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  1. #1
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    TI TINA simulation with AD8603 over voltage not picking up

    Hi I am new to TINA TI simulation world. I used one of their example circuit 0-10V @ 10mA DAC Interface Circuit ( see attached)

    TINA TI.zip



    I noticed that original OPAMP in the example circuit was OPA251 and it is powered using 32V DC (single supply) in simulator & this supply is within the limits of what opamp cant work with (up to 36V DC)

    & then I ran DC transfer Analysis & I get nice 0 to 10V Output for 0 to 1V Input

    I then used Analog devices Website to download SPICE model for AD8603

    I created new Macro for this and saved (also attached in above folder)

    I replaced the OPAMP in the example circuit.

    Now this OPAMP (AD8603) works upto maximum of 5.5V. But I left the V+ in my example circuit as 32V just to see if I see any clipping at the output or any other errors. But I was surprised to see that the circuit simulates "perfectly fine" i.e., not showing any distortion even though it is rated for 5.5V maximum.

    Is it normal to expect like this in SPICE simulation? How do we normally catch the obvious user-errors of over-voltage supply when simulating (i.e., if I am using the supply out of range of what component (opamp) is specified at)?

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  2. #2
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    Re: TI TINA simulation with AD8603

    Hi,

    Many simulators don't care about specified power supply range.
    Don't try the same at a real circuit.

    A simulation does not replace reading the datasheet.

    Klaus
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    Re: TI TINA simulation with AD8603

    From what I have heard from application engineers, they will only model the main features of the device in its spice model.
    In the datasheet of the opamp you chose, the main features are low noise, low power, low offset etc which are more likely to be modeled rather than the limited supply range which is not really a feature.

    If you chose a fancier opamp with over voltage protection and features of that sort, then they are more likely to model the errors when being forced a higher supply voltage.
    -- Bilgotidia Fertiganed



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