??? 07/20/11 14:22 Read: times |
#182931 - Narrow Gap Responding to: ???'s previous message |
Satish Munot said:
Hi
I think the strength of inner conductor is week (sp. weak) & aera (sp. area) is also Small for inner conductor. Regards Satish Your image as: is showing a gap clearance size that is about about 20% of your line width. For good quality vendors that can etch to 7 mils clearances reliably this means that the corresponding line widths would be 40 mils on your circuit board!! I suspect that if you are actually trying to use more realistic line widths of 15 to 18 mils that your low cost PCB vendor (the one that hand drills the holes) will have great trouble etching your pad design in reliable manner when you come there with a gap dimension in the range of 3 to 3.6 mils. Expect to find many of the "jumper pads" connected due to inadequate etching during manufacturing. Michael Karas PS. In any pattern you use you have to make the features large enough so that you meet the minimum line width for the board fab shop. In my proposed pad design as: you can choose to scale up the size of the feature till the center round pad meets your definition of minimum size required to stay adhered properly to the base laminate material. Michael Karas |