TI E2E Community
Audio Converters Forum
PCM3794A Left/Right line out variation
We use this part in a production board of which we have build approx 50 units so far. For most of the units, the left and right outputs are very closely matched (<1%), but we have found one unit in which they are different by approx 5%.
Our test condition is to play a ~75% full-digital scale 1KHz Sine wave as digital I2S audio into the digital interface and set the PCM3794A to play out with -1.5dB gain level setting for both left and right line (LOL and LOR). When we measure the output on a scope we see that one channel is 5% quieter than the other and this is true if we have 10uF into 10k ohm to gnd or an open circuit on that output. By removing all the other components from the output path of the Line output, we think it must be due to the PCM3794A.
The datasheet gives a typical full-scale output of 1Vrms (page 3), but there are no minimum and maximum values stated, or any idea of the variation between left and right.
Do you have minimum and maximum values for full-scale output (into a given load) and a value for the difference between left and right for the same input?
Unfortunately we do not have min/max data for channel matching for this audio converter. 5% mismatch equals about 0.2dB, which is not unusual for an audio DAC.
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