Why is this recommended in PCB layout: 2 leads between pads

[atiker26]

Why is the connection recommended as in the first picture?

[WhoKnewKnows]

What gets recommended depends on who is recommending.

The first might be handy in case of a prototype and the engineer wants to sever the trace(s) and solder in modifications.

Assembly shops don't like the second because of the tendency for the solder mask to lift, exposing the traces between the pads. Then solder covers the traces as well as the pads and it appears there is a solder short between pins. Then the assembly shop waists time trying to remove what appears as a solder short, only to find the short is intentional and only solder mask is missing.

The third should probably only be used where enhanced conduction is required. Otherwise, heavier copper attached to pins just makes the pins more difficult to solder. IE higher heat intensity is required to solder heavy copper connected pads in the same time as lighter connected pads.

[qdrives]

I have spend too much time fixing the "shorts" that WhoKnewKnows mentions. So, perfect answer except that the first is not just for prototypes, but the preferred one.

[atiker26]

thanks for your reply