The Right Audio Codec for Hearables and Wearables

The Right Audio Codec for Hearables and Wearables

Popping in your wireless earbuds, you settle in for a long international flight, catching up on hours of podcasts. You expect to hear every word loudly and clearly despite the din in the aircraft. And you fully assume that you won’t have to charge your device mid-way through your journey.

Great audio quality and long battery life are key expectations for most users of hearables, wearables, and other portable devices. From a design standpoint, however, it’s a tall order to meet, given the tight form factors of these devices. Some products are great at delivering loud sound for noisy environments, but once the user moves to a quiet room, the noise floor becomes audible in the form of a low-level hiss. Other products have great sound quality, but it just doesn’t come through loud enough in a noisy space.

How can you meet user expectations while balancing the tradeoffs? Choose an audio device designed to deliver a high level of audio quality at the lowest possible power.

Users of small, portable electronics like earbuds expect great audio quality along with extended battery life.

To minimize power consumption, some audio devices are designed with power-saving features in their playback path. For example, a headphone amplifier could use a charge pump to dynamically adjust the power supply levels based on the audio signal level. When the audio content is quieter, the reduced supply levels save power and extend battery life. When the audio signal levels increase, the power supply level automatically increases to continue delivering loud and distortion-free audio. Once the audio signal level decreases again, the supply level scales down to save power.

For enhanced audio quality, look for an audio codec with programmable functions designed to deliver the best listening experience:

  • DC blocking filters that remove the offset from the audio signal
  • Low-pass filters that remove high-frequency, inaudible noise and signals
  • Analog gain and digital volume controls, which allow upward and downward adjustment of the audio amplitude
  • Dynamic range controls that smooth out peak audio volume for a consistent listening experience
  • Biquad filters and parametric equalizers that allow you to tune the audio response of your design; for example, in the playback path you could boost the bass, adjust the treble, or compensate for the response of the headphone speaker

High Performance, Low Power, Small Footprint

Maxim has a stereo audio codec that meets the requirements for great audio quality and minimized power consumption, providing the capabilities we’ve just outlined. The MAX98090 is a fully integrated audio codec that delivers high performance with very low power consumption in a small footprint. Its flexible input scheme provides six input pins (WLP) that you can configure as analog or digital microphone inputs, differential or single-ended line inputs, or as full-scale direct differential inputs. You can route analog inputs to the record path ADC or directly to any analog output mixer. The device’s record and playback paths feature programmable FlexSoundRegistered technology hardware DSP. The technology offers low-power, advanced signal processing, including volume control, digital filtering, dynamic range control, biquad filters, and a seven-band equalizer. An integrated stereo Class D speaker amplifier offers efficient amplification and low radiated emissions, while supporting filterless operation. A DirectDriveRegistered stereo Class H headphone amplifier features a ground referenced output that eliminates the need for large DC-blocking capacitors. A differential receiver, or earpiece, amplifier can be reconfigured as a stereo single-ended line output.

Ready to deliver a better audio experience? Learn more about how the MAX98090 can improve audio quality and battery life in your small, battery-powered portable designs by watching this overview video.