LDMOS Technology for RF Power Amplifiers

We show the status of laterally diffused metal-oxide-semiconductor (LDMOS) technology, which has been the device of choice for RF power applications for more than one decade. LDMOS fulfills the requirements for a wide range of class AB and pulsed applications, such as base station, broadcast, and microwave. We present state-of-the-art RF performance of the LDMOS transistor measured with a load-pull test setup, achieving class-AB drain efficiencies of 70% at 2 GHz for on-wafer and packaged devices. Furthermore, the results for several class-AB and Doherty amplifier implementations constructed with this technology are shown. As an illustration, a three-way Doherty application is demonstrated, which has a 7.5-dB back-off efficiency of 47% at 1.8 GHz with a peak power of 700 W and linearity numbers better than -65 dBc.