平衡的叠层设计(Designing Balanced Printed Circuit Boards):Designers can be tempted to design printed circuit boards (PCBs) with an odd number of layers.If the additional layer is not needed for routing, why use it? Won’t eliminating the extra layerminimize board thickness? If the board has one less layer, the cost should be lower...shouldn’t it?But, on occasion, adding a layer can help reduce costs.The stackup of layers in the board can be handled in two different ways: core construction orfoil construction (See Figure 1).