Is it possible to use this device as a high speed event measurment sensor, I have seen an image of this in a TI presentation but cant find any more application details on this. If so what is the speed limitation of the device and do you have any details on what type and size of coil would be required?
does the target just. Red to be conductive, are there any other restrictions?
Luke,
Event counting is definitely something that is possible for LDC0851. There is an example of this using a rotating gear in section 9.2.1 of the datasheet.
The maximum gear speed for this scenario is described in the following equation
fsensor is specified as follows
and equation 6 is shown here
For the target, you should be able to design with any reasonably conductive material, but highly conductive materials tend to work best. We have a guide regarding the design of the target you can reference here:
https://www.ti.com/lit/an/snoa957a/snoa957a.pdf
As for the sensor coil itself, there are several considerations to take into account. The size of the coil relative to the target being sensed will impact the ability of the device to generate the surface level eddy currents in the target. Also, the size of the sensing coil will impact the required distance between the target and sensing coil. More details regarding the design of your coil can be found here:
https://www.ti.com/lit/an/snoa930b/snoa930b.pdf
Additionally, we have a sensor coil design tool which you may find useful as well:
https://www.ti.com/lit/zip/slyc137
As well as guides for stacked coil design (should you desire this configuration)
https://www.ti.com/lit/pdf/snoa982
And a quick start guide for LDC0851
https://www.ti.com/lit/an/snoa947a/snoa947a.pdf
Thank you,
Scott Bryson
