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TMUX6112: TMUX6112

Vishnu Jayaraj
Prodigy 170 points
Part Number: TMUX6112

Hi,

We are using analog switch part number TMUX6112PWR for differential input measurement. The Switch is used to complete a resistive path and the voltage drop across the resistor is to be measured ( Diagram 1).

The Switch is biased in single supply mode.

The signal source is isolated from PCBA ground and power. The requirement is we need to invert polarity of signal source and get the value across the resistor (Diagram 2).

In the data sheet of TMUX6112PWR, it states that Source pins and Drain pins can be used as input or output. 

The signal source maximum range is +-3V@22mA.

Currently we are able to measure both positive and negative values by changing the polarity of signal source even if analog switch is biased only in single supply mode.

We believe for our application (as shown in diagram 1,2) negative supply voltage is not required for TMUX6112PWR. Could you please confirm.

Regards

Vishnu

  • 0
    TI__Genius 13980 points

    Hello Vishu,

    Theoretically this  should work however the safest thing to do would be to connect vss to -15v.

     The reason why is if the system is noisy, because the input the diff amp is hi z  If noise in  injected  onto the line   the   common mode voltage  of those two lines could shift the lines negative and if that happens then it could cause issue because you are trying to operate mux below vss=GND=0V.

    Again this could work but there is risk because common mode on the lines hi z.