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Audio Amplifier

TFA9872: 9.5V Highly Power-Efficient Class-D Audio Amplifier


The TFA9872 is a 9.5 V boosted Class-D audio amplifier featuring Speaker-as-Microphone (SaM) and Receiver-as-Microphone (RaM) modes. It can deliver up to 10.0 W peak output power to an 8 Ω speaker and up to 11.8 W peak output power to a 6 Ω speaker, at a supply voltage of 4.0 V. 


  • High output power: 5.1 W (average) into 8 W at 4.0 V supply voltage (THD = 1%)

  • Supports handset (16 Ω or 32 Ω) and hands-free (4 Ω or 8 Ω) speaker configurations

  • High-efficiency, low-power dissipation, and low-noise speaker driver

  • Adaptive DC-to-DC converter increases the supply voltage smoothly when switching between fixed boost and adaptive boost modes, preventing large battery supply spikes and limiting quiescent power consumption

  • Wide supply voltage range (fully operational from 2.7 V to 5.5 V)

  • Very low noise output<20 uV (with null data input at Fs = 48 kHz)

  • Low battery current consumption<130 mA (Po = 380 mW, average music power)

  • I2C-bus control interface (400 kHz)

  • Speaker current and voltage monitoring (through the I2S-bus) for Acoustic Echo Cancellation (AEC) at the host

  • 16 kHz /44.1 kHz/48 kHz sample frequencies supported

  • Ultrasonic support (limited) through TDM/I2S running at 96 kHz/192 kHz

  • Configurable full-duplex 4-wire TDM/I2S input interface supporting up to 16 slots

  • Low-latency input path supporting side tone mixing through dedicated PDM input interface

  • Speaker-as-Microphone feedback path on dedicated PDM output interface or TDM interface

  • Programmable interrupt control through a dedicated interrupt pin

  • Low RF susceptibility

  • Thermal foldback and overtemperature protection

  • 15 kV system-level ESD protection without external components on amplifier output

System Block Diagram

Application Block Diagram


  • TFA9872 SDS

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