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TPS7A4701EVM-094: TPS7A4701EVM-094

Sridhar C
Prodigy 10 points
Part Number: TPS7A4701EVM-094

Tool/software:

Hi Team, 

We recently purchased a couple of eval boards(TPS7A4701EVM-094) for TPS7A4701 device from Mouser. As per the datasheet the device should be able to source up to 1A of current but unfortunately even with a simple resistive load of 10 mA, the device seems to go into shutdown mode and delivers only 0V. If the jumper J8 is left open the output voltage is the same as the input voltage, this behavior is different from what is documented in the datasheet.

The ramp-up and ramp-down time seems to be too long even with no load connected. Is there a way to calculate the capacitor values to reduce the ramp-up and ramp-down time?

We have based our designs based on this device, if this is not resolved in the next couple of days we will be forced to redesign with a different LDO. Kindly support at the earliest.


Regards,
Sridhar C
Ciphor 

  • 0
    TI__Guru 50025 points

    Hi Sridhar,

    Have you captured any waveforms that can help understand what you are seeing?

    Sridhar C said:
    As per the datasheet the device should be able to source up to 1A of current but unfortunately even with a simple resistive load of 10 mA, the device seems to go into shutdown mode and delivers only 0V. If the jumper J8 is left open the output voltage is the same as the input voltage, this behavior is different from what is documented in the datasheet.

    Are you saying that with no load the device starts up and regulates, but with a 10mA load the device goes from regulation to appearing to turn off? How do you have the ANY-OUT pins configured? If the ANY-OUT pins are used to set the output voltage, J8 needs to be shorted otherwise R1 changes the set point. 

    Sridhar C said:

    The ramp-up and ramp-down time seems to be too long even with no load connected. Is there a way to calculate the capacitor values to reduce the ramp-up and ramp-down time?

    The EVM comes with a NR cap of 1uF, which is pretty large and will result in a slow startup. Use equation 5 to calculate the startup. 

    Regards,

    Nick