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FDC1004: Multiple FDC1004 devices .

Jurgen Ooghe
Prodigy 35 points
Part Number: FDC1004
Other Parts Discussed in Thread: LDC2114, FDC2214

For a project I want to use multiple FDC1004 devices because I need more the 4 channels. Are the devices influencing each other measurements?

  • 0
    TI__Expert 8050 points
    Hi Jurgen,

    This will depend on the sensor setup in your system. Also, the FDC1004 has only one I2C address, you may need to mux the I2C for multiple devices.

    You may also use FDC2214 or LDC2114, which has two I2C addresses.

    Regards,
    Yibo
  • 0 in reply to Yibo Yu
    Prodigy 35 points

    Hi Yibo,

    Can you give more detail on"depend on the sensor setup"? I have to measure capacitance change on 16 area's at the same time. These 16 area's are all located in an square of 4cm by 4cm. Will one,area sensed by chip A be influenced by chip B which is sensing an other area. I will implement multiple I²C masters in an FPGA so I can address all the devices in parallel.

    BR,

    Jurgen

  • 0 in reply to Jurgen Ooghe
    TI__Expert 8050 points
    Hi Jurgen,

    The sensor layout definitely plays a role. In addition, the type of target object you are trying to sense, e.g. size, material, distance, etc., will affect how it interacts with the sensors. If there is fringing capacitance between them, then some channel may be influenced by a nearby channel. You may need to do some prototype testing to check the results.

    Regards,
    Yibo
  • 0 in reply to Yibo Yu
    Prodigy 35 points

    In my design I will have a 5cm connection to the sensing area. The connection trace will be very thin and will introduce a serie resistance of +/- 500 Ohm. What would be the effect on the capacitive measurement?

    KR,

    Jurgen

  • 0 in reply to Jurgen Ooghe
    TI__Expert 8050 points
    Hi Jurgen,

    You will probably observe reduced sensitivity.

    Regards,
    Yibo