HI
Does Cio (on) max (for 3.3V Vcc) of 19pF max apply to both port A and port B.
Finbarr
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HI
Does Cio (on) max (for 3.3V Vcc) of 19pF max apply to both port A and port B.
Finbarr
Hi Finbarr,
Cio (on) comes from both the source and drain capacitance. That means that whichever B port pin is selected would be your source, and the A pin would be your drain. Therefore it is a combination of the two pins.
Please check these slides for more explanation on Cio to help eliminate any confusion.
Finbarr,
Lets attack this question from an IC level perspective. I am attaching an image from the linked PDF to help clarify.
When you use this device there are 3 separate capacitance values we will refer to. C io(off) A port, Cio(off) B port, and Cio(on). Lets look at what each value would be for this device (if conditions are met under electrical spec table).
Cio(off) - Port B (input side of multiplexer) when this channel is not selected - each unselected B port pin would have a typical value of 3.5pF.
Cio(off) - Port A (COM side of multiplexer) - when no channel is selected - A port pin would have a typical value of 19.5pF.
Cio(on) - Port A and Port B (of selected switch) - would have a typical value of 15pF. Meaning a rough model of the signal path of the selected channel would be a 3ohm resistor followed by a 15pF capacitor to GND.
I hope this helps!