Embodiments of the acoustic galvanic isolator comprise a carrier signal source, a modulator connected to receive an information signal and the carrier signal, a demodulator, and an electrically-isolating acoustic coupler connected between the modulator and the demodulator. The acoustic coupler comprises no more than one decoupled stacked bulk acoustic resonator (DSBAR). An electrically-isolating acoustic coupler based on a single DSBAR is physically small and is inexpensive to fabricate yet is capable of passing information signals having data rates in excess of 100 Mbit/s and has a substantial breakdown voltage between its inputs and its outputs.