SBOSA00B December 2019 – August 2020 OPA1637
PRODUCTION DATA
A common application use case for fully-differential amplifiers is to easily convert a single-ended signal into a differential signal to drive a differential input source, such as an ADC or class-D amplifier. Figure 9-8 shows an example of the OPA1637 used to convert a single-ended, low-voltage signal audio source, such as a small electret microphone, and deliver a low-noise differential signal that is common-mode shifted to the center of the ADC input range. A multiple-feedback (MFB) configuration is used to provide a Butterworth filter response, giving a 40-dB/decade rolloff with a –3-dB frequency of 30 kHz.