Research And Design Of Ultra Wide-band High Speed Sampling And Holding Circuits

The analog-to-digital conversion circuit(ADC)is an important circuit for achieving signal acquisition function.The demand for ultra-wide-band high-speed analog-to-digital conversion circuits in high-speed communication applications such as radar and 5G is enormous,and it is also a bottleneck problem that urgently needs to be overcome in China.The sampling and holding circuit,as the data acquisition terminal of the analog-to-digital conversion circuit,is a key circuit module that determines its speed,bandwidth,and accuracy.Therefore,this article mainly focuses on the ultra-wide-band high-speed design technology of sampling and holding circuits.This article provides a systematic introduction to the basic principles and performance indicators of sampling and holding circuits,analyzes the characteristics of track and hold and sample and hold circuit structures,and explores the common structures of input buffers and sampling switch circuits in sampling and holding circuits.On this basis,in response to the problem of poor accuracy in traditional sampling and holding circuits under high-speed operation,this thesis proposes an ultra-wide-band high-speed sampling and holding circuit based on a new type of gate voltage bootstrap switch circuit.While using the bottom plate sampling technology,a transmission gate structure is used at the input signal input end to further reduce the charge injection effect.The specific circuit design and simulation are completed based on the 28 nm CMOS process.The simulation results show that the new gate voltage bootstrap switch circuit has increased the spurious free dynamic range(SFDR)from 62 d B in the traditional sampling and holding circuit to 73.3d B under ultra-wide-band high-speed operating conditions with an input sine signal frequency of 950 MHz and a sampling clock signal frequency of 4GHz.The overall signal-to-noise distortion ratio(SNDR)of the sampling switch circuit has reached 69.5d B,the spurious free dynamic range(SFDR)has reached70.3d B,the total harmonic distortion(THD)has reached-68.5d B,and the effective bit(ENOB)has reached 11.2 bits,achieving good accuracy while achieving ultra-wide-band high-speed operation.