PCB Design Method Based on Signal Integrity Computer Analysis

In the realm of PCB design, creating a board-level signal integrity model is paramount for ensuring the accuracy and practicality of the design process. Unlike traditional methods, the signal integrity model plays a crucial role in determining the success of the design.

SI Model of PCB Design

• SPICE Model

SPICE, a versatile analog circuit simulator, is commonly used in electronic design. It consists of Model Equations and Model Parameters, enhancing analysis efficiency. The accuracy of the SPICE model depends on data accuracy and the applicability of model equations.



• IBIS Model

Initially developed by Intel Corporation, the IBIS model is now an industry standard for digital signal integrity analysis at the PCB board level. It describes I/O units using I/V and V/T tables, offering computational efficiency.

• Verilog-AMS and VHDL-AMS Models

These hardware behavior-level modeling languages are extensions of Verilog and VHDL. While not as widely supported as SPICE and IBIS, they provide comparable accuracy in signal integrity analysis.

Model Selection

Integrating various models is crucial for high-speed digital PCB design to accurately represent transmission characteristics of critical signals. For passive components, utilizing manufacturer-provided SPICE models or establishing simplified models through experimental measurements are viable options.

Important Considerations for PCB Design

When designing digital integrated circuits, it is crucial to utilize the manufacturer-provided IBIS model. This ensures accurate simulation and analysis of the circuit’s behavior. Nowadays, most IC designers and manufacturers make these IBIS models readily available on their websites or other platforms.

Choosing the Right IBIS Model

For non-critical integrated circuits, if the manufacturer’s IBIS model is not accessible, you can opt for a similar or default IBIS model based on the functions of the chip pins. Another option is to create a simplified IBIS model by conducting experimental measurements.

Transmission Line Analysis

When dealing with PCB board transmission lines, it is advisable to employ a simplified transmission line SPICE model for preliminary signal integrity analysis and space optimization. However, for a comprehensive post-layout analysis aligned with the actual design, a complete transmission line SPICE model is indispensable.