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TLV431: Regarding shunt regulator gain and phase margin study

Divakar ethiraj
Prodigy 20 points
Part Number: TLV431
Hi Team
Good day!
This mail is regarding the TLV431 shunt regulator gain and phase margin study.
Currently I am validating the Spice model of TLV431 with respect to datasheet value.
Datasheet info:
Link: https://www.ti.com/lit/ds/symlink/tlv431a.pdf?ts=1713939347533
Simulation info:
Please find the simulation circuit below , so I am currently using the same above Test circuit to validate the spice model. (Tamb:25C)
Simulation output:
We can see here the Gain margin from the datasheet and the simulation output is matching perfectly.
And in the phase margin study we could see there is a deviation from the simulation output (shift) from the datasheet plot.
So can you please check and let me know why this deviation occurs in the phase margin and how to rectify it?
Please let me know if you need any further details. 
Thanks & Regards
Divakar B
  • 0
    TI__Genius 9020 points

    Hello Divakar,

    Can you provide a plot of the simulated phase margin by itself with the phase shift axis labeled? The phase margin follows a different axis than the voltage gain.

    Thanks,

    Walter

  • 0 in reply to Walter Zollinger
    Prodigy 20 points

    Hi Walter

    Good day!

    Yes I understood , I am really sorry for the wrong study.

    In the below image I have corrected it. But here I have one small doubt.

    Left image: Once I matched the simulated value with the datasheet , where the phase degree I got is from 180 to 0 from top to bottom, Where in the data sheet it is inversed, But it matches the plot.

    Right image: I have rotated the datasheet graph and done a 180degree phase shift to the simulation output, and matches the data.

    Can you please help me on this? Whether my analysis is correct?

  • 0 in reply to Divakar ethiraj
    TI__Genius 9020 points

    Hello,

    Your curve is correct as it matches the datasheet. You might have forgotten a negative sign or reversed variables in your calculation causing the phase shift axis to be flipped.

    Best,

    Walter