An innovative MEMs peizo speaker

MEMs micro-speaker development has trailed behind MEMs microphone development by over two decades due to fabrication and acoustical challenges. While MEMs microphones only need to respond to minuscule displacement, generating sound energy requires both motor force and far higher volume velocity of the transducer mechanism. Recent development of a full bandwidth piezo-MEMs micro-speaker with a silicon diaphragm creates a rigid, light, fast responding transducer with high resistance to humidity and low thermal expansion. Fabricated using a monolithic MEMS semiconductor process eliminates calibration and driver matching. 20 Hz to 20kHz frequency response is delivered in occluded earbud, IEM, and hearing aid applications. The 20 kHz resonance peak provides a smoothly increasing response in the upper octaves. This extra amplitude allows for a significant increase in hearing aid gain and bandwidth over balanced armature transducers. The device is packaged in both top- and side-fire port configurations with earbud EVKs currently shipping. Integration of the amp, on the package substrate or SiP module, opens possibilities for more compact devices, longer battery life, lower cost, and more robust construction. The combination of audio fidelity, size, and speaker to speaker uniformity is not possible with traditional voice coil or hybrid MEMS approaches.