OPA2333: OPA2333

Part Number: OPA2333
Other Parts Discussed in Thread: OPA391, OPA350, OPA320, , TINA-TI

Tool/software:

Hi Team,

We are using this Amplifier part P/N: OPA2333AIDRBT  in our current design, we got some comments from reviewer on stability.

Please provide the stability report on the same for below mentioned cases:

1. Stability report at 50% Load

2. Stability report on 100% Load

3.Stability report on step load from 10% to 90%

We attached out design schematic also for your reference

Please share any stability analysis report you have done

Awaiting for your response

Thanks and Regards,

Prem Arya

Schematic_OPA2333.pdf

  • Hi Pem,

    1. Stability report at 50% Load

    2. Stability report on 100% Load

    3.Stability report on step load from 10% to 90%

    What is the load?

    This is OPA2333 buffer amplifier, where the output is following the input. The feedback cap and resistors are not needed. It has the plenty phase margin as it is configured, and it should be stable. 

    Please let me know the load types and I will check it out for you. 

    Best,

    Raymond

  • The output pin of the amplifier is connected to input of ADC and the maximum input current for ADC  is 10mA so, i think we can consider 10mA is max load

  • Hi Pem,

    OPA2333P is micro power precision op amp, and it is unable to supply ±10mA of current. You may consider or OPA391, OPA320 or OPA350  or others for the application.  

    Please let me know the op amp that you are going to select. We need to revaluate the op amp stability case by base in each op amp selection. 

    This is one of the dual feedback compensation approach, if the capacitive load is larger. 

    If you have other questions, please let me know.

    Best,

    Raymond

  • Hi Raymond, 

    we have simulated our current design on the TINA-TI tool and we are trying to see the Phase margin and Gain margin , but we are not getting the Phase margin , basically, we are not getting waveform at 0db gain but it should cross the 0db gain, waveform itself starting after 0db.

    we are applying AC input as 4.5V unit step .

    Can you please guide me where we are wrong or can we get simulated results from your side that will help to know the stability

    Here I am attaching here our simulated model also here for your reference

    Thanks and regards

    Prem Arya

  • Hi Pem,

      For AC Analysis, you need to remove the LPF filter at the input front. The 15.9kHz LPF does not affect the AC stability. 

    Please check out our Precision Op Amp Lab Series Training video. 

    https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps.html

    Enclosed is the above AC stability simulation. 

    OPA2333 AC stability Analysis 06062024.TSC

    BTW, OPA2333P is unable to source or sink up to 10mA. This is micropower precision op amp. 

    If you have additional questions, please let me know. 

    Best,

    Raymond