FDC2214: How can I excite just one custom capacitive sensor with all channels of a FDC2214 sensor?

Pedro Goncalves

Part Number: FDC2214

Hi,

I need connect a custom capacitive sensor to all channels of FDC2214 CI to excite it in 4 different frequencies. How can I do to the other circuits do not get in parallel? Can I use some switch to cut of them whem I using just a channel?

Best Regards

over 6 years ago

0 Jiashow Ho over 6 years ago

TI__Genius 11340 points

Hi Pedro,

Keep in mind that the sensor cannot be connected to more than one channels at the same time. You could consider using a multiplexer to select the the desired channel.

Alternatively, having four identical sensors connected to each channel might be an easier option, if your application allows it.

Best,

Jiashow

0 Pedro Goncalves over 6 years ago in reply to Jiashow Ho

Prodigy 80 points

Hi Jiashow,

Yes, having four identical sensors is one possibility I'm considering using.
But if I using a multiplexer to select the desired channel, It could damage the measured signal by passing it through the multiplexer?

Best,

Pedro

0 Jiashow Ho over 6 years ago in reply to Pedro Goncalves

TI__Genius 11340 points

Hi Pedro,

The mux shouldn't damage the signal. Do make sure that your mux has low series resistance, low capacitance, and high bandwidth (10 times greater than your sensor frequency). This would ensure that your signal isn't diluted.

Best,
Jiashow

0 Pedro Goncalves over 6 years ago in reply to Jiashow Ho

Prodigy 80 points

Hi Jiashow,

It would be ideal for the project to use the same capacitor in different frequencies. Could you tell me some texas multiplexer that has these features? The maximum excitation frequency is 9 Mhz.

Best,

Pedro

0 Jiashow Ho over 6 years ago in reply to Pedro Goncalves

TI__Genius 11340 points

Hi Pedro,

I've filtered the search based on the criteria here, you could browse through these devices and select the one that best fits your application.

Thanks,

Jiashow

0 Pedro Goncalves over 6 years ago in reply to Jiashow Ho

Prodigy 80 points

Hi Jiashow,

Thank you very much for your attention and support.

Thanks,

Pedro

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FDC2214: How can I excite just one custom capacitive sensor with all channels of a FDC2214 sensor?