Hi,
we are evaluating the TLV320ADC5140 on a custom PCB to sample analog MEMS with 4 channels at FS 192 kHz sampling frequency and bitclock BCLK 24.6 MHz.
The configuration is the base one from the datasheet with auto PLL setting. With a 1 kHz sine test signal the device is showing an impressive SNR performance as shown in the datasheet.
However, a 40 kHz test signal is strongly distorted with a degraded SNR.
The question is: Is the TLV320ADC5140 usable for signals greater than 20 kHz?
We are aware that this device is mainly designed for audio purposes. But with HPF and BIQUAD off, at least in theory the CIC-LP filters should be able to handle this. Also, the internal delta-sigma ADC runs at 6.144 MHz. We have seen SBAA377A and are aware that potential interferers could produce alias. Still, there is no statement that any element of the signal processing chain is blocking a signal greater than 20 kHz.
Could you please advise if the device is usable for signals greater than 20 kHz. If yes, is there any custom configuration to achieve this? Many of the registers are not documented. Therefore, it is impossible for us to find out with the given documentation how to achieve a custom device configuration for the given application.
Thanks
