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28 The PCB Design Magazine • March 2016 and ground planes. This in turn, degrades the performance and reliability of the product. There is also a high risk of thermal failure in adverse operating environments. Independently from power integrity analysis, thermal analysis can de- tect hotspots, overheated components and other thermal issues that may degrade the product. Thermal simulation can be run by itself or co- simulated with DC voltage drop. Thermal-only simulation takes into account the heat dissipated from ICs and other components, the environ- mental air flow and ambient temperature. Ther- mal/DC drop co-simulation additionally includes the heat produced by current flowing through copper connecting the voltage regulator module (VRM) and DC sink component pin models. Of course, the use of today's advanced rout- ing technology can provide stunning produc- tivity gains, particularly with the latest high- speed DDR4 memory interfaces requiring your undivided attention to detail. Once set up with constraints defined for all critical signals, rout- ing can be completed and verified in a fraction of the time required using manual techniques. In conclusion, the use of virtual prototyping including signal and power integrity, thermal analysis, DFM and 3D validation, is now becom- ing imperative in order to reduce design itera- tions, meet aggressive schedules and stay ahead of the competition, But, what about the cost? One could choose an enterprise solution that would undoubtedly do the job, or you could consider an affordable bundle of tools that are comparatively priced to desktop solutions, yet provide all the necessary tools required for the most demanding design. Is it time to look at more efficient alternatives? Points to Remember: • The choice of PCB design tools, until now, has been limited to high-end, enterprise-level solutions or entry-level desktop solutions. • A typical a high-speed computer based de- sign takes two or three iterations to develop a working product, costing engineering time and delaying time-to-market. • The design changes that occur early in the design process are less expensive when com- pared to those that take place after it is intro- duced into full scale production. • Development teams are finding that they need to employ analysis tools to verify their de- sign before release. • Virtual prototyping, including signal and power integrity, thermal analysis, DFM and 3D interference validation, impart fewer design spins and are essential for design efficiency. • Entry-level tools tend to rely on the skills of the engineer and PCB designer to detect pos- sible issues during the design process. A more constraint-driven, correct by construction ap- proach is required for complex designs. • The reuse of constraints, from a previous proven design, not only ensures consistent rules but also minimizes the possibility of errors. • Net classes are used to organize and speed- up the definition of routing constraints for nets with similar properties. • Designers still rely on eye-balling to pick up many inconsistencies in the layout. How- ever, DRC tools can verify complex design rules that are not easily simulated, such as EMC con- straints. • Independently from power integrity anal- ysis, thermal analysis can detect hotspots, over- heated components and other thermal issues that may degrade the product. • Today's advanced routing technology can provide stunning productivity gains. PCBDESIGN References 1. Barry Olney Beyond Design columns: Introduction to Board Level Simulation and the PCB Design Process, Design for Profit. 2. Steve Hughes, Mentor Graphics PADS Pro- fessional documentation, Why Impose Design Constraints? 3. For information about PADS Professional, click here. Barry Olney is managing director of In-Circuit Design Pty Ltd (ICD), Australia. This PCB design service bureau specializes in board-level simulation, and has developed the ICD Stackup Planner and ICD PDN Planner software. To read past columns, or to contact Olney, click here. the need for speed: strategies for design efficiency