A 167 μW 915 MHz gain-boosted LC VCO

This paper presents the design and performance of a gain-boosted LC voltage-controlled oscillator (VCO) topology for ultra-low-power applications. The proposed topology utilizes a second active gain stage to reduce startup power while maintaining acceptable phase noise for low-data-rate applications. The VCO consumes 167 μW from a 1.2 V supply when operating at 915 MHz and exhibits phase noise of -97.9 dBc/Hz at 1 MHz offset. It has a 4-bit digital tuning range of about 80 MHz and an analog tuning range of at least 22.5 MHz. The VCO also has a binary frequency-shift keying (BFSK) modulating system with 550 kHz shift. The VCO is realized in a 0.13 μm CMOS process and occupies 0.26 mm² of area.