Control of Noise, EMI and Signal Integrity
in High Speed Circuits and PCBs
Rick Hartley – RHartley Enterprises
(Formerly L-3 Avionics Systems - retired)
*The Issue*
When time-varying signals travel in the transmission lines of a printed
circuit board, state changing electric and magnetic fields are present.
When *not* contained, these fields are the energy source of noise, EMI and
signal integrity issues.
“Noise” is “intentional energy” which we fail to contain. Uncontrolled
energy generates many forms of interference. Some circuits are noisy, while
others are not? With the right training the reasons are easily understood!
Compounding the problem are today’s extremely fast ICs. A circuit with 200
ps rise time devices can generate serious problems whether clocked at 2MHz,
200MHz or 2GHz.
*Training that Works*
Knowing how to design circuits and PCBs to contain fields and to control
the effects of high speed devices are the keys to successful design of low
noise circuits. This two-day workshop – completely updated over the past
two years – is a crisp focus of the issues PCB designers and engineers need
to know to prevent EMI, signal integrity, crosstalk and grounding problems
in high speed digital and mixed signal designs. Topics include:
• Impact of frequency on PCB layout
• Frequency – analog *vs.* digital
• Basic essentials of grounding
• Noise – what is it and why it occurs
• Where energy travels in circuits
• Transmission lines and return current paths
• Critical Importance of proper plane assignment
• Common misuse of planes
• Routing and reflections
• Propagation time and velocity
• Lumped *vs.* distributed length lines
• Impact of nearby traces on impedance
• Importance of reflection mode switching
• New thoughts on line termination
• Impact of long Ts in transmission lines
• Proper DDR routing
• Vcc and ground bounce
• Cross talk … what is it … exactly
• Differential pair basics
• Differential impedance … what really matters
• Differential pair cross talk
• Differential pair length matching and skew issues
• Basic types of EMI
• Antenna basics and PCB radiators
• Keys to controlling common mode energy
• Power distribution and decoupling
• IC impact on power system noise
• Decoupling boards without power planes
• Decoupling conventional 4-layer boards
• Decoupling high layer count boards
• Impact of via and plane inductance
• Analog IC decoupling
• Ferrites in the power bus
• Switch mode power – function layout and EMI control
• Basic component placement issues
• Board routing to control EMI and noise
• Impact of connector pin assignments
• Extreme importance of PCB stack-up
• PCB stack-ups that work for SI and EMI control
• I/O filtering and blocking
• Metal vs. plastic enclosures
• Slots and openings in enclosures
• Proper shielding of cables, low and high frequency
• Extreme Importance of I/O connector placement
• How many cables inside the system?
• Routing of internal and external cables
• Multiple boards in the system
• Heatsinks and EMI
• Using chassis as a heatsink.
Each attendee will receive a color PDF of the overheads, as well as a
reduced set for printing, both of which can be utilized for note taking and
future reference.
Richardson, TX
April 18 & 19, 2017 <http://regonline.com/pcb2day2017TX>
Chelmsford, MA
May 16 & 17, 2017
<https://www.regonline.com/registration/Checkin.aspx?EventID=1908138>
For more info: www.pcb2day.com
*About the Instructor*
Rick Hartley (retired from L-3 Avionics) is the principal of RHartley
Enterprises, through which he consults and teaches internationally to
resolve noise, signal integrity and EMI issues. Rick has helped major
corporations in the US and 12 other countries. His 51-year career focused
on circuits and PCBs for the telecom, computer and aircraft avionic worlds.
Rick’s consulting focuses on those same industries, as well as the
automotive and appliances. He has dedicated the past 41 years to
development of PCB and circuits with specific emphasis on control of noise,
EMI & SI in the digital, analog and RF domains. Rick has taught at IEEE
events, is a member of the IPC Designers Council Executive Board, serves on
several IPC subcommittees and is a past member of the Editorial Review
Board of *Printed Circuit Design* Magazine. He has also written numerous
technical papers and articles on methods to control noise, EMI and signal
integrity.
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