The Analog Audio Amplifier Front-end Reference Design demonstrates how to build an audio front end for the TPA32xx class-D amplifier. The AUDIO-OPA1632EVM is the board that was designed to test the results of this design. Design files for the board are available in the reference design product folder. This design utilizes a standard Audio Interface Board (AIB) connector to drive two differential audio inputs of a TPA32xx EVM. The audio front end has selectable gains of 0, 6, and 12 dB and converts two single-ended audio signals into two fully differential signals driving the inputs of the TPA32xx. The distortion and noise performance (THD+N ratio) of the audio front end is significantly better than the THD+N ratio of the TPA32xx, which ensures that the audio front end does not degrade the performance of the overall system.
- Single-ended-to-differential conversion with single fully-differential amplifier optimizes THD+N ratio
- Four parallel connectors for analog inputs: XLR, ¼”-stereo phone, RCA, and SMA jacks
- Gain is adjustable to 0 dB, 6 dB, and 12 dB
- The front end accepts differential inputs in addition to single-ended inputs
- 100-kHz bandwidth matching bandwidth of TPA32xx