Tool/software: TINA-TI or Spice Models
Can someone help me with the following question from my customer:
What I was doing that prompted the question was designing a stereo DAC output circuit with a pair of dual OpAmps.
I've read and studied the DAC and OpAmp data sheets, and several TI application notes around this topic, some very helpful.
I wanted to split the output of the OpAmp I/V stage to 'drive' two high-impedance line-level outputs via duplicate OpAmp output stages, and wanted to use TINA to analyze the THD and Noise and assure it was not impacted by either the noise of a higher individual output stage input impedance (set by the input resistors to the output stage) or the distortion of driving a lower combined (resistor) impedance of two parallel output stages. Which is a balancing act.
When doing this sometimes it seems to work correctly, but I sometimes get THD numbers which I do not believe. And the THD changes dramatically waiting different numbers of source cycles to start. Etc. There is not much visibility into the tool unfortunately.
So I wanted to understand how the tool works in more detail to be able to judge all this.
Regards,
David
