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To relax the trade-off relationship between tuning range and phase noise, we have developed a new interpolative ring-VCO having a wide control voltage range over which frequency variation is linear. A wide lock-range, low phase noise PLL incorporating this VCO has been fabricated in a 90 nm CMOS process. It successfully operates at from 3.432 to 4.488 GHz (LF-mode) and from 6.600 to 9.240 GHz (HF-mode), with 528 MHz spacing, while drawing 30 to 37 mA from a 1.5 V supply. Measured integrated phase noise is below a targeted 4 degrees in both modes when the reference frequency is 264 MHz and less than 4 degrees in the LF-mode when it is 66 MHz.