High speed Designs - Part 5

 To eliminate Signal Integrity issues on the board,

1. Signals must be routed with good impedance control.

Impedance controlled routing is one of the important requirement in the high speed board designs. This involves routing done on the PCB with a single impedance across the board. The reason why impedance control is important is to eliminate the signal integrity issues because of different impedance values. The signals have different trace widths in different layers to achieve the same impedance for the signal in all layers. This need to be adhered to for reliable channel communication.

2. Follow proper design guidelines

Every component we have selected has a datasheet, design guidelines every engineer has to follow during their design. The component vendor would have done a thorough review/analysis before releasing their chip set/component. Follow the recommendations for a successful. Some times you might have to deviate from the guidelines, in such cases it always important to simulate the design before going ahead with the next steps.

3. Simulate the design

Simulation is the most important step in the design to evaluate the performance of the design before taking it to the fabrication. The simulation will be done before as well as after the layout. This helps us to predict and eliminate the signal integrity and power integrity issues that may come on the board. Hyper Lynx is the widely used tool in this scenario.

4. Routing to eliminate EMI/EMC issues

Certification is the most important step for the product. Certification is directly the product performance under various external conditions. In the first we have discussed about the impedance control in PCB routing, on the same lines, there are several other routing guidelines that need to be followed, like for example, routing most of the high frequency signals in in the inner layers with proper reference plane, proper power supply design architecture, careful component selection, eliminating leakages, proper shielding techniques, etc.

We will discuss on the other guidelines in the future articles.