Layers on a PCB

Community PCB Design
1

Hello,

I am doing a little internal PCB (not for customers) which just has a MAX232 to go from RS232 to UART.

Is it true that if one has a PCB with only surface mount components…

…then only the following layers are required in the gerbers…

top copper

bottom copper

top silkscreen

top solder resist

bottom solder resist

top solder paste

bottom solder paste

On the other hand , if some through-hole components are included, then i must put in the Solder mask layer too…becasue thru-hole components get wave soldered, as opposed to surface mount components , that get reflow soldered?

2

You don’t need the solder paste gerbers if you aren’t getting a stencil made. Some board houses will also want an outline gerber; others are OK with the outline on the individual layers. If the SMT parts are on both sides, you may also want the bottom silkscreen.

/mike

3

Thanks Mike,

by the way, is a stencil what you get made only if you are going to get a large quantity of PCBs etched?

4

They are often required for prototypes, if you are getting someone else to assemble them for you. They are mandatory if the board includes BGAs. PCB-Pool supplies a free stencil with all prototypes.

5

A stencil is only used if you are using solder paste. You can also apply paste with a syringe, but as you say, that gets tiring after a few boards.

/mike