TPA6139A2 - DirectPath™ 25mW Headphone Amplifier

The TPA6139A2 is a 25-mW, pop-free stereo headphone driver designed to reduce component count, board space and cost. It is ideal for single-supply electronics where size and cost are critical design parameters.

The TPA6139A2 device does not require a power supply greater than 3.3 V to generate its 25 mW, nor does it require a split rail power supply.

The TPA6139A2 device was designed using TI’s patented DirectPath™ technology, which integrates a charge pump to generate a negative supply rail that provides a clean, pop-free ground biased output. The TPA6139A2 is capable of driving 25 mW into a 32-Ω load and 2 Vrms into a 600-Ω load. DirectPath also allows the removal of the costly output DC-blocking capacitors.

The device has fixed gain single-ended inputs with a gain select pin. Using a single resistor on this pin, the designer can choose from 13 internal programmable gain settings to match the line driver with the CODEC output level. It also reduces the component count and board space.

Headphone outputs have &plusm;8-kV HBM ESD protection enabling a simple ESD protection circuit. The TPA6139A2 has built-in active mute control with more that 80-dB attenuation for pop-free mute ON and OFF control.

The TPA6139A2 device is available in a 14-pin TSSOP and a 16-pin QFN. For a pin-compatible, 2-Vrms line driver see DRV612.

• DirectPath™
  • Eliminates Pops and Clicks
  • Eliminates Output DC-Blocking Capacitors
  • 3-V to 3.6-V Supply Voltage
• Low Noise and THD
  • SNR > 105 dB at –1x Gain
  • Typical Vn < 15 µVms 20 to 20 kHz at –1x
    Gain
  • THD+N < 0.003% at 10-kΩ Load and –1x Gain
• 25 mW into 32-Ω Load
• 2-Vrms Output Voltage into 600-Ω Load
• Single-Ended Input and Output
• Programmable Gain Select Reduces Component
  Count
  • 13x Gain Values
• Active Mute With More Than 80-dB Attenuation
• Short-Circuit and Thermal Protection
• ±8-kV HBM ESD Protected Outputs