AKM Semiconductor's ADCs have broadband microphones that enable ultrasonic band recording for multi-microphone recording

     AKM Semiconductor's AK5704 is a low-power 4-channel 32-bit a /D converter (ADC) that integrates a low-noise microphone amplifier. It includes digital signal processing modules, such as filtering and level control, required for digital microphone input. The 32-bit AK5704 achieves a dynamic range of 105 dB and -90 dB THD+N, enabling the product to take full advantage of the performance of high signal-to-noise ratio microphones.

     Multiple AK5704s can be connected in parallel to create a system that supports up to 16 microphones. AK5704 supports sampling frequencies up to 192 kHz and can be combined with a broadband microphone for ultrasonic band recording. It is ideal for high-resolution recording, as well as applications requiring superior far-field response in excess of 5 m.

     The AK5704 is also very energy efficient, consuming only 17mw in active mode. AK5704 integrates a speech activity detector (VAD). Using a VAD as a start trigger can significantly reduce system power consumption, as the rest of the device may be turned off and the VAD consumes only 2.7mW while waiting for the wake word.