Design Of High-Precision ADC Clock System

A typical representative of the high-speed device is a high speed digital to analog digital converter(ADC)as well as its clock system and amplifier system.The ADC system is widely used in signal acquisition,data conversion,wireless survey and so on,whose rising edge rate of the clock rate are to picosecond-level computing.Traditional low-speed circuit design rule cannot meet the actual needs of multilayer,high-speed ADC circuit board.In order to make a comprehensive analysis of ADC such as reflection,crosstalk,overshoot,electromagnetic interference and so on,we need to consider the high-frequency effect,transmission line effects and electromagnetic interference at same time,and establish reasonable testing and verification flow when we face transmission of high frequency mixed signal.PCB board FR-4 is mostly used in the semiconductor technology and board-level interconnects,since the high-speed signals on the PCB is opacity.We make an application system design based on PCB board of an analog-to-digital converter chip(ADC)AD9250 whose conversion rate is 250 MSPS and propose a solution to improve the stability of high-speed ADC clock circuit.First of all,we design a clock stabilization circuit based on AD9517-1 for the ADC.Then we design a third-order loop filter whose center frequency is 250 MHz and phase noise is-98.7 dBc/Hz on the basis of previous work.At last,we make signal integrity analysis and output simulation for the system from circuit design and board-level interconnects two angles.With the help of ADIsimCLK and Advanced Design System,we make simulation and analysis of system clock signal synchronized and the transmission quality problems in the analog to digital conversion system.According to the high frequency transmission line theory,we conduct a network matching design based on FR-4 technology and optimize the strategies of place and route.For this purpose,this paper designs an efficient and high stability clock system to improve the accuracy and efficiency of ADC,and be texted on the FR-4.It has practical significance for design and application of high speed data conversion systems.