A multimode CMOS PA with a single propagation path

• Published in: Analog integrated circuits and signal processing 2021-08, Vol.108 (2), p.421-435
• Main Authors: Santos, Fávero G., Leite, Bernardo R. B. de A., Mariano, André A.
• Format: Article
• Language: English
• Subjects: Circuits and Systems; CMOS; Electric potential; Electrical Engineering; Engineering; Power amplifiers; Propagation; Signal,Image and Speech Processing; Temperature analysis; Topology; Transistors; Voltage
• ISSN: 0925-1030; 1573-1979
• DOI: 10.1007/s10470-021-01886-z

In this paper a four mode 130 nm RF CMOS power amplifier (PA) in a single propagation path topology is presented and evaluated with IEEE 802.11ax signals. Specifically, this configuration is supported by three main concepts: scaling of the supply voltage, consecutive voltage amplifications and selection of the operation modes of transistors (saturation or triode). The concept is tested at 2.4 GHz and the obtained post-layout simulation results are reported. The four efficiency profiles of the proof-of-concept are: N4S3A1 (common-source), low-power (N4S2A2), medium-power (N4S1A3), and high-power (N4S0A4). For each of those modes the 1 dB output compression point (OCP 1dB ) and the power added efficiency (PAE) at OCP 1dB are evaluated with the following results, respectively: 17.5 dBm and 23 % (N4S3A1); 16.8 dBm and 28.1 % (N4S2A2), 18.1 dBm and 28.9 % (N4S1A3), and 19.9 dBm and 25.7 % (N4S0A4). In terms of process–voltage–temperature analysis, the worst and best performances obtained for OCP 1dB and PAE at OCP 1dB are: 13.9 dBm and 16.8 dBm, 13.6 % and 29.3 % (N4S3A1); 15.4 dBm and 19.3 dBm, 20.3 dBm and 40.7 % (N4S2A2); 16.7 dBm and 19.3 dBm, 21.7 % and 36.6 % (N4S1A3); 19.2 and 21.2, 18.9 % and 36 % (N4S0A4). As for IEEE 802.11ax signals under 16 QAM operation (MCS4), the PA performs an output power at limit EVM (-19 dB) for modes N4S3A1, N4S2A2, N4S1A3, and N4S0A4 of: 14.7 dBm, 15.3 dBm, 16.7 dBm, and 17.8 dBm.