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TPS755: Values of R1 and R2 & Impedance seen on the output

high speed guy
Expert 3505 points
Part Number: TPS755

Hi,

For the TPS75525 (2.5V fixed) can you tell me the value of R1 and R2 internal to the device?

For the TPS75515 (1.5V fixed) can you tell me the value of R1 and R2 internal to the device?

For my application I need to understand the impedance as seen at the output of the LDO.

Thank you,

HSG

  • 0
    TI__Mastermind 37005 points

    Hello high speed guy,

    The output impedance of the LDO is provided for these devices in the datasheet, and is a function of load and frequency.
    Please see the following plot from the datasheet.

    Thanks,

    - Stephen

  • 0 in reply to Stephen Ziel
    TI__Expert 3505 points

    Hi Stephen,

    Thank you for helping us to understand the active impedance of the output.  It will still be helpful to know the values of R1 and R2 as seen at the output when the device is off.   Is it possible to locate this information?

    Thank you,

    HSG 

  • 0 in reply to high speed guy
    TI__Mastermind 37005 points

    Hello HSG,

    I will make measurements on unpowered units and provide you with the results.
    The EVM's do not have the 1.5V powered, so I have ordered samples.
    In case the EVM's are not in stock in our lab, I have also ordered samples.

    Please allow 5 business days for the samples to arrive, then another business day for the measurements.

    Thanks,

    - Stephen

  • 0 in reply to Stephen Ziel
    TI__Expert 3505 points

    Hi Stephen,


    Thank you for the update.  Just to be certain, we will need the same measurement for the 2.5V version as well.   We look forward to receiving the data later in the week.  

    Thank you,

    HSG

  • 0 in reply to high speed guy
    TI__Mastermind 37005 points

    Hi HSG,

    Understood. I ordered samples of every variant of this component, and 2 EVM's.
    I should have data for you even for variants you did not request.

    Due to the shipping time it will not happen until next Monday, however if it arrives early I can take the data this week.

    Thanks,

    - Stephen

  • 0 in reply to Stephen Ziel
    TI__Mastermind 37005 points

    Hi HSG,

    I measured the following linear regulators without any additional components.
    I used a calibrated DMM (HP 34401) and connected the positive lead of the DMM to Vout, and the negative lead of the DMM to GND of the LDO.

    TPS75533KTTR: 124k ohms
    TPS75533KC: 124k ohms
    TPS75525KC: 125k ohms
    TPS75518KC: 123k ohms
    TPS75515KC: 124k ohms
    TPS75501KC: 1Meg ohms

    Thanks,

    - Stephen