good walk through ... but if this was a board layout class I would like to start more with theory or at least philosophy / design guidelines, industry standards, checklists etc ... gets back to whether this class is about LED's or PWB's -- I think you are touching on or alluding to the right issues as you go along ...
pad size can matter for some manufacturing houses or even in general. Surface mount in particular but even in through hole boards, over sizing a pad too much may mean the pad becomes a heat sink and the solder joints are less than desired. I have had some occasions where plastic packages have been thought to take on moisture, and the reflow process for surface mount does not get the pads or leads up to temperature specs and bad solder joints occur. Some IC manufacturers warn against this ...
there are checklists online and often from your prototype house that help in layout not only for good design practices, but for manufacturability (DFM) / assembly and to take into consideration testability
@Tenacious, anything Linux will compile and run on Mac, just might not have pretty buttons. I am totally cool with that, in fact I prefer commandline input, even with GUI programs---I find it easier to type Ctrl-C/Ctrl-V than hunt menus with mouse. Want my program compiled? Generate a new set of Gerbers/RS274? I type 'make' :)
@Carol, slide 6 from the first day says 'The HV9910DB3v.3 can supply a maximum output current of 900mA to drive LED strings from a 9VDC to 30VDC input.' I think you're right that the demo board has a 35V cap on input which limits Vin. Just checking.
@jenriquez, You can actually import any board outline shape, including cutouts. Or you can draw it, and right click, change shape type to board outline, and that's it. This is much easier in DesignSpark than Eagle.
@Tenacious Yes it's getting better. I've played with some open source programs for solid modelling and they're pretty good, But hard core technical programs or custom technical programs to control particular machines tend to be PC only.
On Linux a lot of Windows software simply works via Wine emulator. LTspice is a glorious example: Mike Engelhart makes sure (i.e. tests) under Wine, but a lot of other software installs and works just fine. I haven't checked DesignSpark but I will.
@Tenacious I would check with your board manufacturer to see what their routing tolerances are and see if that's good enough for your application. Holes and slots may be different tolerance again. And be careful if it is size or alignment that is more critical.
Carol, this may be more of a question for tomorrow... when specifying the dimensions for your finished board, what is the correct way to specify the mechanical tolerances of the routed edge? I need a board to fit into a very difficult holding slot in a case.
Apologies if it was covered and I missed it but what is the range of input voltages to the HV9910? One of the slides implied that it takes up to 260V so it could be fed from rectified worldwide AC, but another slide listed Vin max 60V
Listen; the issue is not about whether I have OpenOffice or not; the issue is that the Powerpoint format of the slide document generates errors if you open it in anything OTHER than Powerpoint. we should have a document in the correct format to open it flawlessly in whatever we chose to use.
Anyone else notice that the DN Audio bar (above Carol's picture) has a different appearance today? Whenever the red progress bar reaches the right edge, the audio starts buffering, the puase icon appears and I have to manually click on it to restart the audio.
I have used PCAD, OrCAD, PADS (my all time favorite) plus a few others long out of business. Currently use Utiliboard at work and Eagle at home. Designspark looks interesting, but I am always worried about long term support/availability. I have a bunch of boards I can no longer update because the CAD package is no longer available/supported.
I was a bit disappointed in yesterday's class... I would have prefered a general purpose "Approaches to using PCB design software". It is lousy to have a class on such specific PCB Design Software that is PC only when you could have one on Eagle, which is more widely used and cross-platform.
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