Audio codec brings digital microphone support and noise cancellation to compact electronics

The MAX9867 offers a complete voice record path with stereo differential microphone inputs and stereo single-ended line inputs. Integrated support for traditional analog microphones as well as digital microphones allows engineers to future-proof their designs.

For enhanced audio performance, the device includes a set of programmable digital filters that can be utilized during audio recording or playback. The filters provide the product designer with a simple method to eliminate system noise, such as the GSM packet frequency (217Hz), from the audio path. They also allow custom noise-cancellation schemes for improved isolation of vocal frequencies. Additionally, the headphone amplifier incorporates comprehensive click-and-pop circuitry that suppresses audible noise during volume changes, power on, and power off. This circuitry eliminates the large, costly capacitors required by conventional designs.

A low-power audio codec, the MAX9867 consumes a mere 6.7mW during stereo audio playback due to the combination of 1.8V single-supply operation with a highly efficient stereo headphone amplifier. This very low power consumption conserves battery life while ensuring high-quality audio playback in portable devices.