Other Parts Discussed in Thread: TINA-TI
Tool/software: TINA-TI or Spice Models
Hello everyone,
I'm trying to determine the ROC of an Op-amp used in a Right Leg Drive for an ECG I'm designing. I'm fairly new to the stability analysis by means of breaking the loop with an inductor and a capacitor and so forth, so I've decided to follow some simple examples so as to not get ahead of myself. The circuit I'm simulating is this one:
And this is the Bode plot (pre-processing) they obtain:
As you can see, n2 at 10 Hz has a gain of approximately 77 dB, n3 is constant at 0 dB and n1 starts off at -40 dB.
However, when I perform the same analysis, I get the following results.
n1 and n3 behave exactly the same as in the example, but n2 does not.
This is my schematic:
I've been staring at it for hours, comparing it to the one in the example and I haven't found anything that could prompt this monumental difference. I don't know whether I am too tired to notice the subtle error that might be there or if it's something completely different that I haven't taken into account. Needless to say, the Aol is utter nonsense using this results.
In both cases, the AC transfer characteristic is performed from 10 Hz to 10 MHz, with 100 data points. The example is from the "Operational Amplifier Stability, Part 2 of 15: Op Amp Networks, SPICE Analysis" document from TI.
Thank you for your attention.
