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IC PackageTransient Analysis Examples - Digital Signals
General Description
This example shows the calculation of an arbitrary IC package concerning the propagation of digital pulses. It analyses the cross-talk effects of a simultaneous excitation of three adjacent pins with different digital signals and timing delays. The model consists of a silicon chip which is encapsulated within a nonconductive plastic compound. The surface mounted package is soldered to printed circuit board with a PEC ground layer.
Structure Generation
The package is created by boolean and chamfer operations. The pins are defined by means of extruded profiles and multiple transformations. Loft operations are used to model the traces to the silicon chip inside the package. The entire row of pins is then rotated and mirrored. The silicon chip is modelled as a substrate with a ground layer. Finally the printed circuit board is modelled as a substrate with the electric boundary as the ground layer.
Solver Setup
Before the transient solver can be started, the excitation sources have to be defined. To create the discrete ports in an efficient way, a local VBA macro ist used. The macro generates a discrete port between each picked point and the ground layer determined by the z-coordinate of the last picked point. First, ports 1..52 are defined at the pins outside of the package. Then the connections from the metal pin traces to the silicon chip are modelled as bond wires. Ports 101..152 are created with a second macro-call at the ends of the bond wires. To demonstrate the propagation of digital signals ports no. 1, 2 and 3 are excited simultaneously using different rectangular pulse and temporal shifts between the excitation sources.
Post Processing
The obtained time signals of the transient calculation are listed in the navigation tree in the folder 1D Results. Right-click on the Port signals folder and use Select Result Curves... to display the i1, i2 and i3 and o101, o102 and o103 signal only. They demonstrate the resulting deformation of the simultaneously excited digital pulses while propagating in the traces of the IC package. HFSS视频教程 ADS视频教程 CST视频教程 Ansoft Designer 中文教程 |
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