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LDC0851: output voltage for LDC0851

Part Number: LDC0851

For device we  need the output to be switch from 0 to 25-30V .How can we implement?Shall we pullup the output pin to25-30V??

  • Hello,

    The output of the LDC0851 is nominally VDD - 0.4V in the off state (inductance of LREF > LSENSE) and 0.4V in the on state (LSENSE < LREF). Refer to the VOH and VOL specifications in the electrical characteristics table of the LDC0851. Also note that the abs max voltage on the supply is 3.6V, therefore you should not exceed this voltage or damage to the device can occur.

    If you want to translate the output voltage, a simple way could be to connect the output of the LDC0851 to a comparator with a supply voltage of 0V and 30V.

    Regards,

    Luke

  • Dear Sir,

    Thanks for the input.

    If the output is needed to be PNP or NPN open collector.Then can we provide the required???

    Regards

    Seema Joshi

  • Hello Seema,
    The output of the LDC0851 is a push/pull interface. You can connect it to the external circuitry of your choice to achieve 0V and 30V. The example provided above was just showing a comparator. A PNP or NPN implementation is also acceptable.
    Regards,
    Luke
  • Dear luke,

    we have designed  interface LDC0851 .testing the coil design attached coil proxy  working for proximity 3mm.indusctance 20 microhenry

    We are targeting for 5mm proximity so designed another coil with more number of turns as well as wide tracks as per attached coil167.15 microhenry.

    expected inductance with latest coil was more  to have more proximity at 5 mm.How it resulted to less inductance as well well as less proximity.

    Please guide how to design coil between 16-17 mm OD to have 5mm sensing distance.

    coil167.zip

  • Hi luck,
    One more query with coil inductance of 15 micro Henry we are achieving proximity sensing 3mm .our requirement is 5mm sensing,also coil outer diameter diameter is limitation 16 mm to 17 mm.shall we go for series coil with additional layer which will provide 30 micro Henry inductance.
  • dear sir,

    We have coil 15uH which is attached ,we tested ok with LDC0851 interface proximity 2.5 mm.

    What changes we need to do so that we can achieve 5mm proximity.

    Regards

    Seema Joshi0268.coil proxy.zip

  • Hello Seema,
    The switching distance for the LDC0851 is set by the outer diameter of the coil, not by the nominal inductance value. The LDC0851 compares the inductance values for the LSENSE channel and the LREF channel and changes the output state depending on the relationship. Therefore it is important to correlate inductance change versus metal-to-sensor distance for your specific sensor to know where the switching point will occur. I've included some typical graphs in the LDC0851 datasheet to help give a general idea for where this point may occur (figures 7 and 8 of the LDC0851 datasheet). Additionally, we've released a webench tool that can help designing a customized coil for you depending on your input parameters. Please find a link to the webench tool here: www.ti.com/LDC0851Webench
    I've written a blog that walks through a design example here: e2e.ti.com/.../inductive-sensing-make-your-proximity-switch-applications-are-as-easy-as-1-2-3-with-webench
    I should note that for proximity applications, you will get the longest sensing range with a side-by-side coil placement. Stacked coils can be used for PCB space savings, but you will not be able to sense as far by stacking the coils on top of each other primarily because the switching distance is also influenced by the spacing between the LSENSE and LREF coils. I've outlined some of the key factors that influence the switching distance in this thread here: e2e.ti.com/.../2078545
    Regards,
    Luke