Views:27 Author:Site Editor Publish Time: 2021-01-13 Origin:Site
The welding defects produced by PCBA in the production process are not only related to the production process, welding accessories, and materials, but also have a great relationship with the PCBA pad design. So what are the standards for PCBA pad design? As the leading PCB assembly manufacturer in China, Giant offers custom PCB assembly services, will tell you the standard of PCBA pad design.
Standard for custom PCB assembly pad design
1. Pad design of close-pin IC (0.4Pitch/0.5Pitch QFP)
Lay green oil to separate adjacent pads
Theoretical design: 0.4pitch IC, pad width 0.2mm; 0.5pitch IC, pad width 0.25mm.
Actual acceptance: 0.4pitch IC pad width
2. Dip part pad design on the large copper surface
For Dip parts designed on a large copper surface, each layer of copper foil layer Ring pad is designed to be cross-shaped to reduce welding heat loss and improve weldability. (If the current is insufficient, the width of the connection can be enlarged or the bare copper design can be used).
If there is no green paint covering the large copper surface and tin is not applied, at least 3mm wide green paint should be added to the outside of the ring gasket.
3. Width of solder mask
4. Pad design of Chip components
0201 square PAD: A=0.32mm B=0.28mmC=0.18mm (please increase to 0.2mm if space permits)
0402 square PAD: A=0.51mm B=0.48mm C=0.381mm
0603 square PAD: A=0.8mm B=0.76mm C=0.65mm
0805 square PAD: A=1.32mm B=0.8mm C=1.0mm
1206 square PAD: A=1.57mm B=0.97mm C=1.8mm
The above is an introduction to PCBA pad design standards, I hope it will be helpful to everyone.