hello,
I'm trying to compare noise performance of 3 similar Single ended to differential circuits.
The basic circuit is always the same, just the amplifier itself is changed See SE2DIFF_LM6172_LM7372_LT1364.EMF in Word document
case 1 uses LM7372
case 2 uses LM6172
case 3 uses LT1364 (from LINEAR)
See comparative noise performance.emf in Word Document
Case 1 noise analysis from TINA-TI (Version 9.300.244 SF-T) gives quite expected results. the 1/f noise increase of the Amplifier is clearly observable
Case 2 gives strange results : No 1/f noise and a very strange noise increase above 50kHz !?
Case 3 is also very strange resulting in flat & very high noise.
If I run a similar noise analysis with LT-SPICE, the results look much more like expected. see SE2DIFF_LT1364.pdf
Questions :
Why is case 2 (LM6172) so strange ?
Why is case 3 also so strange and so different from LT-SPICE ? I did import the model from LINEAR into TINA-TI
Thanks for your anwer