This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS7A47: (very) low frequency noise - any data available?

Part Number: TPS7A47

Hello, looking for a LDO for an application where the LF noise also matters (0.01-10 Hz) the graphs in datasheet are 10 Hz - 1 MHz and the charts suggest that it will be rather flat at low frequencies..? Please do you have any data supporting this? 

The LDO will post-regulate an output of a step-down converter and power-up an H-bridge switching circuit running at 14 kHz (we need the voltage accross the H-bridge to be as stable as possible ) 

The operating conditions would be like Vout = 5.5V, Iout=200mA, constant Vin = 6V from the DCDC, constant temperature...

Thank you

Best regards,

 Vojtech

  • Hi Vojtech, 

    Our AC data including PSRR and noise starts at 10Hz and this is also an industrial standard. Here is an app note that discusses noise filtering with less than 10Hz. 

    Regards, 
    Jason  Song

  • Dear Mr. Song,

    thank you for the answer and the pdf. I am not going to construct that 0.1-10Hz bandpass, but as soon as I will have the pcb I will try to measure "something" with agilent 34401 and with proprietary high dynamic range digitizer. I will post the results. I have hoped for some info before I will finish the pcb design so I could modify the design appropriately.

    Best regards,

       Vojtech

  • Hi Vojtech, 

    Thanks for your feedback. Please let us know your measurement results and if you have trouble with the measurement, we are here to help.  

    Regards, 
    Jason