MAX333A(analog and digital parts)

Thread Starter

Crowbar

Joined Dec 19, 2006
32
Hi. I have a question about MAX333A analog switch: It will be used to switch on-off HPF filters. My circuit have separated analog and digital grounds, connected in a single point(star)- max333a have only one GND pin(no separated agnd dgdg)- how this GND must be connected to analog and digital grounds of my circuit(should i connect only dgnd to MAX333A GND or agnd must be connected also)?

Regards, Konstantin.
 

beenthere

Joined Apr 20, 2004
15,819
Hi,

Looking over the spec sheet, the ground pin is used as a reference for the logic signal, so connect to the digital ground.
 

Thread Starter

Crowbar

Joined Dec 19, 2006
32
Howhever, this anlog switch is using transistors of course- as i remember the simple transistor switch has common emitter which is connected to gnd; to be honest- I am dissapointed looking on MAX333(sorry, where at pdf Have you seen that gnd is used as a digital reference?)

Best Regards.
 

beenthere

Joined Apr 20, 2004
15,819
Hi,

The analog switch uses FET's as switching elements. I've used analog switches before - the logic signal needs the ground. The limits of the switch's signal capability are set by the V+ and V- terminals.
 

Thread Starter

Crowbar

Joined Dec 19, 2006
32
There we have leakage current and on resistance only wich affects noise, i suppose, but no directly noise specs..
 
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