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TS3L501E: A,B,C,LED pins for TS3L501E

yoshiki hasebe
Mastermind 6385 points
Part Number: TS3L501E
Other Parts Discussed in Thread: TS5MP645

Dear Sirs,

My customer asked us about A,B,C,LED pins for TS3L501E.

Is there a problem if the voltage is applied to A,B,C,LED pins  when VDD=0V？

The customer is thinking if this device is applied to each of the above pins in PowerOFF state (ex. The cable is connected from the outside etc.).

 

Best Regards,

Y.Hasebe

 

  • 0
    TI__Mastermind 45350 points

    Yoshiki-san,

    Placing a voltage on the A,B,C,LED pins with VDD=0V is outside the recommended operating conditions of the device.  

    There are devices that define the switch state when VDD= 0V like the TS5MP645 which ensures Hi-Z state when VDD= 0V.  You can filter on the feature powered off protection to find these types of devices on Ti.com.  

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    Mastermind 6385 points

    Hello Adam-san,

    Thank you for your reply.

    I have one more question.

    In the LAN SWITCH products, I think that there is no Power Off Protection function only for LED support products.
    Do you know why there is no Power OFF Protection function?

    Please let me know about this question.

    Best Regards,

    Y.Hasebe

  • 0 in reply to yoshiki hasebe
    TI__Mastermind 45350 points
    Yoshiki-san,

    Are you talking about the TS3LXXXX products or other products in the market? The TS3LXXXX devices do not have the powered-off protection feature because the design architecture of the switch didn't include it. There is some extra cost associated with this feature and at the time of designing this product it was decided that the market didn't demand such a feature.

    We are seeing increasing demand for this powered off protection feature and are including it in newer devices such as the TS5MP645 device.

    Thank you,
    Adam
  • 0 in reply to Adam Torma
    Mastermind 6385 points

    Hello Adam-san,

    Thank you for your reply.

    Yes, I'm talking about  TS3LXXXX products.

    Because my customer uses what supports LED function.

    So I thought that the device that supports the LED function needs to light the LED even when the LAN connector is not connected so that the Power Off function is not installed.
    Is this correct?

    Best Regards,

    Y.Hasebe

  • 0 in reply to yoshiki hasebe
    Mastermind 6385 points

    Hello Adam-san,

    I'm sorry for additional one more question.

    The absolute rating is described as 7V.
    So it seems that there is no Diode between VI/O - VDD.
    However, in Recommended Operating Conditions, it is described as VDDmax.

    In fact, is the Diode between VI/O - VDD included, is not it?

    Best Regards,

    Y.Hasebe

  • 0 in reply to yoshiki hasebe
    TI__Mastermind 45350 points

    Y. Hasebe,

    The absolute max rating states Vio max as 7 V and doesn't reference to the VDD rail because there is not a diode present to VDD.

    The recommended operating conditions states the Vio voltage max as VDD because this device performance is not guaranteed if the I/O signal is above supply voltage.

    What is the concern with the diode to VDD in your system?  What would you have to do different in your system if there we an esd diode from I/O to VDD?

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    Mastermind 6385 points
    Hello Adam-san,

    Thank you for your reply.

    I understand that I do not refer to the VDD rail because there is no diode in VDD.
    My customers worry about whether the device will be destroyed when a signal is input to Vi / o at VDD = 0V.
    So I asked questions about Diode.
    From your answer above, it is thought that even if you input a signal at VDD = 0 V, it will not be destroyed because there is no path through which current flows.
    Is this correct?

    Best Regards,
    Y.Hasebe
  • 0 in reply to Adam Torma
    Mastermind 6385 points
    Hello Adam-san,

    Thank you for your reply.

    I understand that I do not refer to the VDD rail because there is no diode in VDD.
    My customers worry about whether the device will be destroyed when a signal is input to Vi / o at VDD = 0V.
    So I asked questions about Diode.
    From your answer above, it is thought that even if you input a signal at VDD = 0 V, it will not be destroyed because there is no path through which current flows.
    Is this correct?

    Best Regards,
    Y.Hasebe
  • 0 in reply to yoshiki hasebe
    Mastermind 6385 points
    Hello Adam-san,

    I forgot one more question.
    When the I / O signal exceeds the power supply voltage,
    What are you thinking about symptoms that can not guarantee performance?

    Best Regards,
    Y.Hasebe
  • 0 in reply to yoshiki hasebe
    TI__Mastermind 45350 points

    Y. Hasebe,

    TI cannot guarantee operating the device outside the recommended operating conditions which states voltages on the I/O may only be as high as VDD.  The abs max rating states signals on I/O path may be as high as 7V but exceeding this rating may cause permeant damage to the device. 

    Thank you,

    Adam