PCB Design Tips For Surface Mount Components
Your first electronic project may involve through-hole components because they are easy to install and solder by hand. But when you make your first commercial design, you are likely to start using surface-mount components, since SMT or surface mount components are less expensive to produce and assemble.
If you are unfamiliar with the design of surface mount components, here are some helpful tips.
Ensure the Right Solder Pad Size
This may be the common sense, but it is worth pointing out that the pad size should be designed according to the recommended pad size in the datasheet. If no reference is provided, the pad size should extend from the SMD component leads to allow the solder to hold. If there is no margin in the pad size, you will find that there are many non-contiguous connections between the surface-mounted component and the pad.
Place SMD Components on One Side
If you do not fabricate PCB in volume, you may need to save template setup costs. If you use SMD components to fill both sides of the PCB, you have to pay for two stencils. However, if you can place all the SMD components on one side of the PCB, you can reduce the cost of the stencil by half. This may also shorten the PCB assembly time.
Make Sure the Solder Paste Size is Correct
When use SMD components in your design, you need to understand how they are assembled on the PCB. Apply a layer of solder paste to the pads before the machine picks up and places the SMD components on the specified footprint. This is done through the opening on the stencils determined by the solder paste mask. Unless the datasheet states, make sure the solder paste opening is equal to or slightly larger than the SMD pad size.