For the same device, it is easier to pass the EMC test with SMD electronic components than with dual in-line components. In addition, the antenna effect is also related to the working current loop of each chip. To weaken the antenna effect, in addition to reducing the package size, the size of the operating current loop, the operating frequency and di/dt should also be reduced as much as possible. Pay attention to the pin layout of the latest models of IC chips (especially single-chips), and you will find that most of them have abandoned the traditional way-the lower left corner is GND and the upper right corner is VCC, and the VCC and GND are arranged in adjacent positions to reduce Small working current loop size.
Not only IC chips, but also resistor and capacitor packaging are related to EMC. The 0805 package has better EMC performance than the 1206 package, and the 0603 package has better EMC performance than the 0805 package. The 0603 package is currently popular internationally. Part package refers to the appearance and location of solder joints indicated when the actual part is soldered to the circuit board. It is a pure space concept. Therefore, different components can share the same part package, and the same kind of components can also have different parts package.
Like resistors, there is a traditional pin-insertion type. This type of component is large, and the circuit board must be drilled to install the component. After the drilling is completed, the component is inserted, and then the tin furnace or spray tin (also available for hand soldering) costs more High, newer designs use small surface mount components (SMD). This type of component does not need to be drilled. Use a steel film to pour semi-molten solder paste into the circuit board, and then put the SMD component on it. Solder on the circuit board.