A biopsy device may include a needle, a cutter, and a handpiece. A vacuum pump in the handpiece may provide a vacuum to the needle and/or to the cutter. A pressure pump in the handpiece may also provide pressurized air to the needle and/or to the cutter. A motor in the handpiece may drive the vacuum pump, the pressure pump, and/or the cutter. A vacuum sensor may sense a vacuum level within the biopsy device, and cause initiation of operational cycles in response to sensed vacuum levels. Portions of a valving mechanism and a clutching mechanism may be integrally formed. A clutching and valving mechanism may be driven by a first battery-powered motor; and a cutter, pressure pump, and vacuum pump by a second battery-powered motor. A biopsy device may thus provide vacuum, pressurized air, and power from within a handpiece, such that the biopsy device is tetherless.