Lesson 10/10100%
MODULE 10

SI Simulation Workflow

Master the end-to-end simulation methodology: from requirements definition through pre-layout analysis, IBIS models, S-parameters, to post-layout verification and sign-off.

Learning Objectives

  • Understand the complete SI simulation workflow from concept to verification
  • Know when to use pre-layout vs. post-layout simulation
  • Understand IBIS models and their role in SI simulation
  • Interpret S-parameters and Touchstone file formats
  • Build and analyze a complete channel model
  • Perform eye diagram compliance verification

Signal integrity simulation prevents costly re-spins by identifying problems before fabrication. At modern data rates (10+ Gbps), every PCB trace is a transmission line, every via is a discontinuity, and every millimeter of routing matters. Simulation transforms guesswork into engineering confidence.

Pre-layout simulation explores topologies using ideal transmission lines and IBIS driver models. Quickly iterate on termination strategies, trace lengths, and impedance targets before committing to a physical layout.

IBIS (I/O Buffer Information Specification) provides behavioral models of IC I/O buffers without revealing transistor-level IP. Explore how V-I curves, ramp rates, and package parasitics affect signal waveforms.

S-parameters characterize the frequency-dependent behavior of a linear network. For SI, they describe insertion loss (Sdd21), return loss (Sdd11), and crosstalk. Explore how channel length, loss tangent, and via transitions affect the S-parameter response.

Post-layout simulation uses extracted geometry and S-parameter models to verify the complete channel meets compliance. Combine TX equalization, channel loss, and RX CTLE to predict the eye diagram at the receiver.

Module 10 Complete!

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