC系统性能。
This paper designs a hybrid flash successive approximation register analog-to-digital converter(Flash-SAR ADC), which combines the advantages of both Flash ADC and SAR ADC, such as high speed, high accuracy and low consumption. And a digital calibration algorithm with redundant bits is presented. The algorithm adds a redundant bit in the SAR ADC, the digital correction circuit in the second stage SAR ADC can calibrate the error back when the first stage Flash ADC error is less than specific offset voltage limits, getting the correct digital output finally. The ADC adopts a "3+10" two-step pipeline architecture, and is simulated in SMIC 0.18 μm complementary metal-oxide-semiconductor(CMOS) mixed signal process. When the power supply voltage is 1.8 V, the sampling frequency is 100 MHz and the input signal is close to the Nyquist frequency, the effective number of bits(ENOB) is 10.990 bits, the signal-to-noise ratio(SNR) is 67.973 dB and the spurious-free dynamic range(SFDR) is 95.381 dB after digital calibration. Simulation results show that the algorithm can effectively improve the ADC system performance.
作者
张章
吴宵
解光军
ZHANG Zhang;WU Xiao;XIE Guangjun(School of Electronic Science and Applied Physics,Hefei University of Technology,Hefei 230601,China)
出处
《合肥工业大学学报（自然科学版）》
CAS
北大核心
2020年第2期216-223,共8页
Journal of Hefei University of Technology：Natural Science
基金
国家自然科学基金资助项目(61674049
61404043)
关键词
快闪型模数转换器
逐次逼近型模数转换器
冗余位数字校准
flash analog-to-digital converter(Flash ADC)
successive approximation register analog-to-digital converter(SAR ADC)
redundant digital calibration
