Survey: FPGA PCB layout

[JosephKK]

I agree with Joerg. Good high speed or mixed signal PCB layout is a career
choice, and we electrical engineers already chose our career. A good layout
requires someone who understands not just the software package, but the
details of how the manufacturing operation is going to proceed, what the
limits of the processes are, what the assembly operations require of the
board, and is anal about things like footprint libraries and solder mask
clearances and a thousand other details that I'm only partially aware of.
The more complex your design, the more critical these things become.

I have two good local outfits for farming out boards. For complex stuff,
they know I'll come to their place and sit next to the designer for a good
bit of the initial placement. While we are doing placement, we are also
discussing critical nets, routing paths, layer usage, etc. That gives us
direct face to face communication and avoids spending lots of time trying to
write/draw everything in gory detail (which gets ignored or misunderstood a
lot of the time). That investment pays big dividends in schedule and board
performance.

Don't be fooled by the relatively low cost of the software. That's not where
the big costs are.

I once laid off my entire PCB layout department and sent all the work
outside, because although my employees all knew how to use the software,
none of them could tell me what their completion date would be, or how many
hours it would take, and they certainly weren't interested in meeting
schedules. The outside sources would commit to a cost and a delivery date.
And we already knew they could meet our performance objectives. Fixed price
contracts are great motivators. Missing an engineering test window, or
slipping a production schedule because of a layout delay can be enormously
expensive.

Of course, if I had let my engineers do their own layouts, the motivation
would have been present, but the technical proficiency would not. How
proficient can anyone become if they only do layout a few times a year?
Also, on many projects engineers use the layout period for other important
things like documentation, test procedures, writing test code, etc. Doing
your own layout serializes these tasks and will stretch your schedule.

So my advice is to keep doing what you have been doing. Its far more likely
that its the cheapest approach, even though you occasionally have to write a
big check.

Steve

Pretty much honest responses. Almost all of good value.

Mark hinted and Joerg mentioned one of the foremost subjects,
floorplanning. This will impact everything you do. From the original
schematic drawing to the FPGA VHDL/Verilog coding and optimizing to
PWB layout , documentation, and testing. Each of these activities
requires floorplanning to get good results. To achieve the best PWD
layout results make several different versions for your first few
boards and route them all to completion. It will make huge
improvements in your understanding.

 

[JosephKK]

All I know from here (CA) is that their benefits are mind-boggling.

OK lets get to that.

Paid sick leave,

Not particularly uncommon until you get to low end hourly. Standard
for engineers since WWII.

fat disability payments where lots of people tried and
succeeded to be declared "disabled",

Yes there has been abuses.

cradle-to-grave medical with hardly any co-pay.

When i worked for private as an engineer it was $5 for office visit,
$20 for lab, $5 per prescription. Today with State of CA it is $10 or
more for office visit, $0 for lab, $5 to $25 per prescription. It
increases in retirement. Then Medicare is supposed to kick in and
relieve much of the State burden. If you are 65 or older and don't
like what you have try Medicare and see how well you like that.

The latter alone will saddle our communities with previously
unheard of debt.
Oh, and then lots of jobs have the retirement benefit
tied to the last work year. So, folks have themselves transferred into
high-cost areas such as the Bay Area for 13 months or so, then move
back. That ratchets their monthly checks up substantially, until their
dying day. That ain't right.

It has been changed to the highest paid three years average in the
last ten. And it now takes ten years to become "vested", instead of
five.

Now, you have been reading my stuff for some years now, do you think i
am a doofus parading as an engineer? When i was hired some 15 years
ago a PE could only expect about $5000 a month in State service. What
was your monthly average then. What was it 5 years ago? What is it
today. CA State pay rates for engineers and almost all others is a
matter of public record. Try looking them up for yourself. You would
do well to start with www.spb.ca.gov. Better still, compare them to
County and City rates for the last 20 years. And finally note that
for most cases the State does not give you a better paycheck based on
where the job is, let alone where you live.

80 percent to 90 percent of half to two thirds of what a private
engineer can make ain't all that much. You may get a lower top
percentage, but it is / was based on a much better salary.

 

[JosephKK]

I don't know about "gone". The age of the "defined benefit" is
pretty much gone in private industry but several still have "defined
contribution" plans. Now, 401Ks make up for a lot of what's been
lost and are portable.


Maybe. There are better things to do at 70, though. ;-)

The last years' is indicative of the final salary. Most "defined
benefit" plans do take the last year, or last couple of years into
account. What most private pensions *don't* do, that public plans
do is include overtime in the formula. It's not hard to double
one's income for a couple of years. There is no way the tax payer
should pay that forever.

So you say. While there are classes where that is easily done it is
usually in the mid range hourly and low range salaried that it is
reasonably possible. But how may 50+ year olds do you know that can
and will work significant overtime?

 

[JosephKK]

It's quite normal for a company to add significantly to the 401K,
sometimes with strings attached, sometimes without. My PPOE had a
fairly decent 401K (in addition to pension plans for everyone
joining before '06, or so). They matched 1:1 up to 6% of salary
(plus bonusus) and had no management fees for the normal funds. I
understand it's gotten better since they've dropped the pension
plans for the newbs.


I got quite bored, once I wasn't allowed to make messes at home
anymore. Good thing that only lasted a week or two. ;-)

Precisely. It's not going to get better. The government requires
others to have fully funded retirement plans, but would have none of
it for themselves.

Actually CalPERS is one exception to the slightly over broad brush. Of
course over 2E11 dollars is not a toy.

 

[JosephKK]

Mostly it's a mere pittance. And that's ok, I am a strong believer that
everyone should pull their own weight. Except disabled people, of course.

Actually i have found an amazing amount of them that can do just that.
I expect you have heard of Steven Hawking?

Correct.


True. However, we should embrace the Japanese concept of letting older
folks teach the young ones, not lay them off.

There is a trade off there. You need to limit that to the most
flexible and brightest old personnel.

Just make it the same as with 401(k), IRA, old style pension funds,
social security etc. What counts is what you pay in over your whole career.

Heavily weighted by the early amounts because of compound interest.
Check it out. Moreover, no matter what the contributions were there
should come a point where the interest on the early contributions
outweigh the current contributions. Do the arithmetic. A spreadsheet
program makes this relatively painless.

 

[JosephKK]

I guess it depends on the employer...

Do you see anything bad about the old system of pensions (from private
companies, ignore the government for the moment)? I see them more as
"different" than particularly better or worse. These days you're personally
responsible for more of your retirement planning, which has the upside that
you can probably do a better job than some company-wide pension programs used
to do, but the downside is that those who plan poorly (or not at all) end up
needing that much more government assistance once they're retired.


Yes, agreed 100%.


The end result there is that if your employer requires you to move to, e.g.,
California for the last few years of employment you'll pretty much be forced
to then immediately move when you hit retirement. I suppose that isn't
particularly awful, since that fact would have been clear when the employer
said, "move!"


Sheesh... screw the taxpyers with retiremend funding and then screw'em again
when someone tries to blow the whistle. Nice...

Finally, someone else caught on.

 

[JosephKK]

In Altium Designer I use the incredibly useful "subnet jumper" feature
for BGA's.
The procedure goes something like this:
1) Fan out all the required FPGA pins first (automatically or
manually) to just outside the chip boundry. (leave several diagonal
entry paths for core and other power flood fills to get in)
2) Fully route all non-pin-swappable pins and other critical lines.
3) Ensure any other parts placements are near any required FPGA pins
or block features you think you might need.
4) Route every track just short of the fanout tracks
5) Hit the "add subnet jumper" feature and it finishes the tracks and
does all the pin swaps for you and updates the schematic.

Probably needs a picture or two to explain it best though...

The great part about subnet jumpers is if there are timing or other
problems you can just remove the subnet jumpers and add/edit tracks
and pins as needed and then replace the subnet jumpers. Only takes a
minute or two.

Dave.

That does sound specific to one particular tool (vendors's software).

 

[Joerg]

Actually i have found an amazing amount of them that can do just that.
I expect you have heard of Steven Hawking?

Yes, a remarkable guy. I didn't mean folks who develop Lou Gehrig's
although they will also need support once it has progresed to a point. I
mean people like the guy with Down syndrome we sometimes visit. He's on
disability and that is really the only way for him to live.

There is a trade off there. You need to limit that to the most
flexible and brightest old personnel.

That would be no problem.

Heavily weighted by the early amounts because of compound interest.
Check it out. Moreover, no matter what the contributions were there
should come a point where the interest on the early contributions
outweigh the current contributions. Do the arithmetic. A spreadsheet
program makes this relatively painless.

I don't think we'll see the interest rates of yesteryear anytime soon.
But the point is there should not be preferential treatment of public
service employees on the shoulders of the taxpayer.

 

[Joerg]

OK lets get to that.

Not particularly uncommon until you get to low end hourly. Standard
for engineers since WWII.

Most people I know don't.

Yes there has been abuses.

Big time. I've seen lots of it. People who collected fat checks because
of back injuries and then personally erecting retaining walls and stuff.
IMHO there is an utter lack of enforcement.

Hey, didn't even Spike Helmick try to collect a fat pension "upgrade"
claiming he fell off his armchair?

When i worked for private as an engineer it was $5 for office visit,
$20 for lab, $5 per prescription. Today with State of CA it is $10 or
more for office visit, $0 for lab, $5 to $25 per prescription. It
increases in retirement. Then Medicare is supposed to kick in and
relieve much of the State burden. If you are 65 or older and don't
like what you have try Medicare and see how well you like that.

I must pay $65 for an office visit. Plus the first $2700 (per person!)
per year out of pocket, else the premiums become unbearable. A lot of
engineers I know how no health insurance at all because they can't
afford it any longer.

It has been changed to the highest paid three years average in the
last ten. And it now takes ten years to become "vested", instead of
five.

That's good but still not fair compared to people in non-gvt jobs.

Now, you have been reading my stuff for some years now, do you think i
am a doofus parading as an engineer? When i was hired some 15 years
ago a PE could only expect about $5000 a month in State service. What
was your monthly average then. What was it 5 years ago? What is it
today. CA State pay rates for engineers and almost all others is a
matter of public record. Try looking them up for yourself. You would
do well to start with www.spb.ca.gov. Better still, compare them to
County and City rates for the last 20 years. And finally note that
for most cases the State does not give you a better paycheck based on
where the job is, let alone where you live.

80 percent to 90 percent of half to two thirds of what a private
engineer can make ain't all that much. You may get a lower top
percentage, but it is / was based on a much better salary.

Half? $5k/mo is about what engineers in industry made 15 years ago.

But the real perks are in other jobs where the legislature has caved in
to the unions. Prison guards etc. A while ago the news reported the
staggering number of applications sent in. It may not be a fun job but
it sure must have become a plum job.

 

[Joerg]

So you say. While there are classes where that is easily done it is
usually in the mid range hourly and low range salaried that it is
reasonably possible. But how may 50+ year olds do you know that can
and will work significant overtime?

Plenty around here. Usually in law enforcement.

 

[Joerg]

Pretty much honest responses. Almost all of good value.

Mark hinted and Joerg mentioned one of the foremost subjects,
floorplanning. This will impact everything you do. From the original
schematic drawing to the FPGA VHDL/Verilog coding and optimizing to
PWB layout , documentation, and testing. Each of these activities
requires floorplanning to get good results. To achieve the best PWD
layout results make several different versions for your first few
boards and route them all to completion. It will make huge
improvements in your understanding.

Right. The same goes for code, especially micro controllers. Without
spending a lot of time on a floor plan chances are it won't fit in or
it'll become a hodge-podge of code snippets somehow stitched together.
Seen a lot of that :-(

There seems to be a huge software company up north that has in part lost
the art of good floorplanning ...

 

[krw]

So you say. While there are classes where that is easily done it is
usually in the mid range hourly and low range salaried that it is
reasonably possible. But how may 50+ year olds do you know that can
and will work significant overtime?

Overtime should never be needed in a well run company. That said,
I've been averaging 60hr weeks (some 70+ and a few weeks with
holidays, less) since August and have at least a few more months of
work left on the pile, if I want it. There is no reason a 50s can't
work overtime but there is also no reason to need, want, or expect
it. BTW, I certainly wouldn't be working the overtime were I
salaried.

 

[Joerg]

Overtime should never be needed in a well run company. That said,
I've been averaging 60hr weeks (some 70+ and a few weeks with
holidays, less) since August and have at least a few more months of
work left on the pile, if I want it. There is no reason a 50s can't
work overtime but there is also no reason to need, want, or expect
it. BTW, I certainly wouldn't be working the overtime were I
salaried.

So what do you do at the end of this gig? Maybe buy Adnan Kashoggi's
yacht ;-)

 

[David L. Jones]

That does sound specific to one particular tool (vendors's software).

Yes, it is specific to Altium Designer. It's their way of simplifying
FPGA design and layout.

Dave.

 

[Joerg]

For medical devices/equipment, I'd be concerned with getting an RoHS
waiver and non-green parts and solder, so that the device/equipment
isn't likely to fail in a few years due to tin wiskers and harm the
patient.

Sure. However, about a year ago we learned that we better brace
ourselves for not so good things to come:

http://www.greensupplyline.com/howto/192300282

 

[krw]

So what do you do at the end of this gig? Maybe buy Adnan Kashoggi's
yacht ;-)

Every hour I work now is at least two I don't have to later. ;-)
As they say, "you gotta make hay while the sun is shining".

 

[JosephKK]

Yes, a remarkable guy. I didn't mean folks who develop Lou Gehrig's
although they will also need support once it has progresed to a point. I
mean people like the guy with Down syndrome we sometimes visit. He's on
disability and that is really the only way for him to live.


That would be no problem.


I don't think we'll see the interest rates of yesteryear anytime soon.
But the point is there should not be preferential treatment of public
service employees on the shoulders of the taxpayer.

Preferential? I think not. Civil service employees generally get
what was normal in industry 10 years ago. They usually trade job
security for about a sixth less pay. It is the near invulnerable job
security that is the problem.

 

[JosephKK]

Most people I know don't.



Big time. I've seen lots of it. People who collected fat checks because
of back injuries and then personally erecting retaining walls and stuff.
IMHO there is an utter lack of enforcement.

Hey, didn't even Spike Helmick try to collect a fat pension "upgrade"
claiming he fell off his armchair?



I must pay $65 for an office visit. Plus the first $2700 (per person!)
per year out of pocket, else the premiums become unbearable. A lot of
engineers I know how no health insurance at all because they can't
afford it any longer.



That's good but still not fair compared to people in non-gvt jobs.

Current pay rates are here:

http://www.dpa.ca.gov/publications/pay-scales/index.htm

Please note some of the wild variation in engineer classifications.
For this group we should look for electrical or electronic engineers.
Senior engineer supervises working engineers, supervising engineers
are the bosses of seniors, and they in turn report to principle
engineers.

I have not bothered to find historical pay rates yet. All of my peer
group has made more in private than in public positions. If you are
not doing as well, that is not my problem.

 

[JosephKK]

Right. The same goes for code, especially micro controllers. Without
spending a lot of time on a floor plan chances are it won't fit in or
it'll become a hodge-podge of code snippets somehow stitched together.
Seen a lot of that :-(

There seems to be a huge software company up north that has in part lost
the art of good floorplanning ...

Actually it never had it.

 

[JosephKK]

Sure. However, about a year ago we learned that we better brace
ourselves for not so good things to come:

http://www.greensupplyline.com/howto/192300282

Yep. Volume issues. All the standard parts are RoHS. Then the
questions get asked. Fortunately there are recent 4-element alloys
that have fairly good properties and seem to lack tin whisker
problems. Nothing fully qualified for space / life critical quite
yet, but it is on the horizon.