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OPA171: Bipolar and CMOS Vos temperature drift performance difference

Part Number: OPA171

Hi team,

Here is a confusing item of Amplifier temperature drift.

From below training slide page 7, there is a Vos temperature drift Bipolar and CMOS comparison.

What is the root characteristic leading to the different Vos temperature drift performance?

Best regards,

Mia Ma

  • Hey Mia, 

    Welcome to e2e! It has to do with the "physical inner workings of bipolar and MOSFET transistors." This application note by Marek Lis goes into some more detail: 

    All the best,

  • Hi Carolia,

    Thank you for your reply at first.

    And actually there is no further explanation of the reason leading to the different, physical inner-workings of bipolar and MOSFET transistors.

    the Vos is caused by the mismatching of the symmetry input stage, what the different key characteristic between bipolar and MOS?

    If the Ib of bipolar and Vgs of MOSFET different temperature drift leading to this results?

    Please give comments if convenient, Thank you a lot.

    Best regards,

    Mia Ma

  • Hello Mia, 

    From all the TI resources, I have not been able to find more detail than just "inner workings of the transistors." 

    However, I did find this presentation for Berkeley that goes into a lot of detail between the different topologies: 

    Why do you need these details... what is the problem that is being solved?

  • Hi Carolia,

    Thank you for your reply and reference files.

    Actually not for specific question, just a tech deep-dive confusing.

    Thank you.

    Best regards,

    Mia Ma