Issue link: https://resources.pcb.cadence.com/i/1310899
www.cadence.com 3 Sigrity SPEED2000 An important advantage of using the combination of Sigrity SPEED2000 and SystemSI technologies is that you do not need to generate S-parameter models for interconnect models, so you can avoid typical non-passive and non-causal problems when S-parameters are used in SPICE time-domain simulation. Those problems are typically more pronounced when a large number of DDR signals is included in the simulation, along with DDR power and ground nets and large number of decaps. Using the Layout Association (FDTD-direct) workflow, you can run what-if DDR simulations to see the impact of non-ideal power/ground on the memory interface design. Figure 4: Sigrity SPEED2000 workflow setup for FDTD-direct simulation from Sigrity SystemSI tool Figure 6: Power-aware simulation results from the FDTD-direct workflow ESD Workflow The electro-static discharge (ESD) workflow is used to test the impact of sudden and unexpected flow of electricity from an external source such as human contact or plugging in a cable with a charge. The flow includes defining the placement of an ESD gun model and then observing the impact to the board, signals, and planes. Transient-voltage- suppression (TVS) diodes and their ability to clamp the voltage peak are included in the ESD simulation. Figure 7: Sigrity SPEED2000 workflow setup for ESD Simulation Using the Sigrity SPEED2000 Engine as a General-Purpose SI/PI Tool The Sigrity SPEED2000 engine offers other workflows and features that make it useful as a general-purpose SI/PI tool: • The power ground noise simulation workflow can be used in direct time-domain power/ground noise simulation for I/O power supply. As an alternative to the Sigrity SPEED2000 tool, one could extract S-parameter models and use them in SPICE simulation. However, since I/O power supply models normally contain many early identical ports for the same power or ground nets, it can be extremely difficult to run simulation in time-domain using a SPICE simulation engine. Using the Sigrity SPEED2000 tool, you can get stable simulation results that would otherwise be very hard to obtain. • The virtual scope—TDR/TDT workflow is a handy feature for evaluating impedance discontinuities in a PCB design. It is especially useful when you want to evaluate impedance discontinuities due to reference discon- tinuities and vias. • The EMI simulation workflow enables you to run simulation using device models with correct stimulus to represent the EMI sources. Figure 5: Sigrity SystemSI tool with a Sigrity SPEED2000 PCB block to be used in the FDTD-direct simulation