The TPA2050D4 features a stereo Class-D power amplifier along with a stereo DirectPath 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 Ω 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 DC- blocking 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. The DirectPath headphone amplifier gains are 0 dB (default), -6 dB, -12 dB, and -20 dB, selected through the I2C interface. This allows the headphone volume to be different from the loudspeaker volume if both are used simultaneously. The TPA2050D4 has a 2:1 input MUX for audio source selection. The MUX has mode control which directs the input-to-output signal path. Mode and gain controls operate from a 1.8 V compatible I2C interface. The voltage supply range for both the Class-D amplifiers and the headphone charge pump is 2.5 V to 5.5 V. The Class-D amplifiers use a combined 7 mA and the headphone amplifier uses 10 mA of typical quiescent current. Total supply current reduces to less than 2µA. The TPA2050D4YZK is available in a 25-ball 2.61 mm × 2.61 mm WCSP package. The TPA2050D4 features a stereo Class-D power amplifier along with a stereo DirectPath 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 Ω 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 DC- blocking 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. The DirectPath headphone amplifier gains are 0 dB (default), -6 dB, -12 dB, and -20 dB, selected through the I2C interface. This allows the headphone volume to be different from the loudspeaker volume if both are used simultaneously. The TPA2050D4 has a 2:1 input MUX for audio source selection. The MUX has mode control which directs the input-to-output signal path. Mode and gain controls operate from a 1.8 V compatible I2C interface. The voltage supply range for both the Class-D amplifiers and the headphone charge pump is 2.5 V to 5.5 V. The Class-D amplifiers use a combined 7 mA and the headphone amplifier uses 10 mA of typical quiescent current. Total supply current reduces to less than 2µA. The TPA2050D4YZK is available in a 25-ball 2.61 mm × 2.61 mm WCSP package.