I would like to isolate two 3.3V domains, circuit_X connected to circuit_y.
When the switch is off it should insulate from backfeeding from circuit_X domain to the circuit_y domain.
I.e. here i would like to use an analog switch and need 6 channels.
What do you think about the CD74HCT4066-Q1 for this?
Hi,
Thank you for your question.
This is a feature we call "Powered-off protection". This means that when the switch is turned off (supply voltage = 0), both the inputs and the outputs go to high impedance. This will help prevent the backfeeding that you describe.
To find devices with this feature, we have a One-Click Parameter option at the top of our Parametric Search Table. This can be found at 
, then clicking on "Analog Switches and Multiplexers" and clicking on the "Products" tab.
You can further filter by configuration, channel count, and Vdd (positive power supply) on the side bar as shown below:
Here are the devices that meet your criteria. I would recommend a combination of two devices such as:
SN74CB3Q3125 (4 Channel, Ron = 4 Ohm typ) and SN74CB3Q3306A (2 Channel, Ron = 4 Ohm typ)
because they have similar typical on-state resistance.
Please let us know if you have any further questions.
