A SiGe bipolar-MOSFET cascode power amplifier with improved linearity for low-power broadband wireless applications

• Published in: 2013 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications pp. 22 - 24
• Main Authors: Ruili Wu, Lopez, J., Yan Li, Lie, D. Y. C.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.01.2013
• Subjects: Bandwidth; BiCMOS integrated circuits; Bipolar-MOSFET (BiFET); cascode power amplifier (PA); Gain; Linearity; LTE; Power amplifiers; Radio frequency; SiGe BiCMOS PA; Silicon germanium
• ISBN: 9781467329156; 1467329150
• DOI: 10.1109/PAWR.2013.6490176

In this paper, a novel bipolar-MOSFET (BiFET) cascode differential power amplifier (PA) is proposed and fabricated, showing strong improvement on the linearity performances over those of the conventional bipolar-bipolar cascode PA. The two-stage differential BiFET cascode PA achieves P out of 25.7 dBm with 52.1 % power-added-efficiency (PAE) in the continuous wave (CW) measurement at 900 MHz. A conventional bipolar-bipolar cascode PA is designed in a similar configuration to compare with the BiFET cascode PA performances, using the LTE 16QAM 5/20 MHz signals as inputs. The measurement results show that the BiFET cascode PA significantly improves the linearity performances over those of the conventional bipolar-bipolar cascode PA in terms of error vector magnitude (EVM), adjacent channel leakage ratio (ACLR) and the transmission output spectra. These linearity improvements are more visible at lower P out levels, and become particularly striking as the signal bandwidth increases to 20 MHz. The SiGe PAs are designed and fabricated in a 0.35-μm SiGe BiCMOS technology with through-wafer-vias (TWVs) for low-power broadband wireless applications.