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TS3A44159: About IN1-2/IN3-4 pin

Tao_2199
Genius 5660 points
Part Number: TS3A44159

Hello,

 

Regarding to IN1-2/IN3-4 pin on TS3A44159, my customer is asking a question.

On thier application., IN1-2/IN3-4 pin are connected to VCC with pullup.

 

(Question)

When Vcc is on,IN1-2/IN3-4 pin are also on at same time.

In this case, is there any impact on this device?

 

Regards,

Tao_2199

  • 0
    TI__Expert 5660 points

    Hello,

    According to the following table from page 19 of the datasheet, IN controls whether COM is connected to NC or NO.

    The logic diagram shows that IN1-2 controls channels 1 and 2, and IN3-4 controls channels 3 and 4. Controls IN1-2 and IN3-4 may be the same or different. If both are on at the same time, all channels will connect COM to NO.

    If you have any additional questions, please let me know.

    Regards,

    Kate

  • 0 in reply to Kate Dickson
    Genius 5660 points

    Hello Kate,

    Thank you for reply.

    In case of IN1-2/IN3-4 pin are connected to VCC with pullup,
    When Vcc and IN1-2/IN3-4 pin are on at same time, COM is switched to NO at same time that Vcc is on.
    According to datasheet(10 Power Supply Recommendations:page22),
    “Always sequence VCC on first, followed by NO, NC, or COM.”

    In above condition(Vcc and IN1-2/IN3-4 pin are on at same time), is there any problem?
    I’m asking that just in case.

    Regards,
    Tao_2199

  • 0 in reply to Tao_2199
    TI__Expert 5660 points

    Hello,

    If you connect IN1-2 and IN3-4 to VCC, this configuration may cause unexpected outputs just during power-up.

    To avoid concerns with power sequencing, it is best to use a switch with powered-off protection. If you would like, I can make a recommendation for a switch with powered-off protection. Please send a block diagram of your system so I can better understand this application.

    Regards,

    Kate

  • 0 in reply to Tao_2199
    TI__Expert 5660 points

    Hello,

    Just checking in that your question was answered. I am marking the case resolved, but please don't hesitate to reach out if you have any more questions!

    Regards,

    Kate

  • 0 in reply to Kate Dickson
    Genius 5660 points

    Hello Kate,

    Sorry for delay.
    I informed to my customer your answer, and they will consider a switch with powered-off protection again.
    I will close this thread.
    Many thanks!

    Regards,
    Tao_2199