1-2hit |
Naoya AZUMA Shunsuke SHIMAZAKI Noriyuki MIURA Makoto NAGATA Tomomitsu KITAMURA Satoru TAKAHASHI Motoki MURAKAMI Kazuaki HORI Atsushi NAKAMURA Kenta TSUKAMOTO Mizuki IWANAMI Eiji HANKUI Sho MUROGA Yasushi ENDO Satoshi TANAKA Masahiro YAMAGUCHI
Substrate noise coupling in RF receiver front-end circuitry for LTE wireless communication was examined by full-chip level simulation and on-chip measurements, with a demonstrator built in a 65nm CMOS technology. A CMOS digital noise emulator injects high-order harmonic noises in a silicon substrate and induces in-band spurious tones in an RF receiver on the same chip through substrate noise interference. A complete simulation flow of full-chip level substrate noise coupling uses a decoupled modeling approach, where substrate noise waveforms drawn with a unified package-chip model of noise source circuits are given to mixed-level simulation of RF chains as noise sensitive circuits. The distribution of substrate noise in a chip and the attenuation with distance are simulated and compared with the measurements. The interference of substrate noise at the 17th harmonics of 124.8MHz — the operating frequency of the CMOS noise emulator creates spurious tones in the communication bandwidth at 2.1GHz.
Takahiro NAKAMURA Tomomitsu KITAMURA Nobuhiro SHIRAMIZU Toru MASUDA
A wide-tuning-range LC-tuned voltage-controlled oscillator (LC-VCO) – featuring small VCO-gain (KVCO) variation – has been developed. For small KVCO variation, a serial LC-resonator that consists of an inductor, a fine-tuning varactor, and a capacitor bank was added to a conventional parallel LC-resonator that uses a capacitor bank scheme. The resonator was applied to a 3.9-GHz VCO for multi-band W-CDMA RFIC fabricated using 0.25-µm Si-BiCMOS technology. The VCO exhibited KVCO variation of only 21%, which is one third that of a conventional VCO, with a 34% tuning range. The VCO also exhibited a low phase noise of -121 dBc/Hz at 1-MHz offset frequency and a low current consumption of 6.0 mA.