Capability of EVAL-AD7147

Question

I'm new to analog circuits so forgive me if this is a simple question. I'm interested in using a EVAL-AD7147 to measure some external capacitors. From what I saw in the data sheet the CIN pins have already been linked to the example capacitors on board. Is it possible to connect them to external capacitors? 
 Thank you for your assistance.

ADIApproved · Accepted Answer

J1 or J2 are only for connecting to the communications lines between the AD7147 and the ADUC841. The AD7147 currently does not have a method to interface your sensors to the onboard AD7147. I would recommend that you use an external custom pcb with an AD7147 and your design of sensor, which you can then connect to the EVAL-AD7147 via J1 or J2, so that the ADUC841 can be used as an interface to the pc. 
 For your system I would recommend this method, as it is not possible to interface these capacitors directly to the EVAL-AD7147 without modifying the board (cutting the existing traces and soldering them), this will not give a good connection or a reliable result.

ADIApproved · Answer

Hi, 
 The EVAL-AD7147 does not have a facility to connect an external capacitive sensor without modifying the board. The there is an option to connect the power and I2C lines from the board to an external device, so in this case you could build up a small AD7147 board with your required sensors, and connect through J1 or J2 to the EVAL-AD7147's ADUC841 microprocessor. You will need to set the switch on LK1 to OFF, to disconnect the on board AD7147 from the system. When you connect this way, you will be able to carry out your evaluation of the AD7147 on your board using the EVAL-AD7147 board's microprocessor and the supplied evaluation software. 
 Can you share what your application is? 
 Regards, Darragh

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Capability of EVAL-AD7147