Some Basics about PCB Stack-up in Designing
PCB stack-up is a crucial element to determine the EMC performance of an electronic product. A good stack-up can be so helpful in weakening radiation from the loops on the PCB, as well as the cables attached to the board. On the other hand, a poor stack-up will increase the radiation from both of these mechanisms considerably.
Therefore, designers should take some factors into consideration for a good PCB stack-up.
Here are four essential factors that should be taken into board stack-up considerations:
1. Number of layers
2. Number and types of ground used
3. Ordering or sequence of the layers
4. Spacing between the layers
PCB Stack UP
However, engineers usually do not pay much attention to other three factors except the number of layers. Actually, in many cases, the other three factors enjoy equal importance while the fourth factor is sometimes not even known by the PCB designer. In deciding on the number of layers, the following should be considered:
1. Number of signals to be routed and cost
2. Frequency
3. Emission requirements
4. Shielded or unshielded enclosure
5. EMC engineering expertise
Often only the number of signals will be considered. In reality, all the items are of crucial importance and should be taken into consideration equally. If an optimum design is to be achieved in the minimum amount of time and at the lowest cost, EMC engineering expertise is important and cannot be neglected.
