Maxim’s MAX98371 is a high-efficiency, mono Class D audio amplifier featuring dynamic headroom tracking (DHT). DHT automatically optimizes the headroom available to the Class D amplifier as the power supply voltage varies, due to sudden transients and declining battery life to maintain a consistent listening experience. A wide 5.5 V to 18 V supply range allows the device to reach 19 W into an 8 Ω load.

Its flexible digital audio interface (DAI) supports I²S, left-justified, and TDM formats. The digital audio interface accepts 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz sample rates with 16-/24-/32-bit data supported for all data formats. In TDM mode, the device can support up to 16 channels of audio data. A unique clocking structure eliminates the need for an external MCLK signal that is typically needed for PCM communication. This reduces pin count and simplifies board layout.

Active emissions limiting with edge rate control minimizes EMI and eliminates the need for output filtering found in traditional Class D devices. 

An 8-bit PVDD supply voltage ADC enables the dynamic headroom tracking circuit. DHT optimizes audio program peak behavior as the supply voltage varies and provides flexible user-defined parameters.

Thermal foldback protection ensures robust behavior when the thermal limits of the device are exercised. The circuit can be enabled to automatically reduce the output power above a user specified temperature. This allows for uninterrupted music playback even at high ambient temperatures. Traditional thermal protection is also available in addition to robust overcurrent protection.

All MAX98371 control is performed using a standard 2-wire, I²C interface. One of sixteen slave addresses can be selected through two 4-level address pins. The IC is available in a 0.4 mm pitch, 30-bump WLP package. It is specified over the extended -40°C to +85°C temperature range.