Home // International Journal On Advances in Telecommunications, volume 8, numbers 1 and 2, 2015 // View article
Authors:
Yan Li
Jerry Lopez
Donald Lie
Keywords: Broadband; envelope-tracking (ET); hybrid switching supply modulator (SM); long-term evolution (LTE); SiGe; power amplifier (PA); WiMAX
Abstract:
This paper presents an overall design path towards our fully monolithic envelope-tracking (ET) power amplifier (PA) in a 0.35 µm SiGe BiCMOS technology. First, a discrete hybrid switching supply modulator (SM) is designed to study the effects of its switching frequency and bandwidth limitation to the linearity and efficiency of an overall ET-PA. Next, the same circuit configuration is used for our CMOS SM which modulates our self-biased cascode SiGe PA with the proposed envelope shaping function. By analyzing the power losses of the CMSO SM under our special ET operation, we show the SM can still achieve high efficiency with a relatively low switching frequency, which helps to improve the system linearity. At 1.9 GHz, our BiCMOS cascode ET-PA delivers the maximum linear output power (Pout) of 24/23.4 dBm with the overall power-added-efficiency (PAE) of 41%/38% for the long-term evolution (LTE) 16QAM 5/10 MHz signals, respectively. Meanwhile, good linearity and low spurious emission are achieved without the need of digital predistortion (DPD).
Pages: 35 to 47
Copyright: Copyright (c) to authors, 2015. Used with permission.
Publication date: June 30, 2015
Published in: journal
ISSN: 1942-2601