SV: Re: [sdiy] 4053 triple SPDT for VCO

[Karl Ekdahl]

I've used both the 4053, 4051 and 4066 for audio and
cv switching. My experience is that the 4053 can
switch more than the VDD - VEE = 15V specified but
above that there will be enormous crosstalk to the
other switches. If i remember correctly, the 4066
simply can't switch higher and i've also blown a
couple of 4051's while switching too high an amplitude
audio. I don't have all my data in front of me right
now so maybe there's some confusion :)

Karl

--- René Schmitz <uzs159 at uni-bonn.de> skrev:

> Hi Aaron, Chad and all,
> 
> > Really? Harry's post got me worried...
> 
> Really. I had a 4053 with this configuration on the
> breadboard not too 
> long ago. The switching was straight to the rails
> between 0 and 15V. I 
> was worried about shorting too, but the circuit
> didn't care about that, 
> and worked. :-)
> 
> (I was testing if I could use a switch without an
> extra comparator as a 
> schmitt-trigger, which would have been handy, since
> one could use the 
> other switches for discharge, turned out the
> switching threshold does 
> drift too much for that, but here the 319 should
> remedy that.)
> 
> I have been haunted by the make break behaviour and
> the intermediate 
> switching to GND also. Yes, Harry is absolutely
> right, and a little 
> caution is in order, you will get unexpected effects
> if you use CMOS 
> switches "naively". (Actually that goes for almost
> every other component 
> as well.) Sometimes you get away by changeing the
> circuit somewhat, and 
> knowing what really goes on inside the ICs and
> discretes does help you 
> then. (IMO the biggest mistake is to see them as
> "black boxes", they are 
> not.)
> 
> This configuration was not meant as a cooking recipe
> anyway, I expect to 
>   see alterations of it, because I haven't tested
> it.
> Also I didn't say you have to use the supplies, but
> that it will work, 
> somewhere below that will of course also work.
> (Might be better, might 
> be worse.)
> 
> Btw. if these auxiliary supplies are current limited
> (opamps can supply 
> ~20mA, a pseudo zehner bandgap will have a limit
> because of the pullup 
> resistor, and so on, so this is very likely that you
> have this 
> unconsciously done already), then this should put
> worries about shorting 
> current aside.
> 
> Cheers,
>   René
> 
> -- 
> uzs159 at uni-bonn.de
> http://www.uni-bonn.de/~uzs159
> 
> 
>