Part Number: TAC5111
Hello, my team is developing a test board using a TAC5111 codec as the audio interface with ADC and DAC functionality. It is communicating with our DSP processor over an I2S link and we have tested in both DSP master and codec master modes.
Across all configurations and tests we are seeing a common problem of high frequency noise on the DAC output. I will attach screenshots of this pin probed on an oscillisocpe, the general pattern is a random set of +- 20 mV jumps timed exactly to the DAC modulator frequency. I have confirmed this is the source by changing the DAC modulator frequency from 2.8 MHz to 1.4 MHz and observed the transitions of the noise changing accordingly.
Attached are screenshots of time base and frequency base measurements of the output signal path showing the 2.8 MHz modulated noise.
Some other changes we have attempted include, DAC Digital mute (noise persists), DAC shutdown (noise is removed), halving the DAC bias current reference PWR_TUNE_CFG1=0x82, DAC low-power interpolation filter PWR_TUNE_CFG1, high DR/SNR output driver mode OUT1x_CFG1=0xE0, and disabling the PLL CLK_CFG2=0x09.
Any assistance in other areas to look at in debugging this issue are appreciated.
