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TMUX6119: Whether voltage divider input affect the frequency response of passive Low pass filter connect at TMUX6119 ouput side

Lakshmanan V
Intellectual 480 points
Part Number: TMUX6119
Other Parts Discussed in Thread: OPA192, TS12A12511

Dear All,

I am going to design one 8 Channel Data Aquistion Project.

The input details are given below:

1. Each Channel analog input with selectable range ( ± 5V or ±10V ) of Single Ended input.

2. Input Impedence 1M Ohm

3. Input is DC Coupling.


Here is My block diagram is attached below.

Here Op-Amp OPA192 is used for Buffering the Input . The output of OPA192 is directly Connected to one input of TMUX6119
and Divider output of OPA192  is connected with Another Input of TMUX6119. Through MUX ic we are selecting ± 5V input from OPA192 or ±10V input from voltage divider.

The TMUX6119 selection is Controledl by MicroController / FPGA.

Due to Transmission Gate( TMUX6119 ) Whether voltage divider reistor input will affect the passive low pass filter response?

Please give your suggestion .

Regards

Lakshmanan V

  • 0
    TI__Expert 3820 points

    Hi Lakshmanan,

    The internal resistance and capacitance of the TMUX6119 can be considered as a RC-Filter with Ron and Con. 
    If Ron is too high you might want to consider the TS12A12511 which has an Ron of 5 Ohm (in comparison to 120 Ohm).

    How many bits does your ADC have? Any Mux will add some leakage current, factor this in into your choice.

    To optimize your filter in front of the ADC I recommend you our application note on that subject: 

    Let us know if you have more questions.

    Best regards,

    Ambroise