Circuit Layout Techniques And Tips (Part I of
VI)
by Bonnie C. Baker, Microchip Technology Inc.
The Art Of Laying Out Two-Layer Boards
In this highly competitive, battery-powered marketplace, cost objectives
usually dictate that a designer use two-layer boards in the design. Although
the multi-layer board (4-, 6- and 8-layers) allows the designer to build
cleaner solutions in terms of size, noise and performance, financial pressures
force the engineer to rethink layout strategies with the two-layer board
in mind. In this article we discuss the use or misuse of auto-routing, the
concept of current return paths with and without ground planes, and recommendations
for component placement where two-layer boards are concerned.
Pay Now Or Pay Later With The Auto-Router And Analog Circuits
It is tempting to use the auto-router when designing printed circuit
board (PCB.) More often than not, a purely digital board, (especially if
the signals are relatively slow, and the circuit density is low) will work
just fine. But as you try to lay out analog, mixed-signal or high-speed
circuits with the auto-routing tool that is available with your layout software
there may be some issues. The probability of creating serious circuit performance
problems is very real.
...download complete Part I here (self-extracting WINZIP file, 508k, extracts to PDF file)