11.2.9 Audio Performance

The THS4531 provides excellent audio performance with very low quiescent power. To show performance in the audio band, the device was tested with an audio analyzer. THD+N and FFT tests were run at 1 Vrms output voltage. Performance is the same on both 2.7 V and 5 V supply. Figure 79 is the test circuit used, and Figure 80 and Figure 81 show performance of the analyzer. In the FFT plot the harmonic spurs are at the testing limit of the analyzer, which means the THS4531 is actually much better than can be directly measured. Because the THS4531 distortion performance cannot be directly measured in the audio band it is estimated from measurement in high noise gain configuration correlated with simulation.

Figure 79. THS4531 Audio Analyzer Test Circuit

Figure 80. THD+N on Audio Analyzer, 10 Hz to 24 kHz

Figure 81. 1 kHz FFT Plot on Audio Analyzer