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LDC1612 / remote sensing

K.Yaita
Guru 29720 points
Other Parts Discussed in Thread: LDC1612, LDC1612EVM

Hi Team,

I understood LDC1612 supports remote sensing.
On the other hand, the datasheet shows the following.
>10.1 Layout Guidelines
>Avoid long traces to connect the sensor to the LDC. Short traces reduce parasitic capacitances between sensor
>inductor and offer higher system performance.

May I have your advice how to achieve remote sensing for LDC1612?
(Is there any recommended solution for remote sensing?)

I would also like to know if it is possible to connect distributing cable between sensor coil and LDC1612.
Is there any length restriction of the cable?

Best Regards,
Yaita / Japan disty

  • 0
    Guru 29720 points

    I would also like to know the recommended cable.
    Do you recommend STP cable than UTP cable?

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Genius 13650 points

    Hello Yaita-san,

    the LDC tools spreadsheet  has a 'Remote Coil Length' tab which calculates the maximum sensor cable length for a given device and oscillation frequency. I recommend using a UTP cable and not an STP cable. STP cables add a lot of capacitance which limits performance of the LDC. The use of UTP cables is recommended.

  • 0 in reply to Ben Kasemsadeh
    Guru 29720 points

    Hello Ben-san,

    Thank you for your valuable feedback.

    I tried setting UTP cable(about 15cm) between sensor coil and LDC1612EVM, then confirmed the inductance value of LDC1612 changed significantly when put my finger closer to UTP cable (not touched yet).
    Is it influence of parasitic capacitance?

    I am concerned about noise tolerance in remote sensing solution.

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Genius 13650 points

    Hi Yaita-san,

    yes, what you are seeing is an effect of parasitic capacitance. In the system, it is important to tie down or glue down the cable to prevent movement and change the capacitance as a result. Additionally, consider increasing the sensor capacitor value, so that the impact that the parasitic cable capacitance has is small compared to the discrete sensor capacitor.