A BAW-enabled low-power 5X frequency multiplier

We present a low power Film Bulk Acoustic Wave Resonator (FBAR) enabled multiply-by-5 circuit. We compare its performance to a Q-enhanced LC tank-based multiplier for power, phase noise and carrier-to-spur ratio performance. The FBAR-based frequency multiplier (FM) provides 3 dB and 14.5 dB of phase noise filtering at 1 MHz and 10 MHz offsets, respectively, compared to an LC-based frequency multiplier. Due to its sharp roll-off, it improves spurious suppression by 14.5 dB. We implemented a prototype in 0.13 ¿m RF-CMOS process containing a multiply-by-5 and a differential ring oscillator. Each circuit consumes 700 ¿W while providing a 2 GHz output tone. The FBAR based FM provides a phase noise of -91.5 and -124.5 dBc/Hz at 1 MHz and 10 MHz offsets respectively while the phase noise for the LC tank based FM is -86.5 and -108.5 dBc/Hz.