An energy-efficient self-charged crystal oscillator with a quadrature-phase shifter technique

An energy-efficient self-charged crystal oscillator (SCXO) employing a quadrature-phase shifter is proposed to provide wide-range pulse injection timing for power consumption reduction. The passive resistors of quadrature-phase shifter can be shared by the startup circuit to save area consumption. The double-edge extractor and the low-power comparator are added to reduce the power consumption. The proposed 32.768-kHz energy-efficient SCXO, fabricated in a 40-nm CMOS technology, consumes 34.3 nW under a 1 V supply.