PCM1863: THD with 5.5Vpp Input Signal

Hao Wang14

Part Number: PCM1863
Other Parts Discussed in Thread: , OPA1678, TLV320ADC3140, TLV320ADC5140, TLV320ADC6140

Hi Team,

The single-ended full-scale (FS) input of PCM1863 is 2.1Vrms, now the maximum input of our application is 5.5Vpp which is equal to 1.94Vrms. So the input level is -0.67dBFS, but the figure 6 in the datasheet doesn't show the specific turning point where the THD+N is getting worse.

Unfortunately, I don't have a PCM1863EVM at hand, could you please help confirm the THD+N for -0/67dBFS? Thanks!

Best Regards!

Hao

over 5 years ago

0 Collin Wells over 5 years ago

TI__Guru 62895 points

Hello Hao,

The largest signal level with performance specifications in the datasheet is -1dBFS which likely provides some slight margin away from the region where the THD+N begins to increase rapidly. We don't recommend relying on a system requirement for the performance in signal ranges from -1dBFS to 0dBFS to reliably maintain at good performance across operating conditions and device lifetime/aging.

0 Hao Wang14 over 5 years ago in reply to Collin Wells

TI__Expert 4415 points

Hi Collin,

The input signal is from XLR connector, if -1dBFS is recommended for PCM1863, the attenuation by amplifier is needed. Do you happen to know which amplifier is most suitable used as attenuation for XLR signal? Thanks!

Best Regards!

Hao