Specifying QFN Stencils and Solder Layers
When it comes to paste coverage, less is more. I write a lot about things that go wrong with various layouts. Hopefully by doing that, I can help some readers avoid common pitfalls. But I should probably write about more good things to balance them out.Here’s a decent example. Figure 1 shows a good way to specify the solder paste layer for QFN parts. Notice that the center thermal area is segmented to give about 50% paste coverage. This...