ADI filter wizard vs LTspice questions

The stage order will be based on whatever optimization you had before you switched to "I want to choose" to be able to pick the AD8606. 


If optimization was "Voltage Range" the tool will optimize the stage order for input voltage range, which generally means the low Q stages will be first and high Q stages last.  If the optimization was "Low Noise", then the stage order will likely be the opposite, since having high Q stages first normally gives better noise performance.  If the optimization was "Low Power" (the default) then the tool doesn't optimize and just goes with whatever stage order the specifications tab came up with.  In practice I think the specifications tab typically starts with the higher Q stages first (not intentional), so the "Low Power" inherits from there.  If I had to do the tool over again, I agree it would be better to default low Q to high Q for "Low Power" instead.

Note that in "I want to choose" mode you can change the stage order manually. If you hold the left mouse button down, you can move the stage letters to a different position to change the stage positions.

You may want to do this with the Stages view shown, so that you can see the Q's of each stage:

The stage order will be based on whatever optimization you had before you switched to "I want to choose" to be able to pick the AD8606. 


If optimization was "Voltage Range" the tool will optimize the stage order for input voltage range, which generally means the low Q stages will be first and high Q stages last.  If the optimization was "Low Noise", then the stage order will likely be the opposite, since having high Q stages first normally gives better noise performance.  If the optimization was "Low Power" (the default) then the tool doesn't optimize and just goes with whatever stage order the specifications tab came up with.  In practice I think the specifications tab typically starts with the higher Q stages first (not intentional), so the "Low Power" inherits from there.  If I had to do the tool over again, I agree it would be better to default low Q to high Q for "Low Power" instead.

Note that in "I want to choose" mode you can change the stage order manually. If you hold the left mouse button down, you can move the stage letters to a different position to change the stage positions.

You may want to do this with the Stages view shown, so that you can see the Q's of each stage:

Great, thanks for the info on that Matt.  I guess I'd assumed the tool would use the "voltage range" optimization option, as that seems to me, at least, to be the most common use.  

Nice to know that it's flexible, though, thank you.