EE's who do PCB Layout

For real cost effective developement, just sub the whole process out to a low paid engineer in India. It will be in production in no time with minimal cost.

get an idea for how many EE's layout their own PCBs.

We have some pretty strict export controls. That wouldn't be an option.

That's how I do it in my consulting business. Layout is always contracted out. The trick is to establish a good relationship with the layouters. It is impossible to know everything and those guys are specialists. They know the newest trends, what fabs can do and cannot do, which footprints work better than others.

In the same way my clients contract out the difficult parts of analog designs. To me ;-)

All but the simplest production designs get given to the specialists - it isn't a cost effective use of engineer's time.

Prototyping can be rather different. I have a library of standard building block circuits, and their associated pcb design, that I often use for prototyping. I simply put the blocks needed on the layout and put in linking tracks and whatever non-standard elements that are needed. Then send that for fab. I get the boards back from China within the week. The resulting board is, of course, much larger than need be and has a whole lot of unnecessary duplication of things like supply filtering. But it gets a working prototype to show a customer very quickly and cheaply..

All those checks and rechecks are not "just inefficiency". A good layout person will catch stuff an engineer has glossed over or failed to document properly. The review process itself may cause the engineer to notice a dumb mistake before stuff is produced. Of course, that may also fail to be the case...I saw an example many years ago where the layout person did the layout, and the engineer checked it, and errors persisted right into shipped product - errors which I (as an outside consultant working on version control for drawings and PCB art) found within a few hours of doing some basic checks - and I hadn't even completed college at that point. That was not the best-run company.

The checks and rechecks that I'm referring to are done by myself to ensure that the pcb designer has done what I have asked. It's been my experience that anytime any kind of change is made, the whole board must be re-checked. Sometimes, areas of the board that are not supposed to be affected by the change, mysteriously are.

I tend to get pretty involved in the layout (specifying locations/ division of power and ground planes, specifying general routing of critical nets, isolation of analog and digital return paths, etc.). There's a lot of back and forth that takes place between myself and the pcb designer. The level of documentation that would be required to complete express to the pcb designer what is required would be a larger effort than doing the layout myself, hence, the inefficiency. Not to mention, I have to check and recheck until it's finally done right.

I've almost always had a CAD guy to do mechanical drawings, design really, and to lay out PCBs for me. I even draw schematics on paper and let him create the library parts and enter the schematic. We discuss placement, routing, thermal issues, whatever, and he lays out the board and does the whole package: schematic, pcb, fab drawing, assembly drawings, BOM, gerbers, PDF files, front-panel fab and artwork. A decent density multilayer board may take him 3 or 4 weeks for the whole package, and that saves me a lot of time.

I do review the layout in process and check/tweak the final layout before we gerber/release it.

John

At this very moment I'm doing a PCB layout for a 1MHz 130Watt converter. I wouldn't let anybody do the PCB layout for me.. For example, I know the currents, the high frequency traces, the grounding pattern and the parasitic effects. D from BC

I design circuits and layout PCBs. I know I don't do as good a job as a good PCB layout engineer would do. I know I don't know the CAD tools as well and am less efficient than a good PCB layout engineer who uses them every day. I know quite a lot about PCB manufacture, footprints and data preparation etc. I know I don't know as much as I should.

I think you grossly underestimate the amount of knowledge and skill required to be a good PCB layout engineer.

The idea that it would be more efficient for design engineers (without significant previous experience) to layout their own PCBs to avoid information transfer between design and layout engineers is almost farcical. Unless your PCB layout requirements are very modest and/or the layout engineers you have are rubbish.

It's called, "delegation". The idea is that you invest the considerable time and effort *once* to build up a supportive environment and then go on to enjoy the benefits of that environment, year after

Back when I did EE for a living, we had a layout group that did the layouts for the official boards, but we also had Cadstar for smaller boards, and we did those ourselves. At least, I did. The layout group was often too busy to "get to it" in a reasonable time.

These days, I do all my own layouts, but only because I don't do EE for a living any more (I do software for a living now). I find that I work on the schematics and layout at the same time during the second half of the project (once there's enough schematics to even start the layout), as the needs of the layout may require changes in the schematics, mostly pin swapping.

Of course, the fact that I'm one of the authors of PCB makes me biased ;-)

I can be, but only if the design engineer is not only good at PCB layout, but efficient as well. Being a good design engineer does not imply one is also good at PCB design, nor efficient for that matter. You can get superb designers who can't operate the software tools to save their life.

Yes it is, for better and for worse. Every company is different though.

I've found it fairly rare where *every* design engineer in a company will lay out their own board. Usually you end up with either your own in-house PCB group, or the PCB work gravitates toward the engineer with the best PCB skills, or the work is simply contracted out (fairly common for very large designs). Not every company likes to have their design engineers tied up for several weeks laying out some huge board.

Dave.

Your workplace sounds exactly like the various commercial places that I've worked.

When I've had the chance I've always checked the printed circuit layouts agains the schematic - not so much to make sure that all connections are correct, because printed circuit draftspersons can be relied on to get that right, but so I get to see where every last track goes, where things can go wrong.

Most of the places I've worked wouldn't let me spend the time required.

On one occasion, the experts in the drawing office knew that the order of layers within a multilayer board didn't matter, and ignored my explicit instructions about where to put the various ground planes in a board where a lot of high speed signals were being routed along transmission lines. It took as quite a while to find out why the board wasn't working right.

When I was working at Nijmegen University I was able to get my hands on a copy of their printed circuit layout program and did lay out a couple of sensitive boards. It worked out fairly well. The boards worked, and it didn't take me all that long to lay them out. I didn't bother laying out less sensitive boards - the draftsmen paid attention to the constraints I put in the layout and produced tidy layouts that worked fine.

-- Bill Sloman, Nijmegen

Occasionally I have done so, but it is inefficient. Unles you do it often you're usually not good at it. Better use of my talents is for me to direct the designer.

Mark Walter, EE

Much depends on

1. The design
2. The electrical designer
3. The layout engineer
4. Communication between 2 and 3
5. Properly set constraints in the design by 2

Layout includes a great deal of specialist things most EEs don't do or know (setting up the board, setting up the stack, footprint generation etc) that layout people are trained to do and generally do very well. In those areas it is not a reasonable to expect the electrical designer to know or do those things, just as it is not reasonable to expect the layout person to understand all the details of why I may have set (for instance) net spacing rules.

Once well into layout, I have actually done some of the layout for a number of reasons. Generally I tell my layout people what must be done (and set rules at the top level so they are guided anyway). Done properly, there is no reason this needs to be inefficient.

Cheers

PeteS

In the past I had a contract layout guy who would do what I asked on a specific change but at the same time change back something that was previously changed - quite annoying.

Cheers

PeteS

BJ (..what a nick..), I'm completely doing my own pcb's through to the prototypes and perhaps small series of 10 or so. There is so much knowledge in doing the pcb's, that is rather hard to transport. The usual schematic and layout tools do not provide any support for such knowledge. Just consider the GND symbol on the schematic. It stands for an equal potential. Yet, it has to be treated differently whether you're doing sensitive sensing in a high current environment or in RF.

Thus a design of mine is delivered as stuffed pcb, and an optional schematic is just a reference.

Rene

I mostly do my own layouts. The main reason is that while doing the layout changes (pins swaps) in the circuit diagram may lead to more optimal placement and circuits which are easier to route.

Yes, I do everything too (circuit design, PCB layout, prototype build, testing, software). It seems to work OK. One advantage is that I can easily change things around to suit the layout, for example re-allocate microcontroller I/Os, without conferring with someone else each time.