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TCA9548A: TCA9548A SDAx/SCLx input/output spec

leo shan
Prodigy 30 points
Part Number: TCA9548A

Tool/software:

Hi Teams

My application shows on the picture below.

Q1: what is VIL/VIH parameter on SDx/SCx side?

Since table 5.3 just shows the SDA/SCL(host side) sepc.

Q2: what is the VOL spec on SCx/SDx side?

Fig 5 shows the relationship between VOL and Iol.

I want to know if SDx can refrence this spec or not.

If we can't use fig 5, what is the spec on SDx?

  • 0
    Guru 317170 points

    For high signals, the output voltage is determined by the pull-up resistor. For low signals, the TCA9548A works as an analog switch, i.e., there are no limits, and the output voltage is the input voltage plus the voltage drop shown in figure 5-1. The switch behaves like a 25 Ω resistor.

  • 0 in reply to Clemens Ladisch
    Prodigy 30 points

    Thanks your reply.

    About analog switch, is it limitation on the VCC (Figure 8-2)?
    From our architecture, it is 3.3V to 3.3V, so host vol is 0.4V that can meet 9617 input requesment. Right?

    when we change device to 1.8V, does it means we need to reduce VCC voltage under 3V (ex: 2.7V-1.8V) ?

  • 0 in reply to leo shan
    Guru 317170 points

    Yes; the voltage drop over the switch will be less than 0.1 V, so the 9617 will accept this.

    The pull-up voltages should not be lower than the TCA9548A's supply voltage. With 1.8 V devices, the supply should be 1.8 V.