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OPA192: TINA-TI Transient DisplayTime Setting

Liu Songlei
Prodigy 10 points
Part Number: OPA192
Other Parts Discussed in Thread: TINA-TI, OPA187, , OPA828

Tool/software:

Hi, Dear Team

     

If  the Display time was set as 0~100ms,  Zero initial Values

the result looks like this

If  the Display time was set as 0~800ms,  the result looks Normal 

  

Is there something wrong with the circuit or Tina-Ti setting？

Thanks！

  • 0
    Prodigy 10 points

    the Tina-TI  Version is the latest

  • 0 in reply to Liu Songlei
    TI__Guru 60031 points

    Hi Songlei,

    This is the Tina 9.3.20 is the latest FREE version from TI. Tina's latest version is 14, and it costs approx. $1500. However, this is what I use and it is good enough for typical tech. support. 

    I am unable to duplicate your issue. Please show me the issue and send me the file. 

    OPA192 + OPA187 Step Transient 12062024.TSC

    BTW, the OPA187 op amp is not necessary and it is used as comparator. I am sure that what you are trying to do. OPA187 is used as composite amp, the it needs to have its own feedback or something. OPA192 is able to source or sink current higher than OPA187. Both slew rate and BW are higher in OPA192 than OPA187. So I do not understand what you are trying to do. Please clarify. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    Prodigy 10 points

    3-Aol-with aux-OPA192 +OPA187 AOl.TSC

    Hi,Raymond

    Thank you for your answer. 

    I was trying to build  a circuit  to measure  the AOL of  the amp.  OPA192 was used as the DUT and OPA187 as AUX amp.

    I tried to replace OPA187 with OPA828, the 'End dsplay' time can be  much shorter.    

  • 0 in reply to Liu Songlei
    TI__Guru 60031 points

    Hi Songlei, 

    I need to understand what you are trying to do. As it is configured, it is typically used as signal conditioning and threshold hold detection applications. Is this what you intended?

    The OPA192 has GBW of 20MHz, with the feedback the gain is approx. Ao1 = 2000 V/V (GBP formula). The 2nd op amp is configured as comparator, so the output stage will go high or low vs. a GND reference (Vin- = GND). This is not a linear op amp configuration because of the 2nd stage configuration. 

    If the 2nd stage is a linear circuit (need a feedback), the overall gains will be A_total_ol = A_o1*A_o2 . So I need to understand you are trying to do. 

    Here is our video training series and I can simulate the Aol, if I understand what you are trying to do. 

    https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps.html?keyMatch=op%20amp%20precision%20video%20series&tisearch=universal_search

    Liu Songlei said:
    I tried to replace OPA187 with OPA828, the 'End dsplay' time can be  much shorter. 

    Yes, this is correct. If you place OPA828 and replace OPA192, it will be even faster. If the 2nd stage has to be a comparator, then you just need to place a comparator instead of OPA187. 

    If you have other questions, please let me know. 

    Best,

    Raymond