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TMUX7612: Charge injection

Koshi Ninomiya
Expert 5745 points
Part Number: TMUX7612
Other Parts Discussed in Thread: TMUX6219

Dear Team,

My customer is evaluating the TMUX7612PWR. 
They would like to know about the electrical characteristics of Charge injection.
The Charge injection (QINJ) is defined by CL=100pF in case of the TMUX7612 as below.

image.png

However the Charge injection (QINJ) is defined by CL=1nF in other TMUXs.
For example of the TMUX6219 as below.

Is there a reason for this difference in load capacitance?

They would like to know the following points.
1) Is it possible to simply compare Q_INJ with two products specified with Q_INJ by CL=100pF and with CL=1nF?
2) If a simple comparison is not possible, with a low CL test condition, does Q_INJ become higher or lower?
    (In other words, if Q_INJ of the TMUX7612 is specified with CL=1nF, will it become higher or lower than the value in the datasheet? Ideally, they want to know Q_INJ with CL=1nF.)

Best Regards,

Koshi Ninomiya

  • +1
    TI__Mastermind 22495 points

    Hello Koshi,

    Charge injection is measured as below:

    The capacitance load you are referencing are part of the test conditions when measuring charge injection. Different parts use different loads since their charge injection behavior is not the same. 

    1. Not really, since these two devices have some slight differences in internal design where you wouldn't be comparing "apples to apples". 

    2. It will be very similar to almost the same, since the difference between 1nF and 100pF is not that large. 

    Thanks,

    Nir