Texas Instruments has introduced an analog-input audio subsystem that integrates TI's field-proven stereo Class-D power amplifier and stereo DirectPathTM headphone amplifier into one compact package. The audio subsystem is highly flexible, enabling customers to choose different input-to-output configurations and program design parameters to optimize audio performance. Integrating all amplifier channels into one integrated circuit reduces bill of materials, lowers cost and enables sleeker end designs in wireless handsets, portable DVD players, portable gaming and portable media players.
The TPA2050D4 audio subsystem includes a stereo Class-D amplifier which provides a 1.4-W per channel output drive capability into 8-Ohm loudspeakers with 90 percent efficiency to extend battery life in portable applications. The subsystem also features a low-noise stereo DirectPath headphone amplifier that eliminates the need for DC-blocking output capacitors to reduce component count.
The audio subsystem has two stereo single-ended inputs that can be configured as one stereo differential input to achieve better common-mode noise rejection. In addition, the user can program different gains and modes via a 1.8-V compatible I2C interface. For instance, each input channel has a 32-step volume control with an additional four-level gain control for the headphone amplifier. This allows the headphone volume to differ from the loudspeaker volume if both are used simultaneously, increasing flexibility for the consumer. The voltage limiter on the headphone amplifier can help to prevent hearing damage at high volumes and enable compliance of maximum volume standards.