PCB News - 6 important PCB design specifications

1. Thermal pad, for some power devices, including power amplifiers, power supply DCDC, PMU, and other devices, most of them are QFN or similar packaging forms. Often due to heat dissipation considerations, there will be heat dissipation pads on the bottom of the IC. However, for engineers to design, a piece of exposed copper needs to be opened on the top and bttom layers of the PCB board at the same time, and a through hole is used to connect it in this area, so that the heat can be dissipated as quickly as possible. Because in actual product design, heat dissipation issues are becoming more and more important.

   

   
   2. The width of the power line, basic engineers know about this problem, not much description, you can use wiring or drawing copper, basically follow the formula of 40mil carrying 1A, which can be roughly estimated. It is generally best to leave 25% redundancy.
   3, Pin1 indicator symbol, often everyone knows that when doing chip packaging, the position of pin1 is marked with a triangle or circle symbol. But what everyone often overlooks is that this logo should be placed on the outside of the chip package, so that even the placement process is completed. Errors can also be detected during visual inspection of the factory production line. If the mark is inside, once the patch is completed, the visual inspection will not be able to find the problem. The same problem applies to polar devices such as LEDs, diodes, and tantalum capacitors.
   4. For the design with shielding frame, some RCL components should not be too close to the position of the shielding frame. It is easy to cause the problem of tin connection, especially like some power supply networks. At the same time, the device should not be too close to the edge of the board.
   5. For LCD or other FPC connectors, the pad length is longer than the actual pin length by at least 1mm, the main purpose is to increase stability. In many drop tests, there are often problems here.
   6. For the LCD connector, it is not recommended to place any components in the 3mm area around the connector

The above is the introduction of 6 important PCB design specifications. Ipcb also provides PCB manufacturers and PCB manufacturing technology.