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TXB0102: SIM card buffer

Fred Cheng
Expert 5970 points

Part Number: TXB0102
Other Parts Discussed in Thread: SN74AVC2T245, TXS4555, TCA9617B

Hi team,

would you help check if TXB0102 can support below CLK and DATA from SIM card?

I also see someone mentioned SN74AVC2T245 in the forum, which one is more suitable?

  • 0
    TI__Guru 56671 points

    Hey Fred,

    The TXB won't be the best option here for SIM card signals requiring voltage translation since the data ch. is commonly open drain. You can see our list of ASIC translators supporting SIM card applications instead: www.ti.com/.../products.html

    Translate Voltages for a SIM Card

    Regards,

    Jack

  • 0 in reply to Jack Guan
    Prodigy 30 points

    Hi Jack,

    If I would like to use TXB0102 as pure buffer (not level translator) for SIM Card, did you think TXB0102 could be suitable option?

    Or you still recommend TXS4555 is more suitable ?

  • 0 in reply to Kaler Chen
    TI__Guru 56671 points

    Hi Kaler,

    There isn't any buffering circuitry in the TXB0102/ TXS4555 that will help redrive the SIM data signals. For instance, the output drivers of the TXB0102 are intentionally designed to be weak (~4kohms equivalent) to support the auto-bidirectional functionality (in any case, TXB devices should not be used with open-drain signals). 

    What is the trace/ cable length the customer system requires? 

    Regards,

    Jack

  • 0 in reply to Jack Guan
    Prodigy 30 points

    Hi Jack,

    Thanks for you feedback.

    The length we encountered is above 20cm, but length module's guide preferred is within 10cm.

    Is there any recommendation for redriving of SIM data/clock?

  • 0 in reply to Kaler Chen
    TI__Guru 56671 points

    Hi Kaler,

    We do not have any auto-directional buffers to redrive SIM signals at the moment. The only buffers we have are fixed direction/ direction controlled translators and the I2C buffers at the moment. What is the data rate of your data signals? 

    Regards,

    Jack 

  • 0 in reply to Jack Guan
    Prodigy 30 points

    Hi Jack,

    Thanks for your feedback.

    What I can survey for data rate is 1Mbps.

  • 0 in reply to Kaler Chen
    TI__Guru 56671 points

    Hi Kaler,

    1Mbps is equivalent to about 500KHz. In that case, there is the TCA9617B (2 ch I2C buffer) that can be used to redrive the open-drain data signals. As for the fixed direction signals (RST and CLK, a 2-bit fixed direction/ direction controlled translator such as the SN74AVC2T245 can be used). 

    It is important to note that the TCA9617B has a heightened VOL level (about .52V) on B-side. Please ensure that the downstream device can support this as valid VIL. Similarly, the VOL of the downstream device should also be capable of driving below the VIL requirement on the TCA9617B's B side (also known as VILC). This is discussed further in section 6.1 of the datasheet.

    Regards,

    Jack