Select the layer type, its function, and material in the Add Layers dialog box.Right-click the Objects column and choose Add Layers.Adding more layers between the plane layers and placing the signal layers close to the plane layers, increases the interplane capacitance and improves the EMC performance as a result. The loss of interplane capacitance can be compensated by providing tight coupling between signal and plane layers. For example, if there is a large separation between the power and ground planes in a multi-layer design, the interplane capacitance between the adjacent power and ground planes will be insufficient and may not provide adequate decoupling. The number of layers in a stackup is determined by the number of signals to be routed and the operating frequency.Ī design with a poor stackup may lead to failure. It is also an effective way to reduce the radiation from the loops formed on a PCB. Layer sequencing is one of the many factors that determine the performance of a PCB from a signal integrity point of view. We’ll explore more as we move forward in this post. Some of the key layer information that you can specify includes, layer material, thickness, dielectric constant, loss tangent, and so on. To define a useful layer stackup for a PCB design, it is important to first understand what layer information can be added using Cross-section Editor. What Layer Information Can I Specify in Cross-section Editor? The single-stackup mode is the default mode, where all the electrical layers, such as conductor, plane, and dielectric are displayed in the Primary tab.Īlong with the multiple-stackup definitions support for electrical layers, this mode also supports multiple-stackup definitions for non-electrical layers such as soldermask and coverlay, which can be used in rigid, flex, or rigid-flex PCBs. You can enable the multilayer-stackup mode using the View – Multi Stackups mode menu command. Alternatively, use the xsection command.Ĭross-section Editor displays ordered layers of the active design and the attributes of each layer, such as its thickness, material, conductivity, and so on.Ĭross-section Editor provides support for both single-stackup and multilayer-stackup. You can access Cross-section Editor from any Allegro layout editor using the Setup – Cross-section menu command. You can define a layer stackup and specify attributes of each layer in Cross-section Editor. This blog post shows how you can define a multi-layer stackup for rigid and flex PCBs and specify layer information for a design using Cross-section Editor. With Cross-section Editor, defining dielectric and conductor layers and external mask layers for rigid and flex board designs is easier than ever before. Layer information includes the number of layers and the material used for the layers in a stackup, and the attributes of each layer, such as design impedance, layer thickness, and conductivity.
#Allegro change layer item in xsection image plus
The layer stackup also affects cross-talk and net impedance and these two factors, in turn, drive the functional performance of a PCB.Īllegro ® layout editors – Allegro ® PCB Editor and Allegro ® Package Designer Plus – include a spreadsheet-based user interface, Cross-section Editor to help you define an accurate layer stackup with key layer information to avoid any electronic component design failure. An accurate stackup definition is critical to getting the best possible performance from a design. To manufacture a product that performs as you intended, it is imperative that you share accurate stackup definitions with the board fabricator or manufacturer.
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