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TINA/Spice/INA240: INA240

Chandrashekhar Shitole
Prodigy 20 points
Part Number: INA240
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Support Path: /Tools & software/Help me with an issue/Other Models & Simulation Tools/

Hello All,

I am using spice model given at TI site for INA240. As per data sheet offset voltage for INA240 is +/- 25uV but in actual simulation without connecting any input i am getting it as output as 53mV.(expected will be 25uV multiplied by Gain which is 50 in my case)

How it is so?

Kindly revert back with your thoughts.

Thank You.

Regards,

Chandrashekhar

 

  • 0
    TI__Mastermind 27410 points

    Hello Chandrashekhar,

     

    Please provide a few more details-

     

    How are the reference pins connected in your schematic? Is the output monitored with respect to ground? By “without connecting any input”, do you mean the input pins are floating? What about the power supply pin? All input pins should be connected to known voltages if you haven't done so. 

     

    From the below circuit I constructed, I don't see the problem. But if you continue to have difficulty, please post your simulation circuit here so we can take a look.

     


     

    Regard, Guang

    Apps Support-Current Sensing

  • 0 in reply to Guang Zhou
    Prodigy 20 points

    Dear,

    Thank you for your prompt reply. 

    Following is the circuit i have constructed,

    I want use it in ground reference output mode so I have connected REF1 and REF2 to gnd.

    Simulation result i have obtained as follows - 

    Output shows continues offset of 53mV.

    One more question I have, though we are not giving any reference why output always start from 2.5V.

    Kindly revert back with your thoughts.

    Thank You.

    Regards,

    Chandrashekhar

  • 0 in reply to Chandrashekhar Shitole
    TI__Mastermind 27410 points

    Hello Chandrashekhar,

     

    Thank you for the schematic.

     

    Swing to ground should be no more than a few millivolts. The output should not start from 2.5 either.

     

    Apparently this is a modeling problem, but we’ll find out what happened our modeling expert will be working on it. So far it appears to me that there is a newer/updated version that was never released.

     

    Regard, Guang

    Apps Support-Current Sensing

  • 0 in reply to Guang Zhou
    TI__Genius 14825 points
    Chandrashekhar,
    The modeling team has been working on this and we will release a new model next year. I don't have a definite date at this time. Is there anything else we can help you with at this time?