[sdiy] Muxes at maximum voltage.

[harrybissell]

Hi Karl... inline

Karl Dalen wrote:

> Hi!
>
> Im about to use a 4051 at +/- 7,5V and logic
> to set mux channel driven from +6V, the specs
> dont tell if 0 to +6V logic are enough for
> logic (ViH) to drive the mux switch!
> Anyone with this experience?

Should be OK.

> Im about to avoid using logic level translators
> such as an transistor array, eg ULN2808 etc.
> Im trying to squeese out as much bipolar
> dynamic range out of old CMOS muxes!

If you really want to squeeze the 4051... locate it at the
summing node of an inverting opamp. Put the input resistors
on the other side. Run it on maybe +15 and run the ground at
-.7V.  Voltage drop across the analog switches will be near
zero... linearity is very good that way.

H^) harry

>
>
> Thanks!
> KD
>
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