Envelope Tracking Systems for RF PA Efficiency Enhancement

Envelope Tracking (ET) has to-date been the most popular technique in wireless handsets for boosting RF power amplifier efficiency at power backoff levels. ET systems have high integration capability within cellular handset devices, and therefore the demand for ET integrated circuits (ICs) to support the smart-phone market continues to rapidly grow as the wireless communication market moves into the fifth-generation (5G) era. The design challenges of envelope tracking systems are discussed in this talk, and an overview of device technologies for supply modulator and ET-PA implementations is given. This talk reviews trends, architectures, and the fundamental operation of the supply modulator, focusing on the performance parameters required to achieve high efficiency, wide signal bandwidth, fast transition time, and low output noise to realize an envelope tracking system, with supply modulator and PA, for LTE/5G and beyond.