《TUT5450-PCB Grounding with Mixed-Signal Chips》.pdf

Maxim Design Support Technical Documents Tutorials A/D and D/A Conversion/Sampling Circuits APP 5450 Maxim Design Support Technical Documents Tutorials Amplifier and Comparator Circuits APP 5450 Maxim Design Support Technical Documents Tutorials Analog Switches and Multiplexers APP 5450 Keywords: PCB, mixed-signal, layout, ground, grounding, grounds, printed circuit board TUTORIAL 5450 Successful PCB Grounding with Mixed-Signal Chips —Follow the Path of Least Impedance By: Mark Fortunato, Senior Principal Member of Technical Staff Oct 15, 2012 Abstract: This tutorial discusses proper printed-circuit board (PCB) grounding for mixed-signal designs. For most applications a simple method without cuts in the ground plane allows for successful PCB layouts with this kind of IC. We begin this document with the basics: where the current flows. Later, we describe how to place components and route signal traces to minimize problems with crosstalk. Finally, we move on to consider power supply-currents and end by discussing how to extend what we have learned to circuits with multiple mixed-signal ICs. A similar version of this article appears in three parts on EDN, August 27, 2012, September 11, 2012, and September 17, 2012. Introduction Board-level designers often have concerns about the proper way to handle grounding for integrated circuits (ICs), which have separate Attend this brief webcast by Maxim on TechOnline analog and digital grounds. Should the two be completely separate and never touch? Should they connect at a single point with cuts in the ground plane to enforce this single point or Mecca ground? How can a Mecca ground be implemented when there are several ICs that call for analog and digital grounds? This tutorial discusses proper printed-circuit board (PCB) grounding for mixed-signal designs. For most applications a sim