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TCA9545A: TCA9545A

SAMY MM
Prodigy 10 points
Part Number: TCA9545A


Hi ,

I planning to use I2C, TCA9545A switch, to calculate pull up resistance value for slave do i need to sum the trace capacitance for both the lines SCL and SDA?

for example SCL signal has trace capacitance - 25pF, SDA has - 25pF, as i have 4 slaves the should i consider  bus capacitance as 200pF or 100pF?

Thanks

  • 0
    TI__Guru 62920 points
    Hi Samy,

    You wouldn't add SDA and SCL capacitances together, since they are independent lines each with their own pull-up. You would add up the capacitances on either side of the switch, though. For example, the master node's SDA line would be loaded not just by it's own parasitic capacitance but also by the capacitances of any slave nodes whose channels are switched on. Please let me know if this isn't clear or if you have any further questions.

    Max