Aspects of the technology described herein relate to an ultrasound device that may has a phase-locked loop (PLL) that includes a digitally-controlled oscillator (DCO). The DCO includes a plurality of current source unit cells with respective drain switches a plurality of current source unit cells with respective source switches. The plurality of current source unit cells with respective drain switches and the plurality of current source unit cells may have different circuit topologies. Switching on one of the plurality of current source unit cells with respective drain switches may cause a voltage transition at an internal node proceeding in one voltage direction and switching on one of the plurality of current source unit cells with respective source switches may cause a voltage transition at an internal node proceeding in the opposite voltage direction.
