[sdiy] Muxes at maximum voltage.

[Tim Parkhurst]

How about using two 4051s in series to increase the voltage range? I know it
sounds goofy, but I'm just wondering if it might work. Basically, you run
each 4051 off of +/-7.5V. Now, each analog switch looks like a low-value
resistor (about 80 - 100Ohms), and if you put two resistors in series each
one drops half the voltage. In theory, you could stuff a +/-10V signal in
and each 4051 would only see +/-5V. This seems too simple, so I'm wondering
if there is some fundamental flaw that I'm missing. At first I thought you
would want to run the 4051s in parallel, but then they each take half the
current (and the voltage remains the same). Any comments or abuse from the
EE heavyweights out there?



Tim (EE flyweight) Servo
"Imagination is more important than knowledge." - Albert Einstein




> -----Original Message-----
> From: Karl Dalen [mailto:karldalen at yahoo.se]
> Sent: Thursday, March 18, 2004 8:41 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Muxes at maximum voltage.
> 
> 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?
> 
> 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!
> 
> Thanks!
> KD
> 
> Höstrusk och grå moln - köp en resa till solen på Yahoo! Resor på adressen
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