• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 31 subscribers
  • Views 488 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

LDC1000 trouble at low frequency

ivan gehin
Prodigy 40 points

Hello,

I am facing a strange behaviour using a LDC 1000 , driving a wire wound coil.

My coil has an inductance value of 4.8mH and a serie resistor value of 20 ohms.

I put a LC tank capacitor value of 4700pf, which lead to a resonance frequency equal to 33508 Hz and a Rp equal to 51 Kohms. Both value are in LDC1000 operating range. So far, so good.

However I struggled a lot to try finding a correct filter capacitor value (Cfb) as described in datasheet, and I am still unable to find a correct value for having a 1V peak peak value as explained.

My problem is that R and L measures are a lot noisy (spikes) and inconsistent (I use an EVM module).

What am I doing wrong ?

I suspect the LDC not being able to handle such large inductance.

Any idea ?

  • 0
    TI__Genius 14270 points

    Hello Ivan.

    We have updated instructions in the latest version of the LDC1000 datasheet (rev c). Have you followed the instructions in this datasheet?

    You may also have an issue with the power supply bypassing for the LDC1000. Please provide the LDC1000 register settings, and if possible, scope plots of the sensor signal and the CFB pin.

    Regards,

    Chris O