Good day, group!
My friend has this rough drawing of two analog switch configuration:
I say that the two SPST configuration would be better suited since it would provide better isolation than the SPDT configuration. She says otherwise. Am I wrong?
I also told her that another switch would be required at the output of DeviceA so its output will be isolated from the other signal path. She thinks it's okay. Is there truth to her claim?
Thanks!
It depends on the details of the switches. If you use to SPST switches in two packages, your are likely to get better isolation.
This depends on what exactly DeviceA is. The switch on the output side may be all that is needed in some cases.
Thanks, MooseFET!
I was assuming that DeviceA was just an opamp configuration. However, if it is an opamp with some kind of feedback configuration, then the signal from the other path would be fedback, right? I think she needs some sort of opamp with a shutdown feature or something. That way it can be disabled when the other signal path is used.
This depends on what exactly DeviceA is. The switch on the output side
Since the circuit connects the two switches together, isolation is going to be a function of the switches' OFF resistance, rather than crosstalk between the two switches, so there's nothing to choose between the two configurations.
No, you're right, you need to disconnect the output of device A when connecting 'Signal in' to Signal out', otherwise you will end up with two outputs trying to drive one another. (I'm assuming that 'Signal in' is low impedance and comes from some type of amplifier and that Device A is itself some form of amplifier.
A simpler arrangement would be to connect 'Signal in' permanently to the input of Device A and use the switch, (either arrangement shown in the link), to select between the signals on Device A's input and output.
-- T If it\'s not broken, don\'t fix it.
the puropse of these switches is unclear, both look equally bad. you may need to disconnect the output of "device a".
Bye. Jasen
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.