• Resolved

LDC1612EVM: Can not get a more stable inductance value?

Part Number: LDC1612EVM


  We were developing a target detecting device with the LDC1612.The LDC1612 EVM is used to make a prototype device for performance evaluating.

  The entire prototype device is shown in the following picture, where CH0 is connected to a coil with a 10cm diameter and 5 turns. An ordinary 510pF ceramic cap (not COG/NPO) was soldered to the C10 of the EVM board. The original on-boared PCB coil of CH0 has been cut off from the connection point.

  We've gotten the inductance data outputed from the EVM GUI Tool and we found the LDC1612 to be very sensitive, as it could measure the inductance changes in the level of several picohenries(pH), which is attractive to us. However, the output inductance data is not very stable in pH level, and we could not solve this problem. As shown in the following pic, the inductance value is drifting in a level of tens and hundreds of pH as time going by.


The configurations are shown bellow:


 What cause the inductance to drift? How to improve to get a more stable output?

Best regards

  • The LDC1612 is quite sensitive and could be reacting to a number of things:
    - subtle changes due to movement of your wires (ex. vibrations, movement, etc)
    - slow temperature changes
    - reaction to an oscillator drift

    The goal should be to improve the SNR of your sensor as much as possible so that your signal is above these small changes.