Modeling Helps Understand ICs

Several reports in the February issue of Microwaves & RF explore various trends in higher integration in monolithic semiconductor circuits, how many different semiconductor processes are being used in the high-frequency industry, often for similar purposes, and the important role of packaging in getting the most from an integrated circuit (IC). A recent reminder from Agilent Technologies concerning a new design kit for its Advanced Design System (ADS) suite of software design tools, focusing on the small-signal processes and products of NXP Semiconductors (the former Philips), also points out the importance of modern computer simulators, such as ADS and Microwave Office from AWR (www.awrcorp.com), in optimizing the performance of semiconductor products.

The NXP small-signal lineup includes diodes, field-effect transistors, and monolithic microwave integrated circuits (MMICs). The design kit includes comprehensive libraries of models stored within the ADS program to help designers essentially try out different circuit strategies in software, rather than going through the time and expense of building different prototype circuits. In the "good old days," it was a matter of working with the S-parameters for a given device and creating input and output (and sometimes between multiple devices) networks in the hopes of achieving the best noise figure, or gain, or output power. With the software, a designer dares to hope of getting the best of all three of those parameters at the same time, and then building the prototype.