Gain enhanced full-differential amplifier structure for pipeline ADC

Abstract

The invention discloses a gain enhanced full-differential amplifier structure for a pipeline ADC. The structure comprises an MDAC (Multiplying Digital to Analog Converter) master amplifier and two secondary amplifiers. The master amplifier is a telescopic cascode structure. Two PMOS transistors form output impedance Rp of the cascode structure. Two NMOS transistor form the output impedance Rn of the cascode structure. The two secondary amplifiers of an operational amplifier AMP1 and the operational amplifier AMP2 are used for improving the Rp and the Rn. The two secondary amplifiers comprise output voltage stabilizing structures which are used for ensuring the gate voltage stability of the common gate PMOS transistors and the common gate NMOS transistors in the operational amplifier of the full-differential master amplifier. The operational amplifier AMP1 is a two-level operational amplifier. A current input mode is taken as an input mode of a second-level amplifier. The load of a first level-amplifier is reduced. The bandwidth and gain are increased. The gain of the master amplifier is increased from original Gm1*(Rp||Rn)*A2 to Gm1*(AP*Rp||AN*Rn)*A2.

Description

technical field [0001] The invention relates to the field of analog integrated circuits, in particular to a gain-enhanced full-differential amplifier that can be used in pipeline analog-to-digital converter circuits. Background technique [0002] In recent years, with the rapid development of communication and digital signal processing technology, the design of high-speed and high-precision analog-to-digital converters is becoming more and more important as the interface between analog systems and digital systems. As a classic structure, the pipeline analog-to-digital converter can well take into account the requirements of speed, precision and power consumption. Because of its structural design diversity and flexibility, it has been greatly favored. [0003] The basic idea of ​​the pipeline ADC is to disperse the overall precision to all levels of the pipeline, and combine the output of each level through timing control to achieve the overall required precision of the syste...

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Problems solved by technology

Laser correction needs to add additional processes, and the cost is greatly increased; self-calibration circuits need to design new algorithms and implement circuits, which brings huge pressure on design difficulty, power consumption and area; capacitance averaging technology actually sacrifices speed to improve accuracy

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