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TS5A21366: Low output capacitance switch

Gabriele Clapier
Intellectual 1280 points
Part Number: TS5A21366
Other Parts Discussed in Thread: TS3USB31E, TS5A9411, SN74CBT3306, TS5A623157, SN74CBT3305C, TS5A63157

Hi,

  I need an analog switch with very low OFF capacitance on its output (capacitance during off state). 

At the moment I've found the TS5A21366 but its Cno(OFF) = 19pF is too high for my application.

Is there any part (dual of single) with lower Cno(OFF) ?

Kind regards

Gabriele

  • 0
    TI__Expert 3180 points

    Hello Gabriele Clapier,

    Fortunately we do offer many switches that have a 2 Ch. configuration for 1:1 SPST.

    Unfortunately, we have a lot to choose from.

    You can find these at:

    Besides output capacitance in the Off state, is there any other spec that you customer would like?

    I noticed the device you chose has exceptionally low Ron as well as a wide Vcc range, does the other switch have to be identical here as well?

    Or is there a range for either that they are trying to meet?

    Could you share what your customer might be using this switch for?

    These answers will allow us to properly assist you and your customer.

    Thanks,

    Louie

  • 0
    TI__Mastermind 45475 points

    Gabriele,

    Here are the results for my search for 1 or 2 channel 1:1 SPST devices that have off capacitance < 19pF I did on TI.com. The results returned 39 different devices that meet your requirements above.  What do you think about TS3USB31E 2pF off-state capacitance?

    To help us narrow down the search further what is reason you need the switch in your application?  Do you know what signals you would like to pass,  voltage swing, bandwidth, etc?  Do you have any package preferences? 

    Let me know what other questions you have.

    Thank you,

    Adam

     

  • 0 in reply to Louie
    TI__Intellectual 1280 points
    Hi,
    very low impedance is not a key parameter thus even some ohms could be fine. Across the switch there is a signal with a bandwidth of about 15MHz.

    Please let me know a switch with low Cno(OFF) .
    Thank you very much for your support
    Kind regards
    Gabriele
  • 0 in reply to Gabriele Clapier
    TI__Expert 3180 points

    Hello Gabriele,

    Please see the image below:

    This is a list comparing 5 switches with the mentioned spec:

    2 Ch.

    1:1 (SPST)

    Bandwidth >> 15MHz

    Low Con (I have circled the one with the lowest Con)

    Since you did not mention a voltage range, I only included devices here which have a similar voltage range(except for the device with lowest Con which has a Vcc from 2.25 to 4.3V)  as the device you mentioned in your question.

    Thanks, 

    Louie

  • 0 in reply to Louie
    TI__Intellectual 1280 points
    Hi,
    thanks for you support.
    We just defined the power supply of the entire signal chain and "unfortunately" it is 5.0V.
    Nevertheless on the datasheet of the TS3USB31E the Vcc Absolute maximum rating is 7V and the "recommended conditions are 4.3V max.

    Can the TS3USB31E work at 5.0V (or better 5.5V) ?
    Do you have any characterization data of the TS3USB31E at 5.0V ?

    As 5V switches with low Cin(OFF) I've found:

    TS5A9411: 10-Ohm SPDT Analog Switch
    SN74CBT3306: Dual FET Bus Switch
    TS5A623157: Dual 10-Ohm SPDT Analog Switch With Undershoot/Overshoot Voltage Protection
    SN74CBT3305C: Dual FET Bus Switch with -2 V Undershoot-Protection
    TS5A63157: 15-Ohm SPDT Analog Switch 5-V/3.3-V Single-Channel 2:1 Multiplexer/Demultiplexer

    What do you suggest taking also into account the "robustness" against overshoot or undershoot on the data line (this switch will isolate the data line from a twisted pair bus)

    Thanks
    Gabriele
  • 0 in reply to Gabriele Clapier
    TI__Expert 3180 points

    Hello Gabriele,

    As for the TS3USB31E, TI would not ever recommend operating the switch above the recommended conditions. You can attempt to operate the switch at 5V, but TI cannot guarantee functionality or how long the device will function properly for.

    As far as the 5 switches you have listed below, if you want to sue the switch for isolating signals, i would suggest looking at the spec Oiso, as this is the off isolation spec. This is how well the switch will block off a signal. Robustness to overshoot or undershoot is actually more related to  

    Another spec I would look at is charge injection, as this can cause slight over or undershoot in a signal. (Qc)

    Thank you,

    Louie