Other Parts Discussed in Thread: PCM1754, PCM1753-Q1
The problem is that if mute pins are turned off, the bottom noise will be there. No matter whether IIS is configured or not, the noise will be slightly reduced by short circuiting tp74 to the ground. Now please consult you,
1: What is the reason for the noise when IIS is not configured?
2：After configuring IIS, the noise becomes louder. What is the possible reason?
The following is the measured waveform. If in doubt, communicate in time. thank you.
B40 current status ：SCK high level, BCK high level, data low level, lrck high level. No noise
C52 equivalent configuration：SCK high level, BCK high level, data low level, lrck high level. Bottom noise
Yellow is the TP72 waveform, and blue is the 8-pin output of PCM1754.
LRCK：
Tp74 grounded
DATA
BCK
SCK
Tp74 grounding
Tp74 ungrounded
