The NAU8331 is a Class D audio amplifier with integrated highly-efficient and industry leading boost converter, SAR ADC, and a stereo Audio ADC for the small speaker application in mobile phones, tablets, Personal Computers (PCs), and other portable devices, where the loudness and audio quality of speaker is limited by small and thin speaker geometry.

The 24-bit high quality stereo audio ADC can be used to collect real time current and voltage information from the speaker output. This can be sent to an external processor through either I2S or Soundwire for speaker protection. The integrated SAR ADC can also be used to measure the voltage level on the battery supply, and sense the junction temperature and ambient temperature for further device control.

The intelligently adaptive and highly efficient boost converter can boost the supply voltage up to 10.8V while producing only 18 uVRMS ultra-low idle output noise. It can also control the supply rail of Class D amplifier in very fine 0.16V steps based on the input signal level and the battery supply voltage. This can be used to maximize the loudness of small speakers, while providing superior power efficiency at all signal levels.

The NAU8331 supports both I2C/I2S and Soundwire slave interfaces. This simple 2-pin Soundwire interface can be connected to the Soundwire master device in a host to transport both multiple data channel and control information by using time division multiplexing, which allows up to 11 concurrent slave connections into one master.

The NAU8331 operates with analog supply voltages from 1.6V to 1.98V, while the battery supply voltage can operate from 2.9V to 5.5V. The NAU8331 operating temperature range is specified from -40°C to +85°C, and is available in CSP 35 Ball package with a 0.5mm ball pitch.