The TPA6166A2 single-chip headset interface IC simplifies the challenges of detecting what kind of device an end user has plugged into the headphone jack while delivering excellent audio quality. The device enables smaller end products by integrating a high-performance, low-power DirectPath variable-attenuation class-G stereo headphone amplifier, variable-gain microphone preamplifier with bias with advanced accessory detection circuitry, all in a tiny 5-mm × 5-mm terminal, 0.4-mm pitch WCSP package. The class-G headphone amplifier maximizes battery life by adjusting the supply voltage of the headphone amplifier based on audio signal level. With 8-µV output noise at 0-dB gain and PSRR of 91 dB, the headphone amplifier provides excellent audio performance. DirectPath eliminates the need for DC-blocking capacitors. The microphone preamplifier has two programmable gains of 12 dB and 24 dB, and 3.4 µV input referred noise. The microphone bias voltage has two programmable settings of 2 V and 2.6 V. The bias output drives up to 1.2 mA of current, has a low output noise of 2 µV, and 92-dB PSRR, providing excellent rejection of power supply noise in wireless handsets. The advanced accessory detection algorithm automatically detects six supported accessories and enables or disables internal components.