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TS5A3159: Connect input and Vcc together of TS5A3159

Yarn Guo
Intellectual 1440 points
Part Number: TS5A3159
Other Parts Discussed in Thread: SN74LVC1G3157-Q1

Hi, Team:

May I have two questions regarding TS5A3159-Q1:

-          May I know whether we have the DCK package which is smaller than DBV package. We only see  DBV package for orderable device.

-          TS5A3159-Q1 is used to drive LDMOS PA biasing voltage of 5V. The device is powered up by 5V supply. When PA is on, 5V power supply voltage is routed to the gate of LDMOS PA. When PA is off, the SPDT switch will be switched to ground through resistor.

May I double confirm with you that is it okay to connect NO pin to V+ pin for this application? The PA will draw about max 20mA current from NO pin.

  • 0
    TI__Expert 3180 points

    Hello Yarn,

    Thank you for reaching out to us.

    We currently do not offer the TS5A3159-Q1 1-channel 2:1 SPDT device in a DCK package for this device. Could you list some of the reasons you have for the DCK package?

    However, we do offer the SN74LVC1G3157-Q1 which is also a 1-channel 2:1 SPDT in a DCK package, however it has 15 Ohms of Ron instead of 1 Ohm of Ron(TS5A3159-Q1).

    As far as the application goes, this will work since this device will allow for up to 200mA MAX to pass through NO, NC, and COM pins according to the on-state switch current spec. The datasheet also states that your NO pin is limited by what your V+ pin is, so they are allowed to be equal and may be connected to your 5V LDO, with the assumption your LDO has the proper amount of output current.

    Please see below the two snips from the TS5A3159-Q1 datasheet:

  • 0 in reply to Louie
    TI__Intellectual 1440 points
    Hi, Louie:

    Thank you so much for your detailed explanation.
    Customer wants DCK package for smaller package size. Let me check whether 15Ohm Ron is acceptabel.

    Thank you again for your help

    Yarn.
  • 0 in reply to Yarn Guo
    TI__Intellectual 1440 points

    Hi, Louise:

    Customer is looking for SN74LVC1G3157-Q1 since it has very low price compared to TS5A3159-Q1. Do you have any comments for the difference between SN74LVC1G3157-Q1 and  TS5A3159-Q1. We know the Ron of SN74LVC1G3157-Q1 is larger which is about 15Ohm while customer can accept this.

    But the supporting current of SN74LVC1G3157-Q1  may be the concern. We see on the website that the support current is +/- 32mA as below:

    While, from the datasheet, we see the on-state switch current is +/-128mA, may I know which current value should I trust? If SN74LVC1G3157-Q1  can really support +/-128mA on-state swich current, why the price of SN74LVC1G3157-Q1(1Ku, 0.08$) is quite lower than TS5A3159-Q1(1Ku, 0.34$)?

    It is a little bit urgent. Could you help to look at this today? Thank you!

    Thanks

    Yarn

  • 0 in reply to Yarn Guo
    TI__Expert 3180 points

    Hello Feng,

    The functionality of the switches are more or less identical. The thing you may need to talk to you customers about is what they care about for the use case. For example, their analog switch characteristics are different:

    SN74LVC1G6157-Q1 Datasheet:

    TS5A3159-Q1 Datasheet:

    This is just an example of what you may need to ask your customer specifically to help better choose. These devices also differ in parasitic capacitance, turn on/off time, leakage current, etc. 

    Lastly to address your question about the current this device can handle, the image you posted:

    SN74LVC1G3157-Q1 Datasheet:

    These ratings are absolute maximum values, meaning that if your device were to experience this for a very short time, it could be okay, but for an extended time could lead to permanent damage to the device. A better spec to look at is Ron because it shows the current values they tested up to:

    SN74LVC1G3157-Q1 Datasheet:

     

    Since we know they went up to 30mA in the IO's, this should be a safe number to recommend to the customer. If I recall correctly, 20mA was the MAX you were looking for in the beginning of this post. 

    Hope this answered all of your questions and thank you for reaching out,

    Louie

  • 0 in reply to Louie
    TI__Intellectual 1440 points

    Hi, Louie:

    Thank you for your prompt help.

    May I double check the continuos on current of TS5A3159-Q1 based on your comments:

    - +/-200mA is also the short time maximum current value, not the continuous value based on the datasheet spec and measurment methold as below from TS5A3159-Q1 datashhet?

    -We need to refer to the Ron current for the continuous current supported, which is +/-30mA @ 5V supply?

    Thank you so much for your prompt reply.

    Thanks

    Yarn

  • 0 in reply to Yarn Guo
    TI__Expert 3180 points

    Hello Yarn,

    Actually in the case of the TS5A3159-Q1, you can note that there is the spec you highlighted for ON-state switch current in the absolute ratings, but also the ON-State peak switch current(short time maximum current) right below it. In this case the spec you highlighted is the Maximum ON-State continuous current while the peak is right below. I have attached a larger snippet highlighting the MAX peak and the note under it saying how long its allowed to peak for before damage occurs. I have also circled the MAX continuous on current.

    Please let me know if there are anymore questions.

    Thanks,

    Louie

  • 0 in reply to Louie
    TI__Intellectual 1440 points

    Hi, Louie:

    Fully understand. Thanks for your great and prompt help! Thank you again!

    Best Regards

    Yarn