Simplifying High-Performance Electromyography (EMG) Sensing

Recently, practical applications of high-performance EMG sensing systems have been progressing rapidly. However, their reliance on discrete implementations consisting of multiple ICs and external components created challenges in component selection, analog circuit design, and noise mitigation. In wearable applications, signal acquisition can also become unstable during movement due to Motion Artifacts*.

The AK05611 integrates the AFE functions that are required for both EMG and bioimpedance (BioZ) measurements into a single chip. While simplifying system architecture, it achieves an input-referred noise level of 1.23 μVrms, comparable to that of discrete instrumentation amplifier implementations. This enables detection of subtle muscle movements, including signals generated by small muscles in a little finger. As a result, high-performance EMG sensing that previously required complex discrete architectures can now be achieved with a much simpler design.

In addition, the device incorporates a Motion Artifact Cancellation (MAC) function that utilizes BioZ information to reduce the impact of motion artifacts, enabling stable EMG measurements even during physical activity.

The device supports both I²C and SPI interfaces, allowing flexible channel expansion depending on application requirements. Up to 32 channels can be supported via SPI, making it suitable for multi-point measurement systems.