MOS switching circuit with broadband and high linearity

Abstract

The present invention belongs to the technical field of integrated circuit, specifically to a MOS switching circuit with broadband and high linearity. A MOS switch is the main body of the circuit; a grid voltage bootstrap circuit is used for stabilizing a switching tube grid source voltage; a substrate bias effect and a switch source drain parasitic junction capacitance are eliminated by isolating a substrate and enabling the substrate to follow an input signal when the switch is conducted; influences of the parasitic junction capacitance between the substrate and an isolated trap by a pre-charge-suspension structure. The main non-ideal factors of non-linearity generated by a common MOS switch are eliminated by the three aspects; and the linearity of the switch under high, middle and low frequency input signals is improved.

Description

technical field [0001] The invention belongs to the field of integrated circuits, and in particular relates to a MOS switch circuit with wide band and high linearity. Background technique [0002] The design of high-speed, high-precision and low-power analog-to-digital converter (ADC) is the development focus of today's mixed-signal system chip design, and it has a wide range of applications in wireless communication, instrument measurement, military radar and high-definition digital TV. . With the development of software-defined radio (SDR) communication technology in the future, it is increasingly required that the digital part of the transceiver system be as close as possible to the antenna end, and the signal processing work after the intermediate frequency is all handed over to digital processing chips that can be flexibly configured. Therefore, the ADC needs to sample in the intermediate frequency band or even the radio frequency band. This requires that the sampling...

AI Technical Summary

Problems solved by technology

[0004] First, the small-sized switch handles a small frequency band, which cannot meet the use of advanced ADCs;

[0005] Second, when the small-sized switch processes high-frequency signals, the impedance changes drastically, resulting in poor linearity and serious distortion of the signal;

[0006] Third, although the large-size switch of the traditional MOS process also has good high-frequency performance, it has large parasitic effects and poor low-frequency accuracy

[0007] In response to the above problems, there are currently sampling switches made using the BiCMOS process, such as Analog Devices' "16-Bit, 80MSPS / 105MSPS ADC" (Analog Devices AD9640datasheet), etc., which have better bandwidth, better accuracy and linearity, but using this The switch manufactured by the process has high cost and high power consumption, and it is difficult to adapt to the integration of the process

In addition, there are also technologies that use digital methods to calibrate sampling errors later, such as P.Nikaeen and B.Murmann, "DigitalCorrection of Dynamic Track-and-Hold Errors Providing SFDR>83dBup to fin=470MHz", proc CICC, pp161-164, Sept, 2008, but it requires a complex digital signal processing unit and an accurate training sequence generation source, and it also needs a period of startup time for calibration, making this type of design product unsuitable for practical applications

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