gEDA-user: bending design rules for TSSOP20 -- need advice

[Dave N6NZ <n6nz@xxxxxxxx>]

Thought I just saw a thread on this topic, but I deleted the whole works 
and can't find it in the archives.

I'm trying to reconcile a data sheet for a TSSOP-20, 0.65mm lead pitch 
package with PCBexpress's design rules.  The problem: 26mil l.p. and 
10mil pad width leaves 16mil btw pads.  The rule: "8mil between mask and 
copper" leaves exactly 0 mils of mask between pins.

So.... can I bend something here and get a reasonable board?  Something 
like: go to an 8mil pad width so that I get 2mil of mask in between. 
Pad is too skinny, but I guessing should reflow well... those of you 
with more experience than me at SMT need to clue me up.  Will 2mil of 
mask be too skinny to work well? Other option: live with no mask between 
pins and hope I don't bridge.

Thoughts?

-dave


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