Hello
i would like to use a digital switch instead of analog switch.
I,actually,use the ADG711 analog switch; could you say me if there is a digital switch for this IC?
What are you trying to do ?
Do you want a pin for pin replacement ?
You know there is the 74HC4051.
There is also the H11F3M
I'm curious; why?
Depends on what you want to switch:
SN7408, 7409, 74138...
That's the first question.
Perhaps just as much to the point, just what do you actually mean by a digital switch, and for what specific purpose? 
I would like to use a digital switch instead of to use ADG711 because i would like to have a switch that can be used only when it is necassary and using electricity only when this component is utilized instead of the analog switch that always use a small part of elecricity.
Ok, so how about a single small signal MOSFET or JFET?
Btw, I do wonder what your very special application is that requires the elimination of the 1nA current consumption of an ADG711...
(I also wonder if you'll ever beat that figure by a significant margin no matter what alternative you consider...)
OK, so that is complete nonsense.
We do not seem to be getting anywhere here. 
I would like to have a digital programmable switch using code to make that. I would use it using software interface.
I would like to decide, by myself, if it must be switch on or off.
Okay.
This doesn't clarify why your presently used ADG711 is insufficient or whether the single MOSFET or JFET I proposed in #7 would be a solution. Neither does it make clear what exactly your low-current requirement entails.
I try to explain my problem better.
I have a component (PCF8574) that allows me to use both input and output pins.
On these pins I would like to put protection diodes.
Obviously, according to the setting (input or output), the direction of the diodes changes.
To do this, I thought of building 2 tracks: one for the input and one for the output that start from the same pin and on each of them I place a protection diode.
Since the 2 tracks will be activated according to the configuration (input or output), I need a programmable component that allows me to switch the signal on one track or the other.
If there is no component that allows me to do this, I could install programmable digital switches on each track.
These switches will be set by software so that the opening of the input track (for example) corresponds to the closing of the output track.
Protection against what?
Don't forget the protection for your added circuit!
We still do not seem to be getting anywhere here. Oh well!
That chip already has 20mA (absolute max) input/output protection (clamping) diodes.
Is that not enough?
Leo..
There's absolutely no conceivable scenario in which any kind of switch is going to actually help in protecting pins along the lines you describe.
If you post a schematic of your circuit I'm sure many of us will be able to point out where you could/should add protective measures and how to implement them. I also guarantee you that in doing so, the ADG711 and any substitute will disappear from the schematic, resolving your original question 
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