A Push-Pull mm-Wave Power Amplifier with <0.8° AM-PM Distortion in 40nm CMOS

Millimeter-Wave standards like IEEE 802.15.3c and the new 802.11ad have classifications of their PHY to support single-carrier mode and more complex OFDM mode (high-speed interface) with high peak-to-average ratio (PAPR). To improve the efficiency of power amplifiers (PA), the trend is towards Class-AB and Class-B PAs that exhibit better energy efficiency compared to Class-A. However, Class-AB and -B biasing brings along large amplitude-to-phase- modulation (AM-PM) distortion which degrades EVM and ACPR. At the same time, PMOS transistors become attractive in nanometer CMOS as their fMAX exceeds 140GHz. This makes it possible to use both NMOS and PMOS transistors at mm-Wave frequencies. This paper presents a 60GHz complementary Push-Pull PA, using both NMOS and PMOS transistors. An inverter-like architecture which uses both PMOS and NMOS results in the cancellation of AM-PM distortion which is particularly important in high-fidelity amplification of OFDM systems and high-order modulation schemes like 16- and 64-QAM, which are very sensitive to phase distortion. Furthermore, the complementary nature allows deep Class-AB operation, giving a high power efficiency at power back-off comparable to state-of-the-art 60GHz PA structures based on NMOS only. © 2014 IEEE.

ISBN:9781479909186

Publication year:2014

BOF-keylabel:yes

IOF-keylabel:yes

Authors from:Higher Education

Accessibility:Open