Broadband tracking and holding circuit with good high-frequency linearity

Abstract

The invention belongs to the field of integrated circuits, and particularly relates to a broadband tracking and holding circuit with good high-frequency linearity. The circuit comprises an input buffer, a main switch circuit, an output buffer and an auxiliary switch circuit. According to the tracking and holding circuit provided by the invention, when in a holding state, devices in the input buffer cannot enter a saturated state, and the devices always main a forward amplification state during the whole working process, so that the establishment efficiency of signals can be significantly improved, and the maximum sampling bandwidth of the circuit can be improved; and when in the holding state, an analog signal input end of the main switch circuit is at a fixed level, high-frequency analogsignals that are externally input cannot cause interference to holding signals on a sampling capacitor, and thus the high-frequency linearity can be improved. The circuit provided by the invention canbe applied to the front-end sampling of a high-speed analog-to-digital converter, and can enhance the input bandwidth and the high-frequency linearity of the high-speed analog-to-digital converter.

Description

technical field [0001] The invention belongs to the field of integrated circuits, in particular to a wideband tracking and holding circuit with good high-frequency linearity. Background technique [0002] A / D Converter ADC is a data conversion system that converts analog signals into digital signals, and is the interface between the analog world and digital processing systems. With the improvement of application requirements, the frequency of the analog signal processed by the analog-to-digital converter is getting higher and higher, which has reached the order of several GHz, and the ADC is required to have a very high analog input bandwidth and good sampling linearity. The design of the ADC at the technical level brings great challenges. In order to solve such problems, the sampling front-end circuit can be used to sample the high-frequency signal before the high-speed ADC, and then the subsequent ADC will sample and quantize the sampled discrete signal. , the sampling fr...

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Problems solved by technology

[0006] In order to overcome the problems existing in the prior art, the present invention proposes a new tracking and holding circuit, which has high sampling bandwidth and very good high-frequency linearity, and solves the problems of low signal bandwidth and high analog input frequency of traditional tracking and holding circuits. The problem of time linearity degradation

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