Test Pad

[JohnsonMiller]

Hi Guys,

I am wondering when we ask PCB manufacturer to do electrical test, how they actually find the test points? Is this true: any SMD or TH pad will be test point? Or we need to define test points explicitly?

Best,

[robertferanec]

Very important - Always do Electrical testing!
PS: They use pads - they do not need any special testpoints. They need to test every single track anyway - you would not be able to put there so many testpoints.

[JohnsonMiller]

Thank you Robert,
I saw a design in which a rule was added to define each PAD as test point, so I got this question, do we need to define such a rule or PCB manufacturer can extract test points from design?

[robertferanec]

You do not need to do anything. PCB manufacturer can design the test procedure based on gerbers (or other data files what you sent them to manufacture your PCB e.g. ODB++). For testing, they like ODB++ (because it has more information), but gerbers are just fine.

[Paul van Avesaath]

Thank you Robert,
I saw a design in which a rule was added to define each PAD as test point, so I got this question, do we need to define such a rule or PCB manufacturer can extract test points from design?

if you mean a testpad like in the image, that is different to what robert means.. electrical testing is checking the bare PCB (so basically your netlist becomes the test verctor) if you add test points yourself it could be you want testbead to be made to your specific test points. so after assembly you can program and validate your board in the production line. (I do this for our high end products) a testbead like the ones i am describing are around 10K in cost and another 15-20K in software development.. and most projects don't need this stuf..

[JohnsonMiller]

No, I do not mean test point after assembly and debug time. My question is about Electrical Test (Flying Probe) and test point for PCB manufacturing time.

[Paul van Avesaath]

then you do not have to do anything.. the PCB manufacturer gets that from the gerber / ODB++ file