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TXS0102: Multiple slaves devices

Mars Huang1
Prodigy 120 points
Part Number: TXS0102
Other Parts Discussed in Thread: TCA9509

Hi,

    If one master to multiple SLAVES, can I use only one TXS0102? Or do I need 2pcs TXS0102?

    is there any other Part number can 1 to 2 suggestion? Thank you.

  • 0
    TI__Mastermind 46195 points

    Hey Mars,

    These devices are recommended more for point to point communication. The main reason for this is because it adds a little complexity to the I2C. In a normal scenario, the I2C bus safe from damaging bus contention since its an open drain interface and the pull-ups wouldn't source damaging currents. The TXS device contains internal one-shots to help accelerate edge rates for better SI. These one shots provide a low impedance path to Vcc so if the other device on the bus drives Low for any reason it possible to be damaged. Otherwise, from the device perspective you are just adding a little more capacitive loading due to the extra device Ci.

    We have a wonderful TXS EVM which you can find in the product folder that would help you evaluate this as well.  

  • 0 in reply to Dylan Hubbard
    Prodigy 120 points

    Hi Dylan,

                    So, if the device Ci increases, will the bit rate decrease?

                    Or do I need to use 2 pcs TXS0102? 1 to 1?

                    Also, if VCCA=VCCB can work normally?

                   Do you recommend using TCA9509? So allow 400 pF bus capacitance, thank you.

  • 0 in reply to Mars Huang1
    TI__Mastermind 46195 points

    Hey Mars,

    Your RC gets bigger so this will limit the bit rate. 1 to 1 is ideal and I would recommend, but that's not to say its impossible to get by with just 1. VCCA = VCCB is fine for this device. The TCA9509 is not in my product line so I can't really comment on it, but it does perform what you need from looking at the data sheet. I would recommend grabbing an EVM for the TXS device (can be found in the product folder under the Design/Develp. tab) and trying out this circuit. The EVM is very simple to use so a quick test to find what works best should be feasible.