What is High Speed PCB Design?

An institution in organizing an Advance Course on PCB Design.
I request you all to please explain what exactly is High speed PCB design and its prospects in industry.

There is no specific definition for high speed on a PCB. It depends on the circuit, the materials, and the environment.

Basically, you are doing a high speed design when the signal intelligence begins to be affected by the circuit layout. A digital signal (the intelligence in contained in the edges of the digital pulses) can be adversely affected by the dielectric of the PCB, the length and width of the tracks, proximty to other signals, and the environment. High speed designers know the theory of signal propagation, and are able to adjust the variables to ensure the data gets to the proper places in the circuit with the intelligence intact. They also must ensure that the energy is contained within the device or circuit so they don't interfere with other equipment.

In analog circuits, high speed means the design is approaching limits that could alter the shape of the signal (the intelligence in analog signals is in the shape). Similar knowledge and requirements to the digital designer apply.

High speed design is the future of electronics. The need for higher data transfer speeds, and higher frequency analog equipment grows each year. There is virtually no industry untouched by digital technology, and every one of those industries wants to be able to make or do more in a shorter period of time. Less time means more productivity, and that means more profit. High speed is the norm in electronics.

So, will you suggest me to go for this course?
Coz, the technology need you have explained are quite encouraging, but what are the future possibilities after starting off in this field? I am just interested to know where and what i may be working on. I hope you get my point!

What you would be working on depends on your personal interests, your skill, and who is willing to hire you. High speed PCB design is used by Sun Microsystems, SpaceX, Intel, Texas Instrument, Cisco, and thousand more big and small businesses around the world. You could be asked to layout motherboards, cell phone boards, DSL routers, rocket instrumentation, proof of concept designs, etc.

PCB design is both science and art. There are numerous ways to make any given board. The art is choosing an arrangement, and the science is knowing how to get the best out of it. If you don't have a passion for electronic design and board layout, find some other line of work. If you're only in it for the money, you probably will never be a really great designer.

I've been an electronic design engineer for over 50 years, and I've been designing PCB's for about 40 of those years. I still find it to be both fun and challenging. The software, and fabrication technology get better every year. Every circuit uses some new technology in design, function, or fabrication. The learning never stops.

@house_cat.
the answer can not be more clear. For last few months, i was thinking to learn PCB design to aid my college projects.
just a last question.
Where do you see the following combination going?
1)A certificate course in Networking knowledge.
2)BE in Electronics and telecommunication eng.
3)A certificate course in Embedded systems.
4) and now a course in high speed PCB design.

thanks in advance.

Interesting discussion!
What is the approximate number where a board is considered high speed?
Is it mHz or GHz or faster?

For example, (this is a made up board) a board has a uP or DSP that processes signals at 30mHz.
Somewhere else on the board is an ethernet port that talks to a PC.
And there is a high speed i2c ADC that supports signals at 3.4mHz.

When laying out this board, are different sections of the board designed to accommodate the different frequencies....or is there just a general rule to the
whole board?

~Nora

To my opinion, high speed domain starts, where transmission line effects as reflected waves take effect. This is surely the case with 100 Mbps ethernet, but also with signals of lower fundamental frequency, if they have sufficient fast edges (respectively higher spectral components). As an example, if you drive your HS I2C with a fast, low impedance driver and observe unwanted signal overshoot at the receiver, you can regard this issue as a topic of high speed PCB design.

You typically have individual design rules for different net classes, they may include detailed routing constraints for critical high speed signals, most likely more than general rules for the board.

INS-ANI said:

Where do you see the following combination going?
1)A certificate course in Networking knowledge.
2)BE in Electronics and telecommunication eng.
3)A certificate course in Embedded systems.
4) and now a course in high speed PCB design.

Click to expand...

If you are any good in the areas covered by your education, you appear to be very employable in a number of industries. I suggest you investigate companies that design the sort of equipment that interests you most. You'll do best as a beginning engineer if you are inspired by the work, and you are among experienced engineers who share your professional interests.

Your educational combination fits automotive electronics, space instrumentation, industrial electronics, consumer electronics, surveillance systems, home entertainment electronics, and a host of others. Don't be afraid to interview - even if your background doesn't fit exactly into your dream job. You have a background in theory (BE), programming (embedded systems), information technology (networking), and physical hardware design (high speed PCB layout) - a well thought out combination.

Added after 1 minutes:

Nora said:

What is the approximate number where a board is considered high speed?
Is it mHz or GHz or faster?

For example, (this is a made up board) a board has a uP or DSP that processes signals at 30mHz.
Somewhere else on the board is an ethernet port that talks to a PC.
And there is a high speed i2c ADC that supports signals at 3.4mHz.

When laying out this board, are different sections of the board designed to accommodate the different frequencies....or is there just a general rule to the
whole board?
~Nora

Click to expand...

As I indicated above, there's no "one size fits all" solution.

Your example with the 30mHz clock has a variety of specific requirements for each of the sections of the board. It can be assumed that the risetimes of the signals in the digital portion of the board will require minimizing and matching path lengths for digital signal timing. Those digital signals will have to be kept away from the analog portions of the ADC circuitry to avoid corrupting the analog data. The ethernet portion of the circuit carries currents generally higher than the logic circuits and will have to be kept away from them, as well as the analog circuitry.

While keeping the signals separated, at the same time you have to interconnect the various portions of the circuit. The interconnects have to be impedance matched source-to-sink to ensure maximum energy transfer and minimum external radiation or coupling. Additionally, your external ports have to satisfy the ethernet protocol and whatever protocol your input ports require, including voltage levels and impedance. The overall circuitry will have to be designed with EMC and safety standards in mind if you plan to sell the finished product commercially.

You can often make a "kludge" board work without understanding what you are doing. However, if you want your board to work well the first time under a wide range of conditions, you need to actually engineer the board. Thumb rules won't get you there - knowledge will.

Thanks for replies.
Can anyone recommend books on PCB layout?
-N_N

If you are any good in the areas covered by your education, you appear to be very employable in a number of industries. I suggest you investigate companies that design the sort of equipment that interests you most. You'll do best as a beginning engineer if you are inspired by the work, and you are among experienced engineers who share your professional interests.

Your educational combination fits automotive electronics, space instrumentation, industrial electronics, consumer electronics, surveillance systems, home entertainment electronics, and a host of others. Don't be afraid to interview - even if your background doesn't fit exactly into your dream job. You have a background in theory (BE), programming (embedded systems), information technology (networking), and physical hardware design (high speed PCB layout) - a well thought out combination.

Click to expand...

Thanks for your advice sir. i am really encouraged.
However, the biggest problem i face is exposure and
training. I hope by the time of company placements, i will still remember what i have learnt as its unlikely i am going to have any follow up by then...
But your post does tell me what to do.
Thanks!

Nora said:

Can anyone recommend books on PCB layout?
-N_N

Click to expand...

There are several that are considered as standard references:

High-Speed Digital Design, A Handbook of Black Magic
Howard W. Johnson and Martin Graham
Prentice Hall, 1993; ISBN 0-13-395724-1

Advanced Black Magic
Howard W. Johnson and Martin Graham
Prentice Hall, 2003; ISBN 0-13-084408-X

( http://www.sigcon.com/ )

Signal Integrity Simplified
Eric Bogatin
Prentice Hall PTR (September 22, 2003)
ISBN-10: 0130669466
ISBN-13: 978-0130669469

( **broken link removed** )

Signal Integrity Issues and Printed Circuit Board Design
Douglas Brooks
Prentice Hall, 2003
ISBN 0-13-141884-X

( http://www.ultracad.com/prenticehall/prentice hall.htm )

Right the First Time, A Practical Handbook On High-Speed PCB And System Design
By Lee W. Ritchey and John Zasio

( **broken link removed** )

For a general coverage of all aspects of PCB layout and fabrication:

Coombs' Printed Circuits Handbook
Clyde F. JR. Coombs
McGraw-Hill, Hardcover, 5th Bk&CD edition, Published August 2001
ISBN 0071350160

( http://www.bookpool.com/sm/0071350160 )

The above represents several hundred US dollars in reference material. However, if you intend to be a professional designer, they are a good collection to have at your disposal.

@housecat

can you please have a look at the course structure and advice if i being a third year eng student can go for it
plz check the details here

I don't see anything in the course description that should be difficult for a third year student. It appears that the material is more on the practical side than the theoretical side. From the description, I wouldn't anticipate the mathematical theory to be presented at a level beyond intermediate calculus. In fact, I suspect that ordinary algebra would be the most required in the Signal Integrity discussion.

Given what you've already mentioned in this thread about your interests and educational background, this sounds like a good course.