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Module designs, and specifically handset power amplifier (PA) and front-end module (FEM) designs, are at a crossroads. Traditionally, the module has been an integration platform for discrete functional blocks enabled by considerable design margin, reasonable size and power constraints, and the luxury of predicted performance from cascaded analysis.

Although these issues may not be of concern in many current module designs, they soon will be, because increasing cost, complexity, integration and functionality will drive modules into realms of new design concerns. For years, going back to the Radiation Laboratory days, the majority of the time and effort invested in module design was spent on individual components.

Cascaded analysis by hand and then by spreadsheet, with the associated tradeoff among related blocks, left the majority of the module design task to finding either what combinations of individual block parametrics gave the highest yield, or what the various bonding or surface-mount technology (SMT) passive values were for “tuning in” marginal designs.

Later, with the advent of easy-to-use electromagnetic (EM) solvers or tools, some post-layout consideration was given to “design” of the module but, in reality, this was and continues to be more of a verification step.

With the explosion of the wireless market, all this is changing. Consumers want more features for the same price, vendors need more performance at a lower price and module designers are being pressured to deliver.

With more functionality going into a smaller footprint, the module can no longer be simply an integration platform. As performance requirements become more stringent, there is precious little margin to meet specifications, let alone design so that functional blocks can be merely cascaded; coupling among components must be minimized or even leveraged, if a PA/FEM module is to be successful in the marketplace.

Taking advantage of ever-shrinking market windows means that there may be time for a few design paths, but the days of doing iteratively endless module EM designs, followed by yet another printed circuit board (PCB) manufacturing run, are a thing of history.

In this article, a modern module design approach is explored, with emphasis on efficient design flow and effective methodology. The historical approach is reviewed and compared with a newer approach, looking at breaking down the previous barriers to actually designing modules by focusing on some very fundamental changes in design: multimedia design, co-simulation and early availability of EM. At a very high level, the flow is the same: partition the design, implement the individual functional blocks, integrate on the module and verify. But this is where the similarity ends, and the overall effect of the new design approach is to provide a higher degree of confidence in less design cycle time, ensuring that the module will be manufacturable in volume, cost-effective and will achieve its market window of opportunity.