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Two AD5933 on the same I2C bus

Hello there,

I am currently working on biomedical project which use a single chip impedance analyzer (AD5933) and so far it's working for the intended purpose. My question is how can I use two AD5933 on the same I2C bus. The problem is both of them have the same address, hence it hard to access them separately. 

Trying to use a multiplexer, like Adafruit TCA9548A multiplexer. But not working. I tried to scan it but not detected. Just bought ADG 728 but it's a chip, I need to prepare a pcb board for it. No way to check it ahead if it is working or not .

What shall I do ? is there anybody who works on this type of project ? Thanks in advance.



Parents Reply
  • You need to use two ADG728 chips. With those you can connect up to 8 AD5933, If only up to four AD5933 would suffice it is better to use one ADG729 chip (you indicated you need only two AD5933). Here is how to wire the ADG729:

    You can connect any of the SCLi and SDAi to one AD5933 and any SCLj and ADAj, where i ≠ j to the second one. Of course attach VDD and GND to you circuit power and ground and connect A0 and A1 to select some available address for the ADG729 on your I2C bus. Good idea to use pull-up resistors on all I2C lines connected to the AD5933 chips. Then just write whatever codes required into the ADG729 to route I2C signals to the one of the AD5933 you intend to work with at a given time (ADG729 is a switch array, so it is worth making sure that only appropriate switches are ON).

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