Hi,
Can somebody help me? I would like to use the PCM1796 with passive termination. I need 0,4Vpp differential output voltage. I looked for but I didn't find any details about the current segment DAC of PCM1796.
The output of the DAC between is between -1,5m..-5,5mA I thought it is a current sink DAC. But in the recommended Application Circuit (datasheet page34) U1 output voltage is -1,23V...-4,51V to the ground that means for me the converter is an current source DAC. What is the "truth" or what did I missed?
Is the passive termination possible like on the picture or connect to VCC?
Hi, Tibor,
Check out page 55 of the d/s. It discusses output current.
Unfortunately, we don't have any experience doing what you're trying. You are going to low-pass filter the signal somewhere in your design. And, I'm a little worried the output current source is not going to be as linear as you'd like driving such a low resistance.
-d2
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Don Dapkus
Audio Applications Engineering Manager
Dallas, TX USA
Thanks for the quick answer.
Tibor
Hi Don!
pp 55 of the datasheet points to the schematic of figure 36. That one shows a couple I/V converters with the 5534. Those I/V converters are meant to present a virtual ground node to the PCM1794 / PCM1796, and as such, 0 volts and (theoretical) zero ohms.
May be that you meant that the existence of voltage other than zero would make the current source less linear ?