TCA9539-Q1: Output VOL

Hi Clemens,

Got it.

BTW, if I connect Px ports to other converter or ICs control pins, just need to make sure the source current from those pins of the ICs I connected to will not cause huge source current and affect the VOL of TCA9539-Q1, right?

Just in case it might accidentally trigger the VIL of those ICs.

Yes. Those other pins are likely to be CMOS inputs, with leakage currents in the µA range. But adding a pull-up resistor will increase the current.

Hi Clemens,

Since our Px ports are all Push-Pull structure so no extra pull-up resistor will need I think.

Even we connect to other POL's EN pin.

But you're right, if we add other pull-up resistor on those pins then extra sink current will happen.

Evan Wang said:

I notice below figure shows the VOL variation based on sink current, I believe it assume that there is another source on the line and sink into the Px port then cause the VOL.

Is my understanding correct?

VoL of the p-port is a function of V=R*I where V is VoL, R is the Ron of the NFET of our device, and 'I' is the current that the NFET is sinking. If you know what the current or load external to the p-port is, you can calculate the VoL. 

-Bobby