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TPS7A33: not get expected VOUT

Part Number: TPS7A33

Hello,

Please check schematic here: /cfs-file/__key/communityserver-discussions-components-files/196/TPS7A33.pptx

usage condition is Vin=-5V, Vout=-2.5V

R1 and R2 were calculated with datasheet description, as R1=112.5Kohm and R2=100Kohm. But actual measurement voltage was -2.2V.

What is problem? please give your advise.

Best regards, Katsu

  • Hey Katsu,

    So one of the following things may be happening here:

    1. Your resistor values may be incorrect.

    Have you measured the resistor values on your PCB? We noticed that if you switch your R1 (112.5k) and R2 (100k) values, the regulated voltage would be 2.2V.

    2. Your device may be going into dropout.

    Have you connected the output to a scope to monitor the output? If you happen to be using the device to supply a load, the application may be demanding a higher power dissipation than the device is rated for.

    3. The trace layout may be causing a voltage drop between the point of regulation and the point you are measuring your voltage at.

    Best,

    Juliette