How do you design these days?
in [Design]
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From: krw on 31 Dec 2009 14:12 On Thu, 31 Dec 2009 10:25:48 -0800, Joerg <invalid(a)invalid.invalid> wrote: >Joel Koltner wrote: >> "Joerg" <invalid(a)invalid.invalid> wrote in message >> news:7q2g2rF86cU1(a)mid.individual.net... >>> In the professional world (product design) we go straight from >>> simulation to schematic -> layout -> board fab -> assembly. No >>> breadboards. >> >> Oh come on, even you occasionally dead bug-up (or otherwise prototype) a >> tricky circuit that's part of a bigger product, right? >> > >I do, but much less frequently than a decade ago. I recently thought >about adding a hot air station but when thinking harder I realized that >I would use it way too little to justify the desk space it'll take. > > >> John Larkin does it plenty! :-) >> > >But he has tons of lab space. Heck, they've even got a crane in the lab. >For lifting heavy equipment and transformers around all I've got is >Ibuprofen, in case back pain creeps up :-) We have even better, a technician. ;-)
From: Joerg on 31 Dec 2009 14:27 krw wrote: > On Thu, 31 Dec 2009 10:25:48 -0800, Joerg <invalid(a)invalid.invalid> > wrote: > >> Joel Koltner wrote: >>> "Joerg" <invalid(a)invalid.invalid> wrote in message >>> news:7q2g2rF86cU1(a)mid.individual.net... >>>> In the professional world (product design) we go straight from >>>> simulation to schematic -> layout -> board fab -> assembly. No >>>> breadboards. >>> Oh come on, even you occasionally dead bug-up (or otherwise prototype) a >>> tricky circuit that's part of a bigger product, right? >>> >> I do, but much less frequently than a decade ago. I recently thought >> about adding a hot air station but when thinking harder I realized that >> I would use it way too little to justify the desk space it'll take. >> >> >>> John Larkin does it plenty! :-) >>> >> But he has tons of lab space. Heck, they've even got a crane in the lab. >> For lifting heavy equipment and transformers around all I've got is >> Ibuprofen, in case back pain creeps up :-) > > We have even better, a technician. ;-) If CA was a bit less onerous with rules and regs and taxes I might as well. But ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 31 Dec 2009 14:49 John Larkin wrote: > On Wed, 30 Dec 2009 20:02:02 -0800, D from BC > <myrealaddress(a)comic.com> wrote: > >> On Wed, 30 Dec 2009 20:01:39 -0600, "RogerN" <regor(a)midwest.net> >> wrote: >> >>> When I was in school components fit on solderless breadboards and we made >>> circuits using breadboards, power supplies, meters and oscilloscopes. Many >>> of today's components don't appear to be breadboard friendly, so how is it >>> done today? >>> >>> Is circuit design software and simulation good enough to go straight to a PC >>> board? Or do you use surface mount to breadboard adapters? Do you still >>> use a soldering Iron to solder or paste solder and an oven? >>> >>> I'm wanting to tinker with some circuits but some chips I'm interested in >>> only comes in MSOP or other packages that look intimidating to attempt to >>> solder. >>> >>> Thanks! >>> >>> RogerN >>> >> My motto: >> If it works on a breadboard, it's not worth producing. >> >> On my current project, I have to feed the simulator pcb parasitics and >> component parasistics to get accurate simulations. >> I've had to bench test to get some parasitics. Once parasitics are >> included, scope results and simulation results get close. >> >> If all looks good on sim, I make a pcb, etch it and bench test it. > > One problem is that device models often aren't available for fast > parts, or all you get are S-params when you need large-signal > time-domain stuff. So sometimes you can learn a lot by hacking some > FR4 and testing parts. > > I never breadboard entire products, or even complex circuits... just > enough to characterize parts or simple subcircuits. > > This is an EL07 driving a PHEMT... > > ftp://jjlarkin.lmi.net/BB_fast.JPG > > which made decent 5-volt, 1 GHz square waves. > How do you get those nice clean cuts into the copper? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Phil Hobbs on 31 Dec 2009 15:02 On 12/30/2009 9:20 PM, Joerg wrote: > RogerN wrote: >> When I was in school components fit on solderless breadboards and we >> made circuits using breadboards, power supplies, meters and >> oscilloscopes. Many of today's components don't appear to be >> breadboard friendly, so how is it done today? >> > > I even used bare thumbtacks on plywood for solder posts back then. > > >> Is circuit design software and simulation good enough to go straight >> to a PC board? Or do you use surface mount to breadboard adapters? Do >> you still use a soldering Iron to solder or paste solder and an oven? >> > > In the professional world (product design) we go straight from > simulation to schematic -> layout -> board fab -> assembly. No breadboards. > > >> I'm wanting to tinker with some circuits but some chips I'm interested >> in only comes in MSOP or other packages that look intimidating to >> attempt to solder. >> > > Well, for hobbyists or one-off designs there is help but not very cheap: > > http://www.proto-advantage.com/store/images/PRODUCTS/PA0027_0.JPG > > This is the variety they have but I don't know this shop, just meant as > an example: > > http://www.proto-advantage.com/store/index.php?cPath=2200 > _THE_ professional world? Joerg, Joerg, you've been holed up in that mountain lair of yours for too long. ;) Simulate the parts that simulators get right, do the rote stuff by rote, but prototype the stuff you're not sure will work. It's amazing the amount of stuff you can learn in a short time from a dead-bug prototype. If you're just talking about laying out boards for circuit prototypes, then I agree--you might as well try a bit harder and get it right the first time. But trying out weird stuff, especially in mixed-technology systems, really needs prototypes. Besides, lots of my protos are actually small instruments that I build in half a day and then use for years. An example is the sub-Poissonian current source and LNA I built for my tunnel junction work--very specific, worked great for years, took a day all told to design and build. Good medicine. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: nuny on 31 Dec 2009 15:18
On Dec 31, 8:10 am, Don Lancaster <d...(a)tinaja.com> wrote: > John Larkin wrote: > > On Thu, 31 Dec 2009 14:01:44 -0000, "markp" <map.nos...(a)f2s.com> > > wrote: > > >> "RogerN" <re...(a)midwest.net> wrote in message > >>news:ROudnXLvg9-Tm6HWnZ2dnUVZ_oidnZ2d(a)earthlink.com... > >>> When I was in school components fit on solderless breadboards and we made > >>> circuits using breadboards, power supplies, meters and oscilloscopes. > >>> Many of today's components don't appear to be breadboard friendly, so how > >>> is it done today? > > >>> Is circuit design software and simulation good enough to go straight to a > >>> PC board? Or do you use surface mount to breadboard adapters? Do you > >>> still use a soldering Iron to solder or paste solder and an oven? > > >>> I'm wanting to tinker with some circuits but some chips I'm interested in > >>> only comes in MSOP or other packages that look intimidating to attempt to > >>> solder. > > >>> Thanks! > > >>> RogerN > > >> I tend to design a PCB with CAD software then have prototype PCBs made.. > >> There are several companies out there who do 'pooling', i.e. they amalgamate > >> many designs onto one PCB, that way you end up only paying a small fraction > >> of the tooling cost of the PCB. Some companies can handle 6 layer boards > >> with this process. Example in the UK is PCB Snap from Spirit Circuits > >> (www.spiritcircuits.com). > > >> This can be quite cost effectve for producing protptypes that are as close > >> to the final product as practicable. > > > Why not go for the real thing, first time? If you get it right, you > > can sell it. > > > John > > It is NEVER right the first time. You're getting a bunch of replies from naysayers who have gotten it "right" the first time, but AFAICT mostly from people who have done projects or one-offs. In the world of production though, that's the exception rather than the rule IME. Even if the circuit does exactly what you first daydreamed it could do without a single glitch, even if whoever etches the board doesn't wire a pot backwards (I've had that happen), at some point in the product development cycle somebody will alter a spec just enough so that just enough redesign is required that your baby needs Frankensteining. It might be you didn't include enough LEDs for the required "ooh, shiney" level, the case design asshat^H^Hartists decided the air vents are in the wrong places, it has to go "boop" instead of "beep" when junior feeds it a PB&J, or whatever. SOMEBODY will find a reason it needs "fixing". Mark L. Fergerson |