1 Features
1• Ultra Low-Power, High-Performance DirectPath™
Class-G Headphone Amplifier
– Ground-Centered Output Eliminates DC-
Blocking Capacitors
– 30 mW/Ch into 32 Ω / Ch at 1% THD+N variable–
–42 dB to +6 dB Volume Control
– 2.0 μV Output Noise at –42 dB Gain
– 91-dB PSRR
– Ground Loop Rejection for Reducing Crosstalk
• Fully Differential Mic Preamplifier With Variable
Gain and 3.4-μV Low Noise
– Integrated AC-Coupling Capacitor
– Ground Loop Rejection for Reducing
Headphone to Mic Crosstalk DC•
Choice of Two Mic Bias Voltages: 2.0 V and 2.6 V
– 92-dB PSRR
– Integrated Programmable Mic Bias Resistor
• Advanced Accessory Insertion, Removal, and
Type Detection
• Passive Multi-button Support Using 10-Bit SAR
ADC
– Implements Proprietary Scheme to Reduce
Error Caused by Audio Playback Signal in
Presence of Finite Resistance on Headset
Ground Return Path
• Integrated Level-4 IEC ESD Protection on Jack
Connected Pins (on EVM)
• Ultra Low-Power Chip Shutdown Mode
• I2C Interface
• Short-Circuit Protection
• 0.4-mm Pitch 25-Ball WCSP

2 Applications
• Smart Phones and Wireless Handsets
• Portable Tablets
• Notebook PCs and Docking Stations

3 Description
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.