A wide-band high-efficiency envelope tracking supply modulator for cellular front-end module

An Envelope Tracking (ET) supply modulator used for battery supplied Front-End Module(FEM) is fabricated with Global Foundries 0.18μm silicon-on-insulator (SOI) CMOS process. The hybrid topology supply modulator employs ground-boosting technique to improve efficiency. A novel compensation topology along with a novel OTA are used for improved GBW and stability with a limited quiescent current. In measurement, for 6MHz CW signal and 7.3Ω//220pF load, the supply modulator achieves an efficiency of 85% with a SFDR of 57dBc and an efficiency of 80% with a SFDR of 38dBc.