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TCA4311A: Question about TCA4311 usage

Kazuhiko Hirano
Genius 16198 points

Part Number: TCA4311A
Other Parts Discussed in Thread: TCA9511A, TCA9617B

Hello,

At my customer, a host uC is on the board #1, a slave device is on the board #2 and they are connected each other via a connector. In case VCC1 gets ON first while VCC2 is OFF(0V), they observe some voltage on the slave device I2C bus through the pull-up resister on the board #1.
#A.png

To avoid this uncertain voltage on the slave device I2C bus, they plan to put a TCA4311A as follows. Does TI think this works as they plan?
#B.png

Best regards,

K.Hirano   

  • 0
    TI__Genius 16198 points

    Hello,

    Let me correct their plan as follows. There are no pull-up resisters on the board #2.


    Best regards,

    K.Hirano

  • 0
    TI__Guru 61278 points

    Hi K.Hirano,

    I would recommend TCA9511A over the TCA4311A. The 4311A device has a missing ACK errata. 

    A TCA9511A buffer would work well here by separating the two boards #1 and #2. The buffer would connect board #1 to board #2 only when both VCC1 and VCC2 are powered up. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Genius 16198 points

    Tyler,

    Thank you for your response.
    However, my customer wants to use parts that have already been used and registered.
    Unfortunately, TCA9511A has not been registered so far.
    Please find the attached TCAxxxx parts list for already registered at the customer.
    Are any of these can be used as alternative of TCA9511A?
    TCA device list.xlsx

    Best regards,

    K.Hirano

  • 0 in reply to Kazuhiko Hirano
    TI__Guru 61278 points

    Hi K.Kirano,

    My recommendation is to work to register the TCA9511A rather than TCA4311A. There is no p2p option to replace the TCA4311A with the current list given. 

    For similar functionality, I would use the TCA9617BDGKR as the buffer with A-side facing the Host uC and the B-side facing the Slave device. Then ensure that the buffer is disabled by its EN pin (held LOW) while the board #2 is being plugged in. Once both sides are idle, enable the TCA9617B buffer. 

    Also, you would need to ensure the VIL of the slave device are compatible with the VOLB = 0.58V of the TCA9617B buffer.

    Regards,

    Tyler