SBAS495D June 2010 – August 2021 PCM9211
PRODUCTION DATA
The PCM9211 operates under the system clock (SCKI) and the audio sampling clock (LRCK). The PCM9211 does not require a specific phase relationship between audio interface clocks (LRCK, BCK) and the system clock (SCKI), but does require the synchronization in the frequency of LRCK, BCK and SCKI. This requirement allows SCKI to be provided elsewhere than from LRCK and BCK.
LRCK and BCK require synchronization at all times.
If the relationship between SCKI and LRCK changes more than ±6 BCKs as a result of jitter, a frequency change, and so forth, the internal operation of the ADC stops within 2/fS, and the digital output will be ZERO codes until resynchronization between SCKI and LRCK and BCK is completed. Real data begin to be generated a period of tADCDLY3 later.
Changes or drift less than ±5 BCKs do not cause any issues with the device. Figure 7-7 shows the ADC digital output when synchronization is lost.
The ADC output, DOUT, maintains its previous state if the system clock stops.