28.4 A 12b 330MS/s pipelined-SAR ADC with PVT-stabilized dynamic amplifier achieving <1dB SNDR variation
28.4 A 12b 330MS/s pipelined-SAR ADC with PVT-stabilized dynamic amplifier achieving <1dB SNDR variation
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具有 PVT 稳定动态放大器的 28.4 A 12b 330MS/s 流水线 SAR ADC，可实现 <1dB SNDR 变化
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Y. Chiu
中科院分区：
文献类型：
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作者：
Hai Huang;Sudipta Sarkar;Brian Elies;Y. Chiu
在高速流水线或流水线SAR ADC中，由于建立速度和精度要求严格，传统的基于运算放大器的残差放大器会消耗大量功耗。最近的一种替代方法采用动态放大器[1]来实现更有效的建立形式，因为回转比指数建立更节能（图28.4.1）。例如，在6b精度下，动态放大器的设置时间约为具有相同偏置电流的传统运算放大器（非回转）的四分之一。然而，动态放大器的效率伴随着一些不期望的特征，例如不明确的增益、PVT和时钟抖动灵敏度。特别是，由于动态放大器的电压增益与非恒定电阻、负载电容和压摆时间（图28.4.1中分别为gmA、CLA和tA）有关，因此它会随着PVT变化而显著漂移。补偿增益不稳定性的一种方式是采用连续的背景校准。然而，大多数这些校准需要对输入信号的统计特性进行一些约束，并且具有较长的收敛时间和设计复杂性。本文提出了一种简单的模拟方法，有效地稳定电压增益的PVT变化。
In high-speed pipeline or pipelined-SAR ADCs, conventional opamp-based residue amplifiers consume significant amounts of power due to stringent settling speed and accuracy requirements. A recent alternative approach employs a dynamic amplifier [1] to achieve a more efficient form of settling, stemming from the fact that slewing is more power efficient than exponential settling (Fig. 28.4.1). For example, at 6b accuracy, the setting time of a dynamic amplifier is about a quarter of that of a conventional opamp (non-slewing) with the same bias current. However, the efficiency of the dynamic amplifier is accompanied by a few undesirable features such as ill-defined gain, and PVT and clock jitter sensitivity. In particular, as the voltage gain of a dynamic amplifier relates to the non-constant transconductance, load capacitance and slewing time (gmA, CLA and tA, respectively, in Fig. 28.4.1), it can drift dramatically with PVT variations. One way to compensate for gain instability is to employ continuous background calibration. However, most of these calibrations require some constraints on the statistical property of the input signal and suffer from long convergence time and design complexity. This paper presents a simple analog approach to effectively stabilize the voltage gain over PVT variations.