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Re: gEDA-user: PCB Short and solder bridge elements.



Steven Michalske wrote:
> At work we have two elements that we use pretty extensively for  making 
> connections that are rarely configured.
> 
> The first element is basically a surface mount device such as a 0603  
> but are shorted through the middle.  This is useful for filters that  
> might need to be added later on and not needing a 0 Ohm resistor placed.
> It is also useful for placing a sense resistor for current in dev  
> boards, and only add the component when necessary.
> 
> The second element is basically a solder bridge.  This is two pads  
> placed close together without solder mask in between.
> This element I can make, it's relatively trivial
> 
> The first element on the other hand is harder.  I Want to have  separate 
> net names on each side of the element, and not have the  connection 
> checker declare the nets are shorted.
> The workaround i currently use is to draw up using normal 0603 parts  
> and after my design meets DRC and has no shorted nets, I go through  and 
> manually short the elements.
> The dilemma here is that this is not error-proof, it also provides a  
> dilemma when I accidently route a trace between pads on larger parts,  
> think 2512.
> 
> What suggestions can you folks come up with,  is this something that  we 
> should build into PCB,  the ability for an element to have two  pins 
> electrically connected, but be separate nets.

I think both of these are useful.  For the solder bridge, what you 
really want is a keepout layer so you can prevent (or cause a drc error) 
if any traces ever go into the gap.  For the 0 ohm jumper, I think what 
you need is a layer that marks the underlying copper as a resistive 
material.  I guess the question is how to write the drc rules that 
specify that no other copper can touch it.

-Dan


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