A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters
| Autor: | Christopher M. Thomas, Young-Sub Yuk, Gyu-Hyeong Cho, Chang-Seok Chae, Yi-Gyeong Kim, Gert Cauwenberghs, Jong-Kee Kwon, Chul Kim, Sohmyung Ha |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Total harmonic distortion business.industry Amplifier 020208 electrical & electronic engineering RF power amplifier Ripple Electrical engineering 020206 networking & telecommunications 02 engineering and technology CMOS Modulation 0202 electrical engineering electronic engineering information engineering Linear amplifier Electrical and Electronic Engineering business Voltage |
| Zdroj: | IEEE Journal of Solid-State Circuits. 53:1653-1665 |
| ISSN: | 1558-173X 0018-9200 |
| Popis: | The parallel combination of a switching and a linear amplifier in the supply modulator for RF power amplifiers (PAs) has the potential to enhance energy efficiency while achieving wider bandwidth and lower ripple output voltage. In this paper, a linear amplifier that features a buffered-switching Class-AB bias scheme is presented for the supply modulator in polar-transmitter structures achieving 500 MHz of small-signal 3-dB bandwidth at a 1.2-V supply. The linear amplifier absorbs and cancels up to 60 mA of ripple current from the switching amplifier. As such, the ripple in the output voltage of the hybrid linear-switching supply modulator is less than 7.5 mVpp. The switching amplifier provides most of the signal current for greatest efficiency owing to a proposed rail-to-rail current-sensing circuit. Current feedback in the switching amplifier achieves 1.68-MHz unity-gain bandwidth at 6-MHz switching frequency. Harmonic distortion in the output voltage of the supply modulator is below 40 dBc at 0.8 Vpp sinusoidal input up to 9 MHz. The peak efficiency is 87.7% for a 8.25- $\Omega $ load, while the maximum output power is 23.6 dBm for a 4.99- $\Omega $ load. The chip measures 1.35 mm2 in a 65-nm standard bulk CMOS process. |
| Databáze: | OpenAIRE |
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