The TPA2050D4 features a stereo Class-D power amplifier along with a stereo DirectPathTM headphone amplifier. The TPA2050D4 has two stereo single-ended (SE) inputs that can be configured as one stereo differential input. Both input channels have a 32-step volume control and the DirectPath headphone amplifier has a 4-level gain control for coarse volume adjustment. All amplifiers have output short-circuit and thermal- overload protection. The Class-D amplifiers deliver 1.25 W into 8 at 1% THD from a 5.0 V supply, and 700 mW from 3.6 V. The DirectPath headphone amplifier features an output voltage limiter to reduce the maximum output power to one of seven possible limits. The voltage limiter is programmed through the I2C interface. DirectPath eliminates the need for external DCblocking output capacitors to the headphones. The built-in charge pump creates a negative supply voltage for the headphone amplifier, allowing a 0-V DC bias at the output.