From the microphone Sensitivity of -30dBV and SNR of 74dB, the smallest input level the microphone can record is -104dBV which is equivalent to 6.31μVrms single-ended. A 1KHz tone with 6.31μVrms is applied to the analog differential inputs of the device under test (DUT) with 0dB gain setting and the digital output is captured with Audio Precision APx555. The following are the results taken on these 2 devices.

Figure 3-12 TAA5212 Captured of Minimum Mic Input

Figure 3-13 ADC6120 Captured of Minimum Mic Input With DRE Disable

Figure 3-14 ADC6120 Captured of Minimum Mic Input With DRE Enable

As shown, these devices are capable of capturing the lowest level at -110dBr from this microphone input without any amplification. The DRE result shows an increase in dynamic range at this signal level and is below the DRE threshold setting.