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OPA2205: TINA Simulation error with DRV103

Sadashiva Kamath
Expert 1165 points
Part Number: OPA2205
Other Parts Discussed in Thread: OPA192

Hi,

I created difference amplifier of gain 7.5.

Input voltage is 335mV. But, I'm getting output voltage of 7.55V. Expected output voltage was 2.51V,

What is root cause of this error?

  • +1
    TI__Guru 56281 points

    Hi Sadashiva,

    The root cause is that you violate the common mode voltage requirements in OPA2205. For a single supply voltage, the Vcm needs to be above 1Vdc.

    It would be ok if you use dual supply voltage rails as an example below. 

    OPA2205 Diff Amp 09092021.TSC

    If you have additional  questions, please let me know. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    Expert 1165 points

    Thanks Raymond for prompt response,

    I do not have negative power supply in my design. 

    I have replaced OPA2205 with OPA192 and added diode, capacitor circuit at the output of OPAMP.

    • I'm getting convergence problem with OPA192 when diode, capacitor and resistor added. How to fix this? .tsc file included. Error disappears when I change R8 from 10K to 12K

    Same error is not seen with OPA2205 when diode, capacitor and resistor (10K) added.

    sbvc004b_OPA192.tsc

  • 0 in reply to Sadashiva Kamath
    TI__Guru 56281 points

    Hi Sadashiva,

    The issue seems to be that particular schottky diode and 100nf capacitor. I changed to Si Diode and different schottky diodes, the convergence issue went away. 

    If you have to place 100nf capacitive load at the output, you may require to compensate the OPA192, so that the circuit can drive a capacitive load. 

    If you have additional questions, please let me know.

    Best,

    Raymond