Multistage amplifiers are a reliable method of achieving high gain in systems where the voltage supply is low. The common practice is to prefer 3-stage amplifiers over 4-stage ones when a gain of < 120 dB is required, since the former are easier to compensate. In this article, we employ four stages to relax the constraints on each stage. An extension of the single-Miller-capacitor compensation and active-parallel compensation to a 4-stage operational transconductance amplifier (OTA) design in this work is capable of driving a capacitor range of 400 pF to 12 nF( $30\times $ ) by consuming a total power of about 175 mW and occupying only 0.007 mm2. This design achieved a unity-gain frequency (UGF) > 1.18 MGz and a phase margin (PM) of > 48° for all drivable load values. The proposed design, implemented in a standard CMOS 130-nm process, can drive a wide range of load capacitors without sacrificing any aspect of performance.

中文翻译：

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具有宽负载范围 (400 pF-12 nF) 的 175.2mW 4 级 OTA，使用有源并行补偿

多级放大器是在电源电压较低的系统中实现高增益的可靠方法。当需要 < 120 dB 的增益时，通常的做法是选择 3 级放大器而不是 4 级放大器，因为前者更容易补偿。在本文中，我们采用四个阶段来放松每个阶段的约束。在这项工作中，将单米勒电容器补偿和有源并联补偿扩展到 4 级运算跨导放大器 (OTA) 设计，能够驱动 400 pF 至 12 nF（$30\times $）的电容器范围总功耗约为 175 mW，仅占用 0.007 mm2。对于所有可驱动负载值，此设计实现了单位增益频率 (UGF) > 1.18 MGz 和相位裕度 (PM) > 48°。建议的设计，在标准 CMOS 130 纳米工艺中实现，