Altium: Solder Layer in Footprint Design for HBCC16 / SOT639-2

[allsey87]

Hey all,

I'm currently creating a **broken link removed** in Altium for the ISP1105 USB Transceiver.

Since there is no match in the IPC or component wizards, I'm using the LCC wizard to make the base design before modifying it to be compliant with the specs in the PDF.

Looking at the attached image, you can see that the Top Solder Layer shows rectangular regions overlapping - does this mean that I would have a short circuit if I tried to manufacture this?



Pardon my ignorance, my university didn't seem to consider PCB design and routing an important skill for electronics engineering :???:

Thanks for your time,

Mike

 

[keith1200rs]

I assume you have the solder paste mask to be oversize compared to the pads. As you have spotted, that will be a problem. I think the solder mask needs to be the same size as the pads. There is a discussion about it here: https://www.edaboard.com/threads/136262/

My component libraries don't have any oversize on the solder paste mask - they are the same size as the pads.

Keith.

 

[allsey87]

Thanks Keith,

Regarding the solder mask expansion, does it matter that the top solder mask (not solder paste) from two pads touch?

Cheers, Mike.

 

[keith1200rs]

For the solder mask to work there has to be solder mask between pads. So, while you might expand it slightly on large pads, you cannot do so with fine pitch devices. It might be worthwhile checking with your PCB manufacturer.

Keith