Presented herein are implantable medical devices that comprise an implantable portion having a resonant tank circuit that is used to receive signals from one or more external devices. The resonant tank circuit is configured to operate at first and second resonant frequencies, where the first resonant frequency is optimized to exchange data with, and potentially receive operating power from, an external device, while the second resonant frequency is optimized to receive charging power. In certain embodiments, upon initiating operation of the implantable portion with at least one external device, the implantable portion is configured to force tune the resonant tank circuit to the first resonant frequency. That is, when the resonant tank circuit first begins receiving signals from an external device, the signals received at the resonant tank circuit are used to initially tune the resonant tank circuit to the first resonant frequency.
