Hi,
We ran into a problem while we were testing TLV320ADC6140 ADC with the ADC6140EVM evaluation board for our new project. Since we would like to reach the best SNR performance without enabling DRE, we used 4 channel summing mode. It worked perfectly at 96kHz sampling rate: measured approximately 6dB better noise floor than in 1 channel mode. However our preferred sampling rate is 192kHz and unfortunately the noise floor at 4 channel mode got a little bit worse compared to 1 channel mode at this sampling rate. We did not enable DRE nor AGC and used Linear phase decimation filter as suggested in Application report SBAA381. We used differential mode on all channels and 2.5k input impedance. On the Audio Serial Bus we used I2S protocol, 32bit word length. Did we miss something on setting 4 channel summing mode at 192kHz sampling rate? Does 4 channel summing really supported at 192kHz sampling rate?
Thank you for your answer!
Best regards,
Akos