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Junichi KODATE Mamoru UGAJIN Tsuneo TSUKAHARA Takakuni DOUSEKI Nobuhiko SATO Takehito OKABE Kazuaki OHMI Takao YONEHARA
The performance of radio frequency integrated circuits (RFICs) in silicon-on-insulator (SOI) technology can be improved by using a high-resistivity SOI substrate. We investigated the correlation between substrate resistivity and the performance of a low noise amplifier (LNA) on ELTRAN(R) SOI-Epi wafersTM, whose resistivity can be controlled precisely. The use of high-resistivity ELTRAN wafers improves the Q-factor of spiral inductors, and thereby increases the gain and narrows the bandwidth of the LNA. Using the high-resistivity ELTRAN wafers, we have successfully fabricated a 2.4-GHz and 5-GHz CMOS LNA in 0.35-µm SOI CMOS technology, whose process cost is lower than the latest CMOS technologies.
Mamoru UGAJIN Junichi KODATE Tsuneo TSUKAHARA
A 1-V 2-GHz receiver that exhibits an image rejection of 49 dB is described. It consists of a low-noise amplifier, a quadrature mixer and on-chip polyphase filters, and was fabricated by 0.2-µm fully depleted CMOS/SIMOX technology. The quadrature mixer employs an LC-tuned folded structure with a common RF input for I and Q channels. This enables 1-V operation, suppresses phase errors in LO signals, and improves the image-rejection performance by about 15-dB compared to a conventional quadrature architecture. The current source of the single-to-balance converter at the mixer input consists of a transistor and an LC tank in a cascode configuration. This enhances its output impedance and improves its common-mode-rejection ratio (CMRR) and the IIP2 characteristics of the receiver. The chip consumes 12 mW with 1-V power supply. The receiver provides an NF of 10 dB with an IIP3 of -15.8 dBm and IIP2 of 12.3 dBm.
Mamoru UGAJIN Junichi KODATE Tsuneo TSUKAHARA
This paper describes a 2.4-GHz downconverter that runs on a 1-V supply. The downconverter integrates an LNA, a quadrature mixer, a complex channel-select band-pass filter (BPF), a limiting amplifier, and a frequency doubler using 0.2-µm CMOS/SOI technology. The frequency doubler doubles the frequency deviation of FM signals as well as the frequency itself, which in turn doubles the modulation index. This improves the sensitivity of FM demodulation. The power consumption of the downconverter is 23 mW with a 1-V power supply. A bit-error-rate (BER) measurement using the downconverter and a demodulation IC shows -76.5-dBm sensitivity at a 0.1% BER.
Akihiro YAMAGISHI Tsuneo TSUKAHARA Mitsuru HARADA Junichi KODATE
A low-voltage 6-GHz-band monolithic LC-tank VCO has been fabricated using 0.2-µm CMOS/SIMOX process technology. The VCO features a tuning-range switching technique to achieve a wide tuning range. The output frequency range is between 5.71 and 6.21 GHz owing to the tuning-range switch. With the tuning-range switch on or off, the phase noise is about -100 dBc/Hz at 1-MHz offset and about -120 dBc/Hz at 10-MHz offset frequency at the supply voltage of 2 V.