Hello,
Our customer is using a 5V TPS61071 boost converter near the PCM1803A and they are seeing noise coupling.
They believe there is magnetic coupling between the 5V switching inductor and ADC.
The noise appears in the ADC even with inputs terminated and gets better with the inductor moved away.
The noise only occurs at a specific battery input voltage range for each particular board.
Inductor is Shielded (coilcraft EPL3015-682ML ) and they have tried many inductors without removing the noise.
Shielding the inductor with metal does not affect the noise. Mu metal completely removes the noise.
There are 2 different layouts which show the same behavior.
The questions they have are:
1. The 5V boost TPS61071 converter runs at 1.2MHz, is this an important frequency for the PCM1803A?
2. Are there loops in certain areas of the PCM1803A that may be more susceptible to magnetic coupling?
Thanks, Keith
