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TPS7A90: Output voltage is the same as the input

Part Number: TPS7A90

I use a TPS7A90 IC to generate 5V from 5.25V. I did the schematics according to the datasheet. I soldered the circuit on the PCB, but instead of having 5V the output voltage is the same as the input voltage. I changed the IC, I modified the input voltage, but the result is the same.

Do you have any suggestions, what is the reason for this and how can I solve it?

Here is my schematics:

Thanks

  • Hi,

    There do not appear to be any issues with your schematic. The internal voltage reference of the TPS7A90 is 0.8 V, so you have chosen your feedback resistors correctly to output 5 V. Furthermore, the maximum dropout voltage for this LDO is 200 mV. Since your headroom (Vin - Vout) is larger (250 mV), the device should be regulating normally. Try varying the input voltage across the entire recommended operating range (1.4 V to 6.5 V). If the output voltage is always the same as the input, it is likely that they were accidentally shorted together during the soldering process.

    Thanks,
    Gerard
  • Hi,

    As it has been several weeks without a reply, I will be closing this thread. If you have any additional questions, you may post at any time.

    Thanks,
    Gerard