[sdiy] CMOS Mux Question

[harrybissell]

You could tie them down (or up) but if you accidently turned them
ON you might get high current from the input pin.

Why not tie them migh, or low, through a pull down (up) resistor ???

(strictly speaking, I don't think you need to tie them at all...)

What does the data sheet / app notes say ???

H^) harry

Seb Francis wrote:

> Hi,
>
> I've just built a MIDI2CV converter for my Oakley 3031.  It's using the
> same PCB I used for my 15xCV modular converter, but since I don't need
> this many CVs I'm only fitting the required number of S&H caps and
> output buffers.  This means that I have the unused outputs from the CMOS
> Mux left not connected to anything.
>
> The Mux in question is the MAX306.  It doesn't say anywhere in the
> datasheet that you have to connect every input/output, but I remember
> that this is generally a good thing to do with CMOS ICs.  Does anyone
> have any advice on the matter?
>
> Will it have any bad effect just to leave the unused outputs not
> connected?  The uProc software will never switch the input to them.
>
> Here's the datasheet for the MAX306..
> http://pdfserv.maxim-ic.com/en/ds/MAX306-MAX307.pdf
>
> Seb