@Thinking_J Schematics? a lousy method to define all the aspects of a circuit being made on a planar surface
There was a time when the pcb layout designer would read the hand-drawn schematic from the circuit designer and proceed with the tape-up.
Then the system was 'improved' with CAD tools. We still drew schematics by hand, but created a netlist by hanging the D-size blueprints on the walls and ran around with yellow markers calling out nets and pin numbers for a scribe to write down. The pcb designer used this netlist to design the layout. I was shocked when learning this system and told that the pcb designer never even looked at the schematic, so there was no point placing notes on it as was my habit.
Then things got worse as the schematic tools became software driven - proved many times the old adage that "to really foul things up you need a computer". (Fortunately things have improved since.)
Better schematic tools allowed the circuit designer to specify trace widths for particular nets, but could not distinguish between the main current-carrying bus and a tap to an IC power pin. You are right - the schematic shows how something is supposed to work, and translation into a properly-designed pcb takes skilled effort - not an autorouter. But it's the onlly tool we got.
@Max: As you have mentioned: "...Another reason is that layout designers are starting to retire, and not many young folks are stepping forward to take their place..."
I agree with what you have said. Many layout engineers are retiring or about to retire but not many young engineers are showing interest to enter this field. As the designs are getting complex and compact, shall we get enough skilled layout engineers in future? Not sure. But will the design engineers would like to do that job? I am pretty sure not many would be interested, if given a choice.
Being a design engineer I have a great admiration of my layout designer friends as I consider thia job requiring lots of patience and yet repeating in nature...not very rewarding. PCB design is not fun unless I am making something for myself (I love designing my own board if I have time and making it for myself) and not while working for others. For a complex 12 layer (or more), I am sure the design engineer would require a layout engineer to work with him/her as there would be a lots of time spent and dedication needed on that layout, which the design engineer can't afford to spend that time/efforts. Hence the demand of layout engineers would remain almost the same.
But the question is, shall there be skilled layout designers left out after a decade? An interesting trend I could see is that layout engineers are getting themselves trained in EMI/EMC, Signal Integrity and other design fundamentals so that they are capable of understanding the design criticalities. This helps them to have a knowledge of what they are doing and sometimes they are mentoring the new younger engineers too about the possible challenges in the design and providing solution; they are also actively participating in the design & review discussions...a possible motivating factors?
Tools will continue to evolve. But I don't see them as a replacement for knowledgable designers)
Schematics? a lousy method to define all the aspects of a circuit being made on a planar surface (FR4, Teflon, ceramic, etc..). Schematics are to convey infomation about the operation of the circuit to others. Sure, it can create a connection list (net list) .. but a simple text file can convey this directly. No, a schematic graphically informs other engineers, techicians HOW the circuit works.
For most of us.. it is the only tool we have... so it becomes a "catch all" for informing the pcb designer how we want the board to be laid out. A bad plan.
This is the reason why:
- Good EEs learn pcb layout tools and manufacturing requirments. Even if they don't become proficent in these other areas, it will help them create optimum work flows within their teams.
- Good PCB designers know something about physics and EE design. (besides manufacturing and layout tools. It is requirement to do their work well.
And why the schematic shouldn't tell the pcb designer ...where to place de-coupling caps. A good pcb designer should already know.
I've seen the future, and it is us. The new Mentor Graphics Sketch Router is a significant improvement on what has come before, but it still relies on the massively parallel processor of the human brain to make it work in tough jobs. If you put a peg in the ground and say "This is as far as technology goes" then auto routers will catch up eventually and board designers will become floor sweeping janitors. However the technology keeps changing, morphing into ever newer combinations of ever newer chip technologies to provide ever newer functionality to ever newer devices at both consumer and professional levels.
During idle time waiting for a transistor post trades course in 1969, I read an EDN article that stated unequivocally that printed circuit boards will become so simple that all they will need to do is provide power, ground and input/output connections because all the smarts are going to be encapsulated in complex silicon. I was impressed, until I saw the real world of discretes becoming simple ICs becoming complex ICs becoming Large Scale Integration becoming Very Large Scale Integration and so on. Board interconnects became exponentially more complex as chips became more complex. Add serious signal integrity issues as rise and fall times became ever faster, and you have a perfect storm of a parallel processing human brain using complex serial tools to solve almost insurmountable interconnect problems.
I believe board designers are not going to go away any time soon. They'll just transform themselves into ever-evolving experts.
And will qualified EEs take over routing boards because of their 'expert' knowledge? I doubt it – I don't know a single EE that knows what he's doing wanting to replace his delight in designing complex schematics to then take on the mundane business of 'connecting the dots', all the while being aware of the myriad fabrication and assembly issues that separate the men form the wannabes. I'm currently working in an area that is at a cutting edge in High Frequency Trading, with some really smart (and young) engineers that have a seriously tight grip on technology. At age 66 I'm a big part of the team, and we work together with individual skills that add huge synergy to making complex designs work. I suspect it will be ever thus.
There, my two cents worth.
Andy Kowalewski, board designer for 34 years, grey hair, working long hours, still loving every bit of it.
Just the physical arrangement ( "layout" ) of wiring on PCBs ( to minimize lengths, bends, stubs, separation of signal from PWR / GND, the no. of layers etc. ) was adequate at lower speeds, but not any more. As the speed of inter-chip communication through the wiring on PCBs rise, the electrical performance ( propagation delay, SSN, RF, SI , ,.. ) of those wiring on PCBs become ever more critical. For wiring ( interconnect ) at the die level ( between transistors, between functional blocks ) CAD has been dominant for many nodes now, the same happened to fine - pitch PCBs ( organic Substrates ) about 15 years ago and is now true for high - end PCBs too. People who do these things are changing accordingly.
I have done a lot of my own layouts, starting with tape many years ago and using many different CAD programs. I have also had layout specialists reporting to me and used independent consultants for layout.
It has been my observation that the best PCB designers are really artists. They see thing I can't like the best placement and ways to route that last difficult trace. Generally they don't know the critical points of a design such as high speed, high voltage, high current or noise sensitive parts of the circuit. The design engineer needs to work closely with the board designer on these areas. In many cases I have sat next to the PCB designer as he did these areas.
Another area the dedicated PCB designer has an advantage is the knowledge of the tools. They will have skills that those of us who do a board every 4-5 months don't. I keep a cheat sheet of tricks so I don't have to figure them out every time, but that is only a stop gap. A dedicated PCB designer will be able to crank out a board much quicker than I can.
There are times when the circuit designer doing the layout is fine, and times when a dedicated layout person will be faster and better.
@Antedeluvian: I think that the requirements for PCB designers have changed, and I do hope (for my sake if not theirs) that the profession can adapt.
I agree -- for the simpler boards it may still be the case that layout designers can get by treating the components as black boxes -- but as designs increase in complexity they have to become much more knowledgable about the components and the underlying electrical aspects of everything.
@Charles: I'm not talking about autorouting, rather tools in the interactive environment that enable user control, quality and performance.
I have to say that the Sketch Routing feature in Mentor's latest offering pretty much blew me away -- the one where you use the mouse to draw a vague "swoosh" that both indicates the traces you are talking about and the general way in which you wish them to be routed ... and the system takes over and does it -- very impressive...
>> I agree -- you can't have one without the other.
Actually, thinking about it, that's not strictly true -- you can't have the layout design without first having the circuit design -- but you can have the circuit design without having a layout design ... you just look rather silly :-)
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