EVALUATION KIT AVAILABLE
Digital Input Class D Speaker Amplifier
with Dynamic Headroom Tracking
The 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 var-
ies, due to sudden transients and declining battery life to
maintain a consistent listening experience. A wide 5.5V
to 18V supply range allows the device to reach 19W into
an 8Ω load.
The MAX98371’s flexible digital audio interface (DAI)
supports I2S, left-justified, and TDM formats. The digital
audio interface accepts 32kHz, 44.1kHz, 48kHz, 88.2kHz,
and 96kHz sample rates with 16-/24-/32-bit data sup-
ported for all data formats. In TDM mode, the device can
support up to 16 channels of audio data. A unique clock-
ing 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 tem-
peratures. 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, four-level address pins. The IC
is available in a 0.4mm pitch, 30-bump WLP package. It is
specified over the extended, -40°C to +85°C temperature
●● Notebook Computers
Benefits and Features
●● Wide Supply Range (5.5V to 18V)
●● Dynamic Headroom Tracking Maintains a Consistent
●● Integrated Thermal Foldback Allows Robust
Operation in a WLP Package
●● Remote Output Sensing Allows Up to 20dB THD+N
Improvement When Ferrites Are Used
●● Class D Edge Rate Control Enables Filterless
●● 110dB A-Weighted Dynamic Range
●● Output Power at 1% THD+N:
• 15.7W into 8Ω, VPVDD = 17V
• 13.2W into 4Ω, VPVDD = 12V
●● Output Power at 10% THD+N
• 19W into 8Ω, VPVDD = 17V
• 15.8W into 4Ω, VPVDD = 12V
●● Speaker Amplifier Efficiency
• 91% at 10W into 8Ω, VPVDD = 12V
• 81% at 15W into 4Ω, VPVDD = 12V
●● Extensive Click-and-Pop Suppression
●● Space Saving, 30-Bump WLP Package (2.1mm x
2.6mm x 0.6mm, 0.4mm Pitch)
Simplified Block Diagram
G CLASS D
Ordering Information appears at end of data sheet.
19-7537; Rev 0; 3/15