Table Of Content

Fabricating Printed Circuit Boards [This page intentionally left blank.] Fabricating Printed Circuit Boards Jon Varteresian An impr int of Elsevier Science Amsterdam London New York Oxford Paris Tokyo Boston San Diego San Francisco Singapore Sydney Newnes is an imprint of Elsevier Science. Copyright © 2002, Elsevier Science (USA). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Recognizing the importance of preserving what has been written, Elsevier Science prints its books on acid-free paper whenever possible. Library of Congress Cataloging-in-Publication Data ISBN: 1-878707-96-5 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. The publisher offers special discounts on bulk orders of this book. For information, please contact: Manager of Special Sales Elsevier Science 225 Wildwood Avenue Woburn, MA 01801-2041 Tel: 781-904-2500 Fax: 781-904-2620 For information on all Newnes publications available, contact our World Wide Web home page at: http://www.newnespress.com 10 9 8 7 6 5 4 3 2 1 Printed in the United States of America Dedication For Katie and Emma, my brightest stars. [This page intentionally left blank.] Introduction .......................................................................... xi Safety .................................................................................................. xiii The Schematic Symbol ....................................................................... 1 1 Schematic Capture............................................................ 1 Symbol Properties............................................................................... 3 Schematic Generation......................................................................... 4 Generating a Netlist ............................................................................ 8 2 Basic Circuit Board Placement and Routing Considerations ..................................................................... 11 Circuit Board Placement and Routing Basics ..................................... 11 Placement and Routing Guidelines..................................................... 21 General Placement Considerations .................................................... 24 General Routing Considerations ......................................................... 25 3 Placement and Routing Considerations for Various Circuit Designs ..................................................................... 35 Placement and Routing Considerations for General-purpose............. 35 Analog Circuit Boards ......................................................................... 35 Placement and Routing Considerations for General-purpose............. 35 Digital Circuit Boards........................................................................... 35 Placement and Routing Considerations for High-performance ........... 37 Analog Circuit Boards ......................................................................... 37 Placement and Routing Considerations for High-speed Digital .......... 39 Circuit Boards...................................................................................... 39 Placement and Routing Considerations for RF Circuit Boards ........... 42 Special RF Routing Techniques: Microstrip ........................................ 47 Special RF Routing Techniques: Stripline........................................... 53 4 Real World Guidelines for Commercial Fabrication Houses .................................................................................. 57 Design Guidelines ............................................................................... 57 Sample Fabrication House Guidelines................................................ 61 Nexlogic Technologies Design Guidelines .......................................... 62 Capital Electronics Design Guidelines ................................................ 63 Generation of Design Files.................................................................. 64 A Photoplotter Tutorial........................................................................ 65 Vector Photoplotters............................................................................ 66 Raster Photoplotters ........................................................................... 66 5 Making Printed Circuit Boards......................................... 69 Exposing and Developing the Resist Layer ........................................ 71 Etching the Printed Circuit Board ........................................................ 79 Tin-Plating the Printed Circuit Board ................................................... 81 Drilling and Shaping the Printed Circuit Board.................................... 83 6 Project Plans...................................................................... 89 Exposure Cone ................................................................................... 89 Building the Exposure Cone................................................................ 90 Building the Exposure Frame.............................................................. 94 Material List for the Exposure Frame.................................................. 96 7 Resource List..................................................................... 97 General Supplies................................................................................. 97 Commercial Printed Circuit Board Fabrication Houses ....................... 105 Design Services .................................................................................. 106 APPENDIX A Data Monitor Project ..................................... 107 How It Works ....................................................................................... 109 System Requirements ......................................................................... 110 Description of Data Monitor Hardware ................................................ 110 Personality Module.............................................................................. 116 Installation and Description of Data Monitor Software ........................ 120 Data Monitor Operation....................................................................... 121 Message Structure .............................................................................. 134 Firmware Flow Overview..................................................................... 158 Initialize Routine .................................................................................. 161 Data Monitor Schematics and PCB Foils ............................................ 173 Data Monitor Parts List........................................................................ 188 APPENDIX B Building the Data Monitor............................. 191 Skills Needed ...................................................................................... 191 Equipment Needed ............................................................................. 192 Building the Power Supply Section ..................................................... 193 Testing the Power Supply Section ...................................................... 194 Building the RS-232 Interface Section ................................................ 194 Building the Microprocessor Section ................................................... 195 Building the LED Status Section ......................................................... 197 Installing the Personality Module Connectors ..................................... 197 Preparing the Chassis ......................................................................... 198 Mounting the Circuit Board into the Chassis ....................................... 202 General I/O-Temperature Personality Module Assembly Instructions.......................................................................................... 203 Building the Analog Input Section ....................................................... 203 Building the Digital Input Section ........................................................ 204 Building the Temperature Sensor Section .......................................... 205 Attaching the Host Connectors ........................................................... 206 Mounting the General I/O-Temperature Module into the .................... 207 Data Monitor........................................................................................ 207 Assembling the Input Breakout Connector.......................................... 208 Testing the Data Monitor ..................................................................... 208 APPENDIX C Data Monitor Temperature Sensor Application Note ................................................................... 215 Setting Up the Data Monitor ................................................................ 217 Configuring the Data Monitor .............................................................. 218 Monitoring ........................................................................................... 219 Downloading ....................................................................................... 220 Analyzing............................................................................................. 221 Variations ............................................................................................ 222 Glossary ................................................................................ 225 Index ...................................................................................... 233 Introduction How difficult is it to design and fabricate printed circuit boards? When you look at a finished printed circuit board—with an often-complex circuit pattern and a mixture of through-hole and surface mount components— you may think creating your own boards would be a difficult, time-consuming task that would require specialized tools and expertise. However, fabricating your own printed circuit boards can be broken down into the following rela tively simple steps: 1. Generation of the schematic. 2. Placement and routing of the circuit board. 3. Generation of artwork. 4. Exposing and developing the resist layer. 5. Etching the printed circuit board. 6. Tin plating of the printed circuit board. 7. Drilling and shaping, including vias (or barrels). Depending upon your particular situation, you may not need to complete all of the steps listed above. The purpose of this book is to explain each of the steps so you can create your own professional-quality printed circuit boards. The method of producing printed circuit boards described in this book is unique. It is a result of years of trial and error and lots of ruined circuit boards! What makes this process unique is that you don’t need photographic equipment, lots of strange and dangerous chemicals, or expensive traditional artworks. All artworks used in this process are printed on plain white paper—no transparen cies or commercially produced photoplots are needed! You can generate these artworks directly from your own laser printer, ink jet printer, or copier. This xi