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Original question:

TINA/Spice/LMG3410R070: Operation in third quadrant

LMG3410R070: Operation in third quadrant

Kousik Ghosh
Prodigy 90 points
Part Number: LMG3410R070

Can you please elaborate the third quadrant operation of LMG3410R070 and provide the Vsd vs Isd curve variation with Vin. 

  • 0
    TI__Intellectual 805 points

    Hello Kousik,

    Thanks for your interest. The explanation on third quadrant operation is given in Section 8.1 in the datasheet of LMG3410R070. The Vsd vs Isd curve is also provided in Figure 4 of the datasheet. I'm not very clear on what you mean by Vin. Could you explain it further?

    Thanks,

    Serkan

  • 0 in reply to Serkan Dusmez
    Prodigy 90 points

    By Vin I mean the logic pulse input to the IN pin. Which is to be varied between 0 & 5 V. Figure 4 shows the curve for IN =0V . I want to know the curve for IN=5V. Section 8.1 describes the 3rd quadrant operation, when GaN is turned OFF. I want to know the  source- drain voltage  drop when GaN is ON.

  • 0 in reply to Kousik Ghosh
    TI__Intellectual 805 points

    Hello Kousik,

    When IN=5V, the device turns on and shows a resistive behavior in the linear region of operation. You can see the waveform in Figure 3. The gray line in that figure shows the OCP limit. Once the device current goes above this limit, OCP block will cease operation. 

    The RDSon will have a temperature dependence and increases as the junction temperature goes up. This behavior is also shown in Figure 5.

    Please let us know if you need more information.

    Regards,

    Serkan

  • 0 in reply to Serkan Dusmez
    Prodigy 90 points

    Figure 3 shows the first quadrant characteristics. I want to know the third quadrant characteristics when IN=5V. (Figure 4. shows the third quadrant characteristics at IN=0V). Can you please elaborate this ?

  • 0 in reply to Kousik Ghosh
    TI__Intellectual 805 points

    Behavior of GaN when Vin=5V when current is negative, is same as 1st quadrant operation. There is no offset voltage drop, but just Rdson. You can check this from Figure 4 of SNOAA36 app note.

    Thanks,

    Serkan

     

  • 0 in reply to Serkan Dusmez
    Prodigy 90 points

    Well, but the pspice model of LMG3410R070  released by you does not agree with the characteristics shown in Figure 4. of SNOAA36. In the above mentioned model, there is a continuous offset voltage drop of 7.5 V when operated in third quadrant. Also there is no dependency on Vin when operated in third quadrant (pspice model). Please see to the matter and let me know, whats the problem in the pspice model.   

  • 0 in reply to Kousik Ghosh
    TI__Intellectual 805 points

    Hello Kousik,

    I thought you were referring to 3rd quadrant when IN=0V. There shouldn't be any offset issue when IN=5V. I'm investigating the issue with the pspice model. I will get back to you with an answer soon.

    Regards,

    Serkan

  • 0 in reply to Serkan Dusmez
    TI__Intellectual 805 points

    Hi Kousik,

    New model has been released on July 12th. Please download the newer version.  There shouldn't be any offset issue when IN=5V. If you still experience problems, please let us know.

    Regards,

    Serkan

  • 0 in reply to Serkan Dusmez
    Prodigy 90 points

    Thanks. I checked the revised PSPICE model and its working fine. The vsd voltage drop irrespective of IN voltage is removed. It is operating as expected in third quadrant.