Design-oriented estimation of thermal noise in switched-capacitor circuits
Design-oriented estimation of thermal noise in switched-capacitor circuits
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DOI：
10.1109/tcsi.2005.853909
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发表时间：
2005-11-01
影响因子：
5.1
通讯作者：
Temes, GC
中科院分区：
文献类型：
--
作者：
Schreier, R;Silva, J;Temes, GC
热噪声是大多数电子电路性能的一个主要限制因素。它在开关电路中尤为重要，例如在混合模式CMOS集成电路中广泛使用的开关电容（SC）滤波器。在这些电路中，由于混叠，开关会使热噪声的功率谱密度提高。不幸的是，尽管开关电容电路中的噪声理论在文献中有讨论，但它非常复杂。开关电路中噪声的数值计算非常繁琐，并且需要高度复杂且不常见的软件。本文有两个目的。它对开关电容电路在处理噪声时发生的物理现象进行了指导性描述（第二至三节）。它还提出了一些专门但高效的算法，用于估计开关电容电路中产生的采样噪声，这些算法只需要简单的计算（第四至六节）。还描述了一种直接从估计得出的实用设计流程。通过使用SpectreRF进行仿真，验证了所提出的估计算法的准确性。作为一个例子，它被应用于估计一个二阶低失真Δ - Σ转换器中的总热噪声。
Thermal noise represents a major limitation on the performance of most electronic circuits. It is particularly important in switched circuits, such as the switched-capacitor (SC) filters widely used in mixed-mode CMOS integrated circuits. In these circuits, switching introduces a boost in the power spectral density of the thermal noise due to aliasing. Unfortunately, even though the theory of noise in SC circuits is discussed in the literature, it is very intricate. The numerical calculation of noise in switched circuits is very tedious, and requires highly sophisticated and not widely available software. The purpose of this paper is twofold. It provides a tutorial description of the physical phenomena taking place in an SC circuit while it processes noise (Sections II-III). It also proposes some specialized but highly efficient algorithms for estimating the resulting sampled noise in SC circuits, which need only simple calculations (Sections IV-VI). A practical design procedure, which follows directly from the estimate, is also described. The accuracy of the proposed estimation algorithms is verified by simulation using SpectreRF. As an example, it is applied to the estimation of the total thermal noise in a second-order low-distortion delta-sigma converter.