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Original question:

OPA134: About OPA134 specifications

OPA134: Difference in Laser Trim Between Rev.A and Rev.B

miho komatsuda
Prodigy 50 points
Part Number: OPA134


Dear technical support Team,

In the recent PCN for OPA134, I noticed that pins 1 and 8 have been changed to NC, with the explanation that external trimming is no longer required due to laser trimming.

However, the Rev.A datasheet also mentions laser trimming.

Could you please clarify what specific differences exist between the laser trim implementation in Rev.A and Rev.B? For example:

  • Has the trimming process or accuracy changed?
  • Are there any improvements in offset voltage or drift performance?

 image.png

Thank you for your support.

Best regards,

M.Komatsuda

  • 0
    TI__Mastermind 26325 points

    Hello, 

    • The trim pins on op amps go back to a time where laser-trim and package-trim were not available and/or not commonly used. This is why the original device had trim pins. On modern precision amplifiers this feature is not needed because the op amp offset is trimmed internally and is very accurate. This laser trim is applicable to the new revision.  
    • Op Amp Offset Voltage and Bias Current Limitations covers details on laser-trim and package trim in case you would like more details.

    Best Regards, 
    Chris Featherstone

  • 0 in reply to Chris Featherstone
    Prodigy 50 points

    Hi,

    Thank you for your response. I would like to organize the information to ensure my understanding is correct.

    ①I understand that both Rev.A and Rev.B use laser-trim. Is my understanding correct?

    ↓Rev.A

    ↓Rev.B

    ②Rev.A does not use package trim. Is my understanding correct?

    ③Please tell me the difference in laser trimming between Rev.A and Rev.B.

    Thank you for your support.

    Best regards,

    M.Komatsuda

  • 0 in reply to miho komatsuda
    TI__Mastermind 26325 points

    Hello,

    The comment that the input offset voltage trim pins were removed because the device is laser-trimmed is not accurate for this device.  For other revised devices this will be true as the offset is reduced to a point where the trim pins are really unnecessary.  For this device, however, the intent is for audio applications so we do not trim the input offset voltage.  The device is trimmed for other parameters, but the specific details on what is and is not trimmed is proprietary.  For many die revisions the external Vos trim pins and associated internal circuitry are removed because most customers no longer use this feature.  That is, manually adjusting an external potentiometer is not cost effective when compared with just purchasing a low offset device.  Sorry for the inconvenience, but this device and many modern amplifiers no longer include this option.

    Best Regards, 
    Chris Featherstone

  • 0 in reply to Chris Featherstone
    Prodigy 50 points

    Hi,

    I understand that the external Vos trim pins and the associated internal circuitry have been removed from the OPA134 because most customers no longer use this feature.

    By the way, it seems that the PCN details vary depending on the package, but is it correct to assume that the offset trim pin was removed from all OPA134 devices for the same reason? 

    Currently, the customer is using the OPA134PA.

    Thank you for your support.

    Best regards,

    M.Komatsuda

  • 0 in reply to miho komatsuda
    TI__Mastermind 26325 points

    Hello, 

    miho komatsuda said:
    By the way, it seems that the PCN details vary depending on the package, but is it correct to assume that the offset trim pin was removed from all OPA134 devices for the same reason? 

    Yes your understanding is correct. 

    Best Regards, 
    Chris Featherstone