What are the thermal design structures and requirements of PCBA?

子月丷

What are the thermal design structures and requirements of PCBA? [Copy link]

PCBA will encounter a large temperature difference duringSMTpatch processing, and if this temperature difference exceeds ourPCBAcontrol the temperature difference in theactualSMTPCBAis composed of many parts,each of which has different functional characteristics. The following professional one-stop electronic processing manufacturer Pet Technology will introducePCBA.

1. Heat sink pad

In the PCBA patch welding of heat sink components , the phenomenon of insufficient tin on the heat sink pad will be encountered . This is a typical application situation that can be improved through heat sink design. The design can be carried out by increasing the heat capacity of the heat dissipation hole, connecting the heat dissipation hole to the inner ground layer. If the ground layer is less than 6 layers , a part of the signal layer can be isolated as a heat dissipation layer , and the aperture can be reduced to the minimum available aperture size.

2. High-power grounding jack

In some special PCBA designs , the plug-in holes sometimes need to be connected to multiple ground / electrical plane layers. Since the contact time between the pin and the solder wave during wave soldering is very short, cold solder joints may be formed. In order to avoid this , a design called star-moon hole is often used to separate the soldering hole from the ground / electrical layer , and large current is realized through the power hole.

3. BGA solder joints

Under mixed assembly process conditions , there will be a phenomenon of " shrinkage fracture " caused by unidirectional solidification of solder joints. The fundamental reason for this defect is the characteristics of the mixed assembly process itself . Generally, the PCBA solder joints that shrink and fracture are located at the corners of the BGA . By increasing the heat capacity of the BGA corner solder joints or reducing the heat conduction speed , they can be cooled synchronously or later with other solder joints . This avoids the phenomenon of being pulled apart under the BGA warping stress due to early cooling .

4. Chip component pads

As the size of SMT chip components becomes smaller and smaller , there are more and more phenomena such as displacement, tombstone, and flipping . The occurrence of these phenomena is related to many factors , but the thermal design of the pad is one of the aspects with the greatest impact.

Guangzhou Peite Electronic Technology Co., Ltd., www.gzpeite.com , specializes in one-stop PCBA processing, SMT patch processing, and all-inclusive services.