operational transconductance amplifiers

An improved reversed miller compensation technique for three-stage CMOS OTAs with double pole-zero cancellation and almost single-pole frequency response

This paper presents an improved reversed nested Miller compensation technique exploiting a single additional feed-forward stage to obtain double pole-zero cancellation and ideally single-pole behavior, in a three-stage Miller amplifier. The approach allows designing a three-stage operational transconductance amplifier (OTA) with one dominant pole and two (ideally) mutually cancelling pole-zero doublets. We demonstrate the robustness of the proposed cancellation technique, showing that it is not significantly influenced by process and temperature variations.

0.9-V class-AB Miller OTA in 0.35-?m CMOS with threshold-lowered non-tailed differential pair

This paper presents a CMOS operational transconductance amplifier (OTA), suitable for sub-1-V supply applications, whose (input) common-mode voltage can be set to (VDD+VSS)/2 thanks to two combined techniques applied to the differential pair, namely, threshold voltage lowering and elimination of the tail current generator. Both techniques are implemented through a single common-mode feedback loop, which embeds the shared bulk terminal of the pair.

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