The TPA6138A2EVM customer evaluation module (EVM) demonstrates the capabilities and operation of the TPA6138A2PW integrated circuit from Texas Instruments. The TPA6138A2PW is a 25mW Pop-Free stereo Head Phone driver designed to replace headphone circuit based on Op amps and passives.
The TPA6138A2 doesn’t require a power supply greater than 3.3V to generate its 25mW output, nor does it require a split rail power supply. 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 TPA6138A2 is capable of driving 25mW into 32ohm. DIRECTPATHTM also allows the removal of the costly output DC-blocking capacitors. The device has adjustble gain, differential inputs with four gain settings controlled by external resistors to match the line driver with the Codec output level. It also reduces the component count and board space compared to Op amps and passives. Headphone outputs have +/-8kV HBM ESD protection enabling a simple ESD protection circuit. The TPA6138A2 has built-in active mute control with more that 80dB attenuation for pop-free mute on/off control.
The TPA6138A2 is available in a 14-pin TSSOP. For a pin compatible 2vrms line driver see DRV632 and the 3Vrms line driver DRV603. This EVM is configured with two RCA phono input connectors for analog input. The output signal is available on a 3.5mm stereo headphone connector. The power supply is connected via a two-pin, 2.54-mm header.
This evaluation board is designed for testing applications such as set-top boxes, LCD/PDP TVs, Blu-ray Disc&trade DVD players, DVD mini-component systems, home theater-in-a-box (HTIB) systems, or soundcards.