An 18-mW 1.175-2-GHz Frequency Synthesizer With Constant Bandwidth for DVB-T Tuners

作者：Lu Lei; Chen Jinghong; Yuan Lu; Min Hao; Tang Zhangwen

来源：IEEE Transactions on Microwave Theory and Techniques, 2009, 57(4): 928-937.

DOI：10.1109/TMTT.2009.2014449

• Frequency synthesizer
• loop bandwidth
• loop gain
• phase noise
• voltage-controlled oscillator (VCO) gain
• wideband

A fully integrated 1.175-2-GHz differentially tuned frequency synthesizer aimed for digital video broadcasting-terrestrial tuners is implemented in a 0.18-mu m CMOS process. To maintain phase-noise optimization and loop stability over the entire output frequency range, techniques of constant loop bandwidth are proposed. The voltage-controlled oscillator gain K(VCO) and band step f(res) are both maintained by simultaneously adjusting the sizes of switched capacitors and varactors. Charge pump current I(CP) is programmed to compensate the variation of the division ratio N. The measured results show an in-band phase noise of -97.6 dBc/Hz at a 10-kHz offset and an integrated phase error of 0.63 degrees from 100 Hz to 10 MHz. The measured variations of K(VCO) and f(res) are less than 12.5% and 4.5%, respectively. The variations of the measured phase noise at 10-kHz and 1-MHz frequency offsets are less than 1 dB. The measured 3-dB closed-loop bandwidth is 110 kHz and the variation is less than 9%. The chip draws 10-mA current from a 1.8-V supply while occupying a 2.2-mm(2) die area.

• 出版日期2009-4
• 单位复旦大学