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Original question:

TCA9509: Thermal via

TCA9509: TCA9509 Related Questions

Matt Qi
Expert 4510 points

Part Number: TCA9509
Other Parts Discussed in Thread: TCA9803

Hi team,

I have three related questions about our TCA9509:

1. Does TCA9509 owns the drive capability as I2C level shifter?

2. The VOL maximum value is 0.3V, I want to make a confirmation.

3. What's the difference between TCA9509 and TCA9617?

Thanks for your time and effort.

Best Regards,

Matt.

  • 0
    TI__Mastermind 48511 points

    Hey Matt,

    Yes the TCA9509 is both a level translator and an I2C buffer. Due to an internal current sensing mechanism on A-side, the VOL on A side ( VOL = 0.3V max) will be slightly higher than that on B side (VOL = 0.2V max). Note that the heightened VOL is also what is known as the static voltage offset. It is by design, as the internal current source helps detects whether the input or output side is driving low in efforts to prevent bus lock-up. 

    One of the key differences between TCA9509 and TCA9617 is the placement of this internal current source. On the TCA9617, this is on B-side, so the static voltage offset follows B-side as well. Below is a quick comparison table of their similarities and differences:

    You may also see this app note for further information pertaining this device. 

    Regards,

    Jack

  • 0 in reply to Jack Guan
    TI__Expert 4510 points

    Hi Jack,

    Thanks for your detailed reply.

    We have a further question:

    Because the cable we use for I2C signals is 2m long and the link is too long, SI recommends adding an I2C reapter (buffer). After evaluation, it is necessary to add a level 2 reapters (buffers). If TCA9617 is added, the voltage of the simulated rear stage exceeds 0.6V. We have a slave. The VIL requirement is less than 0.5V, so the risk is too high, so now we need to change to a reactor with a lower voltage boost, so it is okay for us to change to TCA9509, right? Or is there any other reapter(buffer) with lower VOL to replace TCA9617?

    Thanks for your time and effort.

    Best Regards,

    Matt.

  • 0 in reply to Matt Qi
    Guru 320660 points

    The TCA9803 has low output voltages on both sides. (But it still has restrictions on how its B side can be connected.)

  • +1 in reply to Matt Qi
    TI__Mastermind 48511 points

    Hi Matt,

    What is the required data rate for this application? Is it 400KHz or 1MHz? If it is 1MHz, then the TCA9617 would be the only viable option. The customer may need to flip A and B side and connect two TCA9617 in series such as: Controller -> B<->A <-> B <-> A -> Target. Since the VOL on A side of the TCA9617 is 0.23V max, it will be able to support the VIL=0.5V requirement of the target. 

    If application data rate is 400KHz, the TCA9509 and the TCA980x can be used, but has limitations to how it can be connected as shown in section 10.1.2.2 of TCA980x datasheet. 

    Regards,

    Jack 

  • 0 in reply to Jack Guan
    TI__Expert 4510 points

    Hi Jack,

    Thanks for your explanation and reply.

    Best Regards,

    Matt.