This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Regarding the setup of TCA9546(with PCA9306 series model) in the simulation

Other Parts Discussed in Thread: PCA9306, TCA9546A

Hi Support

Thanks a lot for all feedback in the past.

I have a couple of questions about the simulation setup.

In our system, we have two TCA9546, the first one (next to Master) will transform the voltage level, and the second one(next to Slave) will keep the voltage level.

Firstly, it looks to me like the pass-FET model of PCA9306 will implement voltage transform after I did some simulation.

So, for the data write(from Master to Slave), the first TCA9546 should use PCA9306_IO_33_S, which can change the voltage from some voltage(it might be 1.8/2.5/5V, and now we use 1.8V) to 3.3V, correct?

For the data read(from Slave to Master), since it 1.8V application for Master, I chose the PCA9306_IO_18_S voltage transform model to transform the voltage to 1.8V, correct?

Please help check my setting below is correct or not.

  • Hi Klaus,

    Are you running an IBIS model simulation? 

    I believe both of your write and read simulations should be using the bottom illustration (the read one). The TCA9546 technically would not operate correctly (would not support 3.3V Vcc and provide level shifting down to 1.8V), you would need 1.8V on Vcc to support up to 3.3V not the other way around. The 1.8V model would also give you the 'worse' case in terms of the series model. 

    Does this answer your question?

    Thanks,

    -Bobby

  • Hi Bobby

    Yes, I'm running the simulation with this IBIS model modified by me in the HyperLynx.

    Looks like we should check what's VCC we use in the design, and we can choose the corresponding model.

    Then,

    On board 1, the VCC is 1.8V, we should use 1.8V IO open drain and use PCA9306_IO_18_S for data write and data read.

    On board 2, the VCC is 3.3V, we should use 3.3V IO open drain and use PCA9306_IO_33_S for data write and data read.

    Is it correct?

    Regards,

    Klaus

  • Hi Klaus,

    That is correct. 

    I'm guessing you are using the PCA9306 model because we don't have a series model available right now for the TCA9546A. This is probably the best substitute currently until we update the TCA9546A IBIS model to include series models.

    -Bobby