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TPS7A84A: LDO for Dual Supplies OPA

Ben Huang1
Intellectual 575 points
Part Number: TPS7A84A
Other Parts Discussed in Thread: TPS7A39, TPS7A33, TPS7A47

Sir

 

I’d like to take TPS7A84A which is low noise LDO, being suitable to power the sensitive device as high speed OP amplifier

 

Dual supplies are required for our application, could you please help to confirm whether the following connection is correct or not? Or there is any other LDOs can meet our dual supplies application?

 

 

 

LDO for Dual Supplies OPA.pptx

Any suggestion and comment is welcome

 

 

Thanks

Regards

Ben

 

  • 0
    TI__Expert 4350 points
    Hi Ben,

    Yes, your configuration will provide your positive and negative rails for your amplifier: VS+ and VS-.

    However, I recommend a negative LDO for the VS- rail, and use a negative power supply input. This will allow for a common ground reference for the power supplies outputs and LDOs. TI has several low noise negative LDOs and dual positive and negative LDOs.

    What are you requirements for Vin, Vout, Iout for the VS+ and VS- rails?
  • 0 in reply to Eric.Preiss
    Intellectual 575 points
    Hi Eric

    Thanks for comment!

    For high power application, VS+ and VS- will be up to +15V and -15V respectively
    Otherwise low power one required down to 2.5V and -2.5V.
    Souring and sinking current of OP amplifier is less than 500mA

    Could you please help to suggest the dual positive and negative LDO?


    Thanks
    Regards
    Ben
  • 0 in reply to Ben Huang1
    TI__Expert 4350 points
    Hi Ben,

    TI's dual TPS7A39 LDO is limited to 150 mA for each output. You will need to use a separate negative LDO.

    For the negative LDO, I recommend the TPS7A33.

    The TPS7A84A will not work for your high voltage application. I recommend the TPS7A47 instead.
  • 0 in reply to Eric.Preiss
    TI__Expert 4350 points
    Hi Ben,

    I haven’t heard back from you. I’m assuming you were able to resolve your issue. If not, just post a reply below or create a new thread if the thread has locked due to time-out.