Freescale Semiconductor has launched two LDMOS (laterally diffused metal oxide semiconductor) RF power transistors that allow wireless basestation amplifiers to cover all channels in an allocated frequency band. According to the company, the transistors deliver a good combination of high linearity, high efficiency, and instantaneous bandwidth that extend the signal bandwidth to 160MHz, making them suitable for next-generation amplifier systems. The MRF8P20165WH/S transistor for the 1930 to 1995MHz PCS band and the MRF8P20140WH/S for the 1880 to 2025MHz TD-SCDMA bands F and A supports the wireless spectrum with one amplifier. The amplifiers have dual-path designs, and implement the final stage of a Doherty amplifier with one path as the main amplifier and the other as the peaking amplifier. The MRF8P20165WH/S amplifier has an average power of 37W with an input signal peak-to-average ratio of 9.9dB. It has 47.7% drain efficiency and a power gain of 16.3dB. The MRF8P20140WH/S amplifier has an average power of 24W with an input signal peak to average ratio of 9.9dB. It has a drain efficiency of 43.7% and a power gain of 16dB. The transistors can handle a 10:1 voltage stand waving ratio impedance mismatch while operating at 32V. They have integrated electrostatic discharge protection that makes them resistant to stray voltage.
