High-gain large-broadband three-level operational amplifier applicable to pipelined analogdigital converter

Abstract

The invention relates to a high-gain large-broadband three-level operational amplifier applicable to a pipelined analogdigital converter. The operational amplifier comprises a first-level amplification module 201, a second-level amplification module 202, a third-level amplification module 203, a first compensation module 204, a second compensation module 205, a first loading capacitor CL1 and a second loading capacitor CL2, wherein the second-level amplification module 202 comprises a first amplification unit 2021 and a second amplification unit 2022. According to the high-gain large-broadbandthree-level operational amplifier applicable to the pipelined analogdigital converter, a current offset technology is adopted, on one hand, the gain of a first-level amplifier can be increased, on the other hand, common-mode feedback circuits can be reduced, and the area and power dissipation are reduced; meanwhile, a current mirror circuit is adopted, on one hand, the gain of the circuit can beincreased, on the other hand, transconductance of a second-level amplifier is positive, and a simple five-pipe total-differential operational amplifier is adopted as a third-level amplifier, and the output oscillation amplitude can be increased.

Description

technical field [0001] The invention relates to the technical field of analog integrated circuits, in particular to a three-stage operational amplifier with high gain and large bandwidth suitable for pipeline analog-to-digital converters. Background technique [0002] Increasing demand from the semiconductor and communications industries has accelerated the development of analog integrated circuits. As an important module in analog integrated circuits, operational amplifiers are widely used in bandgap references, analog-to-digital converters (A / D converters) and data converters. [0003] Analog-to-digital converters (A / D converters) are widely used in electronic information systems such as wireless communication systems and radars. The speed and precision of the ADC often directly determine the core performance of the entire information sampling system, so higher requirements are put forward for its performance. Pipelined ADC (Pipelined ADC) can take into account the requi...

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Problems solved by technology

[0004] However, as the feature size of MOS devices continues to decrease, the power supply voltage becomes lower and lower, and the intrinsic gain of MOS tubes becomes lower and lower. In high-speed and high-precision pipeline A / D converters, multi-stage operational amplifier structures and automatic gain are usually used. However, under the TSMC (TSMC) 65nm process, when the power supply voltage is 1.2V, the gain bootstrap op amp structure makes some tubes work in the unsaturated region, which reduces the stability of the design

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