Increase in the use of DC-consuming electronic devices and renewable energy sources in daily applications necessitates significant improvements to power conversion and distribution methodologies. DC-DC converters form an integral part of such systems and improvements to overall efficiency, reduction of volume, weight and cost are of utmost interest. Thus, a lot of research efforts are targeted towards identifying each source of loss and attempting to reduce it, thereby improving the associated power electronics. This paper discusses the use of Gallium Nitride (GaN) high electron mobility transistors (HEMT) as switch in a variant of traditional buck-boost topology with integrated magnetics. This combination has several benefits when used together but has not been studied extensively due to the complexity of the associated design and modeling aspects. The modeling of such a converter is described, performance analysis is carried out using MATLAB/Simulink and PLECS, and the comparison with silicon-based converter is presented.