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TPS7A47: High output noise

xingwitt
Prodigy 140 points
Part Number: TPS7A47

Hi team,

The power supply circuitry referred to the ADS1285EVM. That means I chose the TPS7A47 device as the power supply for my circuit.

On the left is my circuit, layout and output noise, on the right is the ADS1285EVM 's

 

 

 

The device selection is the same, the circuit principle is the same, what makes my LDO voltage output noise much larger than the voltage output noise of the ADS1285EVM?

What can I do to optimize the noise situation？

  • 0
    TI__Mastermind 36265 points

    Hello,

    Make sure you are measuring the output noise of the LDO on each board the same way (it should use a kelvin connection across Vout).  Keep in mind that the layout of the new design may be picking up noise. I would confirm that the capacitors are the same across both designs (manufacturing part numbers if possible, not just values and ratings).  If necessary you can also increase the value of the NR capacitor on the new design to decrease the noise.

    Thanks,

    Stephen