Design Of High-performance LC Voltage Controlled Oscillator

Based on charted semiconductor 0.35μm RF CMOS process, a LC voltage controlled oscillator in application of PLL Frequency Synthesizer has been designed. First of all, several kinds of basic structure of LC oscillators and their phase noise theories were analyzed in detail, then, a LCVCO is designed using full custom design method and each part of the circuits is analyzed, finally, the test chip is fabricated and a simple testing method has been presented at PCB level.The output tuning range was 1810MHz~1930MHz, and the LCVCO used cross-coupled complementary full differential topology with switching capacitor array to cover frequency band, which could lower the VCO gain in each single band and further lower the whole PLL's phase noise performance.Full custom, from top to bottom design method has been used for this LCVCO. Cadence SpectreRF simulator was used to simulate the design, Virtuo to compose the layout and Mentor Calibre to DRC, LVS and PEX verification, finally, Synoposys Hspice was used to post layout simulate.The result of simulation showed that the tuning range of LCVCO could cover the range of 1810MHz~1930MHz, at ss, tt, ff process corner when temperature varying form -25℃to 80℃, meeting the design requirement and phase noise could be low as -125.5dBc/Hz @900 kHz.