Fully differential ADC with rail-to-rail common-mode range and nonlinear capacitor compensation
Fully differential ADC with rail-to-rail common-mode range and nonlinear capacitor compensation
复制标题
DOI：
10.1109/4.50301
复制
发表时间：
1990-02
影响因子：
5.4
通讯作者：
R. Hester;K. Tan;M. D. Wit;J. Fattaruso;S. Kiriaki;J. Hellums
中科院分区：
文献类型：
--
作者：
R. Hester;K. Tan;M. D. Wit;J. Fattaruso;S. Kiriaki;J. Hellums
电容电压依赖性是电荷再分配模数转换器（adc）非线性的来源之一。虽然有可能通过电容器制造技术的改进来解决这个问题，但出现了使用电路技术更可取的情况。传统的全差分电荷再分配变换器拓扑结构消除了与电容线性电压系数成正比的误差，但其比较器受到共模输入信号的影响。当转换不平衡差分信号时，线性度只能通过较大的比较器共模抑制来实现。提出了一种替代差分转换器拓扑，该拓扑将比较器与输入共模信号隔离开来，从而产生-73 dB的共模抑制比。此外，还介绍了一种消除二次电容电压系数误差的电路。测量表明，它能够将变换器的线性度提高一个数量级。>
One of the sources of nonlinearity in charge redistribution analog-to-digital converters (ADCs) is capacitor voltage dependence. While it is possible to address this problem through capacitor fabrication technology improvements, situations arise where it is more desirable to use circuit techniques. The conventional fully differential charge redistribution converter topology eliminates errors proportional to the capacitor linear voltage coefficient, but its comparator is subjected to the common-mode input signal. When converting unbalanced differential signals, linearity is achieved only with large comparator common-mode rejection. An alternative differential converter topology that isolates the comparator from the input common-mode signal, resulting in a common-mode rejection ratio of -73 dB, is presented. In addition, a circuit that cancels the error caused by the quadratic capacitor voltage coefficient is described. Measurements show that it is capable of increasing the converter linearity by an order of magnitude. >