《AN-1142 Tech for high speed ADC PCB layout》.pdf

AN-1142 APPLICATION NOTE One Technology Way •P.O. Box 9106 •Norwood, MA 02062-9106, U.S.A. •Tel: 781.329.4700 •Fax: 781.461.3113 • Techniques for High Speed ADC PCB Layout by Rob Reeder INTRODUCTION from the die to a central point under the part. Note the lack of In today’s industry, the layout of the system board has become ground pins in many converters and amplifiers today. The an integral part of the design itself. Therefore, it is of paramount EPAD is the reason why. importance that the designer has an understanding of the The key is to tie this pin down, that is, soldered well to the PCB mechanisms that affect the performance of a high speed signal to make a robust electrical and thermal connection. When this chain design. connection is not solid, havoc can occur. In other words, the There are many options to consider when it comes to laying design may not work. out a printed circuit board (PCB) in a high speed analog signal Achieving the Best Connection chain design. Some options matter more than others, and some There are three basic steps to take to achieve the best con- are application dependent.