A Wide Band VCO with Automatic Frequency, Gain, and Two-Step Amplitude Calibration Loop for DTV Tuner Application

YoungGun PU  Kang-Yoon LEE  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.12   pp.1496-1503
Publication Date: 2009/12/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.1496
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
wide tuning range,  frequency,  amplitude,  gain,  calibration,  voltage controlled oscillator (VCO),  

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This paper presents a wide tuning range VCO with an automatic frequency, gain, and two-step amplitude calibration loop for Digital TV (DTV) tuner applications. To cover the wide tuning range, the fully digital automatic frequency calibration (AFC) loop is used. In addition to the AFC loop, a two-step negative-Gm tuning loop is proposed to provide the optimum negative-Gm to the LC tank in a wide frequency range with a fine resolution. In the coarse negative-Gm tuning loop, the number of active negative-Gm cells is selected digitally based on the target frequency. In the fine negative-Gm tuning loop, the negative-Gm is tuned finely with the bias voltage of the VCO. Also, the digital VCO gain calibration scheme is proposed to compensate for the gain variation in a wide tuning range. The VCO tuning range is 2.6 GHz, from 1.7 GHz to 4.3 GHz, and the power consumption is 2 mA to 4 mA from a 1.8 V supply. The measured VCO phase noise is -120 dBc/Hz at 1 MHz offset.