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SD card hot swapping solution

Daisuke Maeda
Guru 19845 points
Other Parts Discussed in Thread: TXS0206, TXS02612

Can voltage level translation devices for SD card be used for hot swapping?

Can you provide a recommended solution?

In current board design of our customer, SD card can be powered off but the data/command pins can be driven by host device during power off.

Best regards,

Daisuke

 

  • 0
    TI__Expert 6430 points

    Hi,

    I will check this feature with designer and let you the feedback.

    Thanks

  • 0 in reply to Wei Lang
    TI__Expert 6430 points

    Hi

    TI translation for SD card does not have hot swapping feature.

    In your case, TXS0206 can be used. TXS0206 can be disable by set EN pin to low. Then all I/O will be pull-up by internal 40k resister.

    Thanks

  • 0 in reply to Wei Lang
    Guru 19845 points

    Hi Wei,

    Thank you for your reply.

    In the customer case, B side of the translation is powered off when SD card is powered off. For the hot swapping feature, is it allowed that only B side (VCCB) is powered off?

    The customer may use TXS02612. Can it be used for the hot swapping feature?

    Best regards,

    Daisuke

     

  • 0 in reply to Wei Lang
    Guru 19845 points

    Hi Wei,

    Daisuke Maeda said:

    In the customer case, B side of the translation is powered off when SD card is powered off. For the hot swapping feature, is it allowed that only B side (VCCB) is powered off?

    The customer may use TXS02612. Can it be used for the hot swapping feature?

    I worry whether a leakage current from A (host controller) side gives damage to SD card while only B side (VCCB) is powered off.

    Please give me an answer as soon as possible. Your prompt reply would be appreciated.

    Best regards,

    Daisuke

     

  • 0 in reply to Daisuke Maeda
    TI__Expert 6430 points

    Hi,

    For TXS02612, if VCCB is power off and VCCA is power on, A side I/O will be at high-impedance. To make sure the device can work under hot swapping condition, it is better to power off  B side powr supply.

    Thanks

  • 0 in reply to Wei Lang
    Guru 19845 points

    Hi Wei,

    Thank you for your reply.

    Wei Lang said:

    For TXS02612, if VCCB is power off and VCCA is power on, A side I/O will be at high-impedance. To make sure the device can work under hot swapping condition, it is better to power off  B side powr supply.

    For TXS0206, is this same?

    Best regards,

    Daisuke

     

  • 0 in reply to Wei Lang
    Guru 19845 points

    Hi Wei,

    For TXS0206, if VCCB is power off and VCCA is power on, are the outputs of B (SD Card) side placed in Hi-Z state? Should EN pin be pulled low?

    For TXS02612, if VCCB is power off and VCCA is power on, are the outputs of both B0 port and B1 port placed in Hi-Z state? Are the outputs which are selected by SEL pin placed in no Hi-Z state?
     
    Please give me an answer as soon as possible. Your prompt reply would be appreciated.

    Best regards,
     
    Daisuke

     

  • 0 in reply to Daisuke Maeda
    TI__Expert 6430 points

    Hi,

    For TXS02612, if VCCB is power off and VCCA is on, there  there is about 15k resistor between I/O and VCCB.

    For TXS0206, if VCCB is power off (VCCB should be 0V)and VCCA is power on, there is about 30k resistor between I/O and ground whatever EN is high or low.

    Thanks

  • 0 in reply to Wei Lang
    Guru 19845 points

    Hi Wei,

    Thank you for your reply.

    Best regards,

    Daisuke