A 30-dBm Class-D Power Amplifier with On/Off Logic for an Integrated Tri-Phasing Transmitter in 28-nm CMOS

This paper presents an eight-unit class-D power amplifier (PA), implemented in 28-nm CMOS. The PA is designed to utilize tri-phasing modulation, which combines coarse-amplitude polar modulation with fine-resolution outphasing components. This new technique enables achieving the back-off efficiency of multilevel outphasing without linearity-degrading discontinuities in the output waveform. Each PA unit contains a cascoded output stage with a 3.6-V supply voltage, and on/off logic enabling multilevel operation controlled by low-voltage signals. The PA achieves a peak output power of 29.7 dBm with a 34.7% efficiency, and is verified to operate with aggregated LTE signals at bandwidths up to 60 MHz at 1.7-GHz carrier frequency.

[1]  Aritra Banerjee,et al.  High efficiency multi-mode outphasing RF power amplifier in 45nm CMOS , 2015, ESSCIRC Conference 2015 - 41st European Solid-State Circuits Conference (ESSCIRC).

[2]  Mikko Valkama,et al.  13.5 A 0.35-to-2.6GHz multilevel outphasing transmitter with a digital interpolating phase modulator enabling up to 400MHz instantaneous bandwidth , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[3]  Yorgos Palaskas,et al.  A Flip-Chip-Packaged 25.3 dBm Class-D Outphasing Power Amplifier in 32 nm CMOS for WLAN Application , 2011, IEEE Journal of Solid-State Circuits.

[4]  Mikko Valkama,et al.  Spectral Effects of Discrete-Time Amplitude Levels in Digital-Intensive Wideband Radio Transmitters , 2018, 2018 IEEE International Symposium on Circuits and Systems (ISCAS).

[5]  An-Yeu Wu,et al.  Multilevel LINC System Designs for Power Efficiency Enhancement of Transmitters , 2009, IEEE Journal of Selected Topics in Signal Processing.

[6]  Yorgos Palaskas,et al.  A Transformer-Combined 31.5 dBm Outphasing Power Amplifier in 45 nm LP CMOS With Dynamic Power Control for Back-Off Power Efficiency Enhancement , 2012, IEEE Journal of Solid-State Circuits.

[7]  Mikko Valkama,et al.  Class D CMOS power amplifier with on/off logic for a multilevel outphasing transmitter , 2016, 2016 IEEE International Symposium on Circuits and Systems (ISCAS).