EE's who do PCB Layout

I would like to get an idea for how many EE's layout their own PCBs. Where I work, the EE's author the schematics, provide some layout
guidence for critical nets (high current/frequency, etc.) and parts placement and utlimately act as a checker for the final layout. The latter ususally ends up being multiple time consuming checking iterations. This process has some inate inefficiencies due to the amount of detail that is communicated between the engineer and pcb designer and all the checks and rechecks that occur. It seems to me that the process of designing a circuit board from start to finish would be much faster and more cost effective (due to the improved efficiency) if the engineer were to handle the pcb layout. Is this a common practice in industry?
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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.
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We have some pretty strict export controls. That wouldn't be an option.
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Long Ranger wrote:

Bwahahahaahahahaha !
Have you actually ever dealt with the Indians ? I have !
Graham
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snipped-for-privacy@hotmail.com says...

I took the statement kinds' tongue in cheek. Do you think he was being serious?
Jim
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James Beck wrote:

Who can tell ?
Management types certainly believe that kind of thing. Been there, done that, had to fix it.
Graham
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BJ wrote:

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 ;-)
--
Regards, Joerg

http://www.analogconsultants.com
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BJ wrote:

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..
--
Sue





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BJ wrote:

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
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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.
--
Cats, coffee, chocolate...vices to live by

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wrote:

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.
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BJ wrote:

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
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BJ wrote:

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
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Palindrome wrote:

[snip] ?
Assuming that the environment continues to maintain quality standards.
Its also useful to review the output of the process a few steps down the road to see if what you had intended is actually what's getting built. Or if something about your design could stand some improvement to get a better product.
--
Paul Hovnanian snipped-for-privacy@hovnanian.com
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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
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... and when you aren't available next time this board has a major spin? Is any of that information (currents, trace frequencies, special grounding requirements) captured in the schematic, preferably in the form of constraints?
Someone previously mentioned that it might be much more efficient for the engineer to layout the board. I strongly suspect it depends on the size and complexity of the board. The layout guys at my employeer (smallish telecom equipment provider) are REALLY good, but the density is such that it still takes them two to three weeks. That's a lot of time the EE could be doing something more productive for the company (like working on FPGA code so that when the board comes back from fab, you can fire the damn thing up!).
Of course, this only works if the layout guys are good. And even if they are, there is stuff you double check anyway. And as others have mentioned, they know the latest on the trade, and the tricks of the trade. It just doesn't seem like a good use of the EE's time to place a couple thousand 0402 resistors. If they need to be someplace special, put a constraint on them. How else will you double check it (even if you did it yourself)?
Marc
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Agreed.
Count yourself lucky. :-)

But how many designs truly have a couple thousand resistors more or less individually positioned? Most such large projects are really just repeating a particular section multiple times, and any decent layout guy will layout a single section and then let his tool automatically group and route the other sections.

Many companies don't have a "flow" that supports the use of constraints. :-(
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I work in power electronics as well. Power supplies are layout critical. One sensitive trace from the control system running under a noisy area and you will NEVER get the supply to work properly with that layout.
I have a layout department at my company as well. If the layout is critical - either do it youself or do a lot of hand holding with the layout person to get it right. In my experience, the only way for one person to layout a critical pcb is to have detailed knowledge of the design. That means the design engineer.
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wrote:

In some places with bypass capacitors, I'll try to create some trace to trace capacitance.. Dunno if it helps...
I haven't done trace resistors yet. I'm afraid a squiggly pattern is just more area to get induced currents from nearby power inductors.
D from BC
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wrote:> At this very moment I'm doing a PCB layout for a 1MHz 130Watt

I wouldn't let a layout guy do PCB layout for power electronics, low noise analog, or RF. Anything else I have had good luck with. Trying to document the requirements for switching supplies, inverters, etc.. is just about impossible. Both creepage requirements between different parts... and the big one, _loop area_ of high dI/dt circuits is often lost on layout people.
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