A Quadrature Switched Capacitor Power Amplifier

作者：Yuan Wen; Aparin Vladimir; Dunworth Jeremy; Seward Lee; Walling Jeffrey S^*

来源：IEEE Journal of Solid-State Circuits, 2016, 51(5): 1200-1209.

DOI：10.1109/JSSC.2015.2496956

• Class-D power amplifier (PA)
• class-G RF-DAC
• digital PA
• quadrature transmitter
• switched-capacitor power amplifier (SCPA)

This paper presents an all-digital class-G quadrature switched-capacitor power amplifier (Q-SCPA) implemented in 65 nm CMOS. It combines in-phase (I) and quadrature (Q) signals on a shared capacitor array. The I/Q signals are digitally weighted and combined in the charge domain. Quadrature summation results in a 3 dB signal loss; Hence the Q-SCPA utilizes a class-G dual-supply architecture to improve efficiency at backoff. Unlike polar/EER counterparts, the Q-SCPA requires no wideband phase modulator or delay matching circuitry. The Q-SCPA delivers a peak output power of 20.5 dBm with a peak PAE of 20%. It is measured with a 10 MHz, 64 QAM LTE signal, and achieves an ACLR of <-30 dBc, with an EVM <4%-rms.

• 出版日期2016-5