Characterization and thermal analysis of a 48 V GaN HFET device technology for wireless infrastructure applications

This report presents the DC, pulsed I–V, small signal, and large signal characteristics of Freescale’s 48 V GaN HFET technology. Characterization of large signal performance for a 12.6 mm at 48V drain bias shows 89 W output power with an associated power density of 7.1 W/mm, linear gain of 17.5 dB, and a power-added efficiency (PAE) of 62%. Analysis of channel temperature over drain bias shows that the maximum channel temperatures at 28 V and 48 V are 107 °C and 245 °C, respectively during saturated RF operation. Data for RF drift over time on a 16.2 mm device show less than 0.2 dB of RF drift for ≫1000 hrs. of testing. This level of RF performance represents a significant ≫4 dB gain and ≫2 W/mm power density improvement over Freescale’s previously reported GaN HFET technology.