CadenceAllegroSI培训课件CadenceAllegroSI培训课件Lesson6章节.ppt

Lesson 6 Template Applications and Constraint-Driven Placement,Create topologies in SigXplorer. Differentiate between ideal TLine and trace models. Use various single trace and coupled trace models in SigXplorer simulations. Run Crosstalk simulations in SigXplorer. Apply a topology template (Electrical CSet) to a net or group of nets In the board design. Get information about nets and DRC errors in the board design. Perform constraint-driven placement.,The Allegro PCB SI Design Flow,Pre-Placement Solution Space Analysis Constraint-Driven Floorplanning Constraint-Driven Routing Post-Route DRC Post-Route Analysis,The Allegro PCB SI Design Flow consists of the following six steps:,E,You are Here,Double Click Here to Open the Image,,Adding Trace Models,You can add Lossy Transmission Line models for simulations in SigXplorer Single Conductor Trace Models Microstrip and Stripline Coupled Trace Models Edge Coupled and Broadside Coupled Microstrip and Stripline,Shield layer Dielectric layer,,,TLines and Trace Models,Single line trace model,Coupled line trace model,TLine model,Lossy transmission line models,Transmission lines represent the interconnect. You can modify parameters to control the routed interconnect characteristics.,Coupled TLine model,Ideal transmission line models,,,,,Coupled Traces,Right click over the trace name or one of its values in the Parameters tab of the SigXplorer spreadsheet to display and select the View Trace Parameters pop up menu.,,,You can view the RLGC matrix of the coupled trace model.,RLGC Matrix of Coupled Trace Models,Crosstalk Simulation in SigXplorer,You derive parallelism rules for nets to ensure that the final design is not adversely affected by crosstalk-related problems when developing topologies in SigXplorer.,Simulating with Coupled-Trace Models,Devices = Fast and Slow,Terminators are +/-1ohm,Sweep Simulation Results with Coupled-Trace Models,Receiver on Victim net.,,How Crosstalk is Calculated in SigXplorer,The following features apply to coupled-trace topologies: Crosstalk is calculated using closed form analysis. The crosstalk is measured on the victim net from each aggressor net in the circuit. The reported crosstalk is the result of all the aggressor contributions. Multiple drivers can be active during simulation. Results are reported in mV. There is a maximum of six coupled traces. The following limitations apply to coupled-trace topologies: Topologies containing coupled traces cannot be applied to Allegro PCB SI nets. These topologies are for exploring coupled-trace behaviors and deriving parallelism rules. You derive the parallelism rules and must manually add them to target topologies,Lab: Session 1 Using Coupled Trace Model in SigXplorer Crosstalk Simulations,Lab,Constraint Manager – Key Features,The Constraint Manager is a cross platform, workbook- and worksheet-based, graphical interface application used to manage high-speed electrical constraints across all the tools in the Cadence PCB design flow. It allows the concurrent and independent capture of design constraints in schematics and PCB databases. It offers a common, powerful environment for constraint definition, view, edition, management and verification. It allows hierarchical management of constraints. It supports system-level constraints. It is tightly integrated with design tools. Spreadsheet updates as components are placed or nets are routed. Analysis engines update spreadsheet data interactively. SigXplorer is integrated with the Constraint Manager.,Constraint Manager – Cross Platform,Constraint Manager – Object Hierarchy,Inherited,,Overrides,,15,Constraint Manager – Workbook and Worksheet,Holds all the ECSets and their constraint values in the database.,,,Holds custom measurement data in the ECSet.,Holds different nets in the design, names of the ECSets assigned to the nets (if any), constraint values associated with the nets.,,Select Setup Electrical Constraint Spreadsheet from the Allegro PCB SI menu.,Constraint Manager – Workbook and Worksheet (cont),,,Spreadsheet selected,Constraint values,,Select Setup Electrical Constraint Spreadsheet from the Allegro PCB SI menu.,Worst case bubbles to the top,,,Extracting a Topology Using Constraint Manager,Check this box to extract routed actuals.,Check this box to extract routed interconnects.,,,,,Electrical Constraint Set,Import Electrical CSet,Create Electrical CSet,A Topology Template can be applied to a net or group of nets by importing an Electrical CSet. An Electrical CSet can be created in the Constraint Manager and referenced to a net or group of nets.,Electrical CSets – All Constraints,In the Constraint Manager, select Electrical Constraint Sets All Constraints Spreadsheet.,Pin pairs for which the constraint values are defined in this template.,,Imported Electrical CSet.,,,Electrical CSets – All Constraints,In the Constraint Manager, select Electrical Constraint Sets All Constraints Spreadsheet.,,,Determines how the template will be mapped to a 。