| Summary: | 博士 === 國立雲林科技大學 === 電子工程系 === 104 === This dissertation presents the analysis techniques and circuit topologies to design and implement the high performance CMOS building blocks for communication systems. All of the proposed high performance CMOS integrated circuits are analyzed, designed, simulated, and measured, which are fabricated in the standard CMOS 0.18μm process. This dissertation is mainly divided into three topics.
The first topic, described in chapter 2, is a variable-gain constant-bandwidth transimpedance amplifier (TIA) for visible light communications. To exploit its distinctive open-loop characteristics, a feedback TIA comprising a feedforward current amplifier (CA-TIA) is investigated. Attributing to the small input impedance with a high-pass response of its feedforward gain element, the stable CA-TIA attains a constant bandwidth of 100MHz as its feedback resistor is varied from 1.5kΩ to 24kΩ. The bandwidth of the CA-TIA is less sensitive to the TIA gain.
The next topic is a variable-gain constant-bandwidth TIA for Gb/s optical wireless communications described in chapter 3. An improved differential common- gate (CG) stage is introduced and employed in the feedforward CA. By exploiting its lower generic input impedance, a variable-gain high-speed CA-TIA with a constant- bandwidth is attained. The CA-TIA with a gain-insensitive bandwidth has been experimentally validated. As the transimpedance gain varies from 55.8dBΩ to 69.3dBΩ, the 3-dB bandwidth of the CA-TIA remains relatively invariable around 1GHz.
The final topic is detailed in chapter 4. A high performance low-cost dual-band CMOS LC voltage-controlled oscillator (VCO) is demonstrated. A fourth-order passive LC resonator configurable by a MOS switch is designed and adopted. The dual-band VCO is capable of operating in 2.53~2.92GHz (low-band) and 4.76~5.33GHz (high-band). The measured output phase noises of the VCO operating at 2.77GHz and 5.01GHz at 1MHz offset are -121.51dBc/Hz and -115.05dBc/Hz, respectively. The VCO dissipates 1.85mW at both the low- and high-band from a supply of 1.2V.
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