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SN74CBT16209A: Multiplexing two 16 bit data to one 16 bit bus

rajesh beesetty
Expert 1335 points
Part Number: SN74CBT16209A
Other Parts Discussed in Thread: ADS8688, SN74CBT16232

Hello All,

I have an application to read two 16 bit Bus (ADS8688 data). But I don't have sufficient GPIO pins to read the Bus.

So, I am looking for a multiplexer to multiplex the data. Could you please suggest or guide me to select an IC.

  • 0
    Guru 317370 points

    There are 16-channel SPDT switches like the SN74CBT16232.

  • 0
    TI__Guru 52462 points

    Hi Rajesh,

    To clarify, are you using the ADS8688 to read the two seperater bus's? 

    If that is the case, what is the voltage ranges you are looking at for the bus, as well as supply rails that you could provide to the mux?

    Also you highlighted a crosspoint switch; are you reading from one bus at a time or are you reading part of both bus's at the same time?

    Please if you can let me know this information I will be able to pin down the best part for your application.

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Expert 1335 points

    Hello Parker,

    For your question rergarding seperate busses, I don't have sufficient pins to connect to 2nd ADS8688.

    I have two ADS8688 that to be read by C2000 microcontroller. As all the pins are reserved for other peripherals I am not able to connect the second ADS8688 data bus. Could you suggest me how to interface. I have some 10 pins remaining after connecting to 1st ADS8688. These 10 pins I can use for control the 2nd ADS8688 But for the 16 bit bus of 2nd ADS8688, no pins are left.

  • 0 in reply to rajesh beesetty
    TI__Guru 52462 points

    Hi Rajesh,

    Yes, using a multiplexer would most likely be the best approach to expand the functionality of the limited GPIO.

    We have the three options that Clemens linked to above in the thread. 

    SN74CBT16232 

    SN74CBT16233

    SN74CBT16390

    The issue with the above parts is that they are from our CBT line of parts. With a 5V source, you will be able to pass ~3.6V because they are NMOS switches and have an inherent dropout associated with them. If you can provide a 5V source and you aren't trying to measure rail-to-rail voltages these switches would work fine.

    If this is not acceptable, we would have to move to a multi-IC solution to support the large amount of channels you require for your applcation.

    Please let me know if this is acceptable, or if you are open to a multi-chip solution.

    Best,

    Parker Dodson