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Type: Posts; User: marce

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    Closed: Re: PCB design 450 MHz LVDS trace routing

    100r diff is not alway equal to two 50r SE lines, depends on PCB geometry. Skew is the most important factor according to Howard Johnson and a couple of others.
  2. Closed: Re: What is meant by "coating" when PCB track spacing is concerned?

    Drain and source will be at the same voltage when the device is on...
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    Closed: Re: PCB design 450 MHz LVDS trace routing

    Agree, most are 90-100, PCIe goes down to 85, but cant find any at 80... so I would aim for a 100 or get the spec for the interface you are laying out and READ IT.
  4. Closed: Re: Vias covered in solder resist get outgassing problems?

    Don't need to go to NASA or ESA levels in reality...
    To be honest out-gassing is an old issue, very few boards suffer from it today. There has been a previous long thread on this, in fact probably...
  5. Closed: Re: Understanding vibration resistance specification impact on HW design

    There is a mil spec that covers how much weight is allowed per pin for vibration, I cant remember the figure and can't find my specification at the moment..
    Component shape and dimensions can give a...
  6. Closed: Re: Vias covered in solder resist get outgassing problems?

    Some cover vias, some don't can't say I have noticed any difference these days...
    I think there may be some confusion regarding the use of liquid photo imageable solder resist. I would ask them to...
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    Closed: Re: Rigid flex Cross section OrCAD PCB Designer

    Components go on rigid PCB sections not the flex layers....
  8. Closed: Re: Gerbers and drills offset from one another...cant view properly in GC prevue

    Set the default to bottom left of the design for both gerber and excellon, then it will also line up with the IPC-D-356 data if you use it.
    It is not a bug, Excellon2 data only contains the drill...
  9. Closed: Re: PIC16F1947 land pattern doesnt tell of solder resist "stencil"

    Use IPC-7351 rules, do solder mask same size as the pads, it can then me adjusted to fit the technology level of the PCB during manufacture, in some cases the over size can be zero for solder mask...
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    Closed: Re: I have a question about PCB recycling

    Nope, only the metal is recycled.
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    Closed: Re: Certificate Standard IPC

    Look for IPC CID courses in your area online.
  12. Closed: Re: Passing radiated EMC with an SMPS involves an element of luck...how much agree?

    I've done SMPS's in non metal cases that have passed EMC requirements, care and understanding of the beast is what you need, break it down into little bits and its easier, like all circuits, split it...
  13. Closed: Re: First attempt at USB differential pair routing on a 2 layer board. Acceptable or

    Nope you are providing a RETURN path for all your signals, never a waste, always a benefit...
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    Closed: Re: Thermal vias in pads..plated over

    On critical jobs I have the plating done thicker, 0.035-0.050mm plating in the via... Generally mil/aerospace jobs, cheaper than plating.
  15. Closed: Re: Speakers make a loud noise when turning off. Is there a way I can eliminate it?

    If you are turning off with a mains switch a 0.1uf cap across the switch can often solve the problem, its a common issue when mains is switched directly.
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    Closed: Re: Thermal vias in pads..plated over

    Don't fill them, its cheaper.
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    Closed: Re: Ethernet vs USB discussion and/or comparison

    If you remove the packet overheads its not USB or Ethernet...Your reply is also a bit un-polite shall we say...
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    Closed: Re: COnductive vs Non-Conductive Power Connectors

    This is referring as siad to mil spec connectors, usually D38999 beasties, if your using them for a mil contract, then the finish will be specified, if not pick the one suitable for the design at...
  19. [SOLVED]Closed: Re: I need help understanding measurements / dimention markings on a datasheet

    Better still read the DXF into your cad package and use as a base for the component.
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    Closed: Re: Heatsink soldermask on PCB

    If we fit a heatsink we remove the solder resist even when using thermal pads, but generally just using the PCB we leave the solder mask on...
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    Closed: Re: Heatsink soldermask on PCB

    Have a read of this...
    http://www.ti.com/lit/an/snva183b/snva183b.pdf

    Done both ways...
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    Closed: Re: Fanout of 0.65mm BGA

    Start with filled via in pad...
    Outer rows fan out on mounted layer, inner rows fan out with a 0.1mm track/gap, suppress inner layer pads...
    This is always a useful tome to have handy......
  23. Closed: Re: Convert 20year old CADSTAR(?) .PCB File to Usable format

    Easier just to use cadstar...:grin:
    Data sorted...
  24. Closed: Re: Looking for pcb manufacturers for large boards (31"x17"x0.286" 40 layers)

    Will ask around, I know people who do mixing desks and have the same problem, once you go above their approved panel size your a bit goosed. Its not the PCB material but having the processing...
  25. Closed: Re: Convert 20year old CADSTAR(?) .PCB File to Usable format

    Can probably do it... email me.
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