Cree has released an application note describing the accuracy of its large signal models for RF power transistors, which allow RF design engineers to reduce PA design iterations, design time and development costs.
The company’s GaN HEMT devices are growing increasingly popular in applications including: broadband amplifiers, cellular infrastructure, tactical and satellite communications and test instrumentation due to their high efficiency, high gain and relatively simple matching characteristics. However, RF power devices like these are notoriously difficult to predict the large signal performance of due to self-heating and the complex dependence of nonlinearity component parameters on signal level, thermal effects and ambient conditions. Consequently, design engineers must either develop hardware and conduct time-consuming and potentially inaccurate load-pull measurements or rely on the accuracy of large signal models to evaluate such devices in their simulation environments.
To put designers at ease and spare them the time and cost of conducting load-pull measurements, as well as the risk of generating defective data, Cree carefully compared measured and modelled data for its 100W and 200W GaN-on-SiC high electron mobility transistors. Verified using a standard load pull system at optimal impedances over multiple frequencies, the results demonstrate the exceptional accuracy with which the company’s proprietary large signal models represent actual device performance. Further, in addition to providing RF design engineers with valuable assurance and reducing design time and development costs related to load-pull measurements, Cree’s models also allow engineers to conduct in-depth ‘what-if’ analyses that can close layout links and enable faster design cycles and more first-pass design successes.