[sdiy] Another new hard to find part....

[Scott Gravenhorst]

"Roy J. Tellason" <rtellason at blazenet.net> wrote:
>On Tuesday 06 July 2004 12:13 pm, Scott Gravenhorst wrote:
>
>> >> Not only will CD4xxxx work to 15 volts (some parts to 18), they will
>> >> also work down to 3 volts.
>> >
>> >True,  though this isn't an area where I've taken advantage of it yet.
>> >
>> >> I have run several CD4xxxx based circuits from +/- 8 volts without
>> >> problems. I just make sure all of the parts in the design are speced to
>> >> 18 volts.
>> >
>> >What's that,  the "B" series?
>
>> "B" at the end of the number just means "buffered".
>
>No,  I have the original RCA databooks on those parts.  The "A" series was 
>only rated to go to 15 volts,  while the "B" series went to 18 -- but that's 
>an "absolute maximum rating" and you don't usually want to go there,  quite.

Right, but it depends on the part.  The sheet for 4007 says 3 to 18 volts, but
calls it a 20 volt part.  ??  Anyway, I've used these 18 volt parts that also
spec to max 15 volt power at 16 volts (+/- 8 volts) and I've had no problem. 
YOUR MILAGE MAY VARY.  But _I_ have personally not had problems doing this.

>The only reference I've seen to buffering is the "U" on the end of the part 
>number before the A or B,  and that only on the 4069UB for some reason.
>
>> You can only know the voltage range by getting the data sheet.  I have a
>> habit of downloading the PDF files for everything I use and keeping them
>> here.  "UB" at the end means unbuffered and have some interesting uses. 
>> Eg., the 4069UB can be used as a "linear amplifier" (see data sheet) which
>> works kind of like an opamp.  It has an interesting was of distorting, more
>> like vacuum tube soft clipping.
>
>Now I remember *that* one from Craig Anderton's book.  :-)
>
>Don Lancaster also talked about using these parts in linear mode as well, and 
>you can make some mighty simple oscillators if the requirements aren't 
>critical -- a couple of inverters,  one cap,  and one resistor,  if I'm 
>remebering right.  (I've gotten into this nasty habit lately of not bothering 
>to remember much,  figuring I can refer to the book if need be.  :-)

The René Schmitz 4069UB VCO works this way, using one gate for an integrator and
2 for a Schmitt trigger, the other 3 are used for part of a PWM circuit.


>Got any particularly good sources for data sheets and app notes?  I'm familiar 
>with Dial,  but they have an awful lot of gaps in there and there was one 
>other I hit recently,  but I can't recall where it was offhand.

I just google, usually I find a free PDF within the first page of hits.

Then I save it because there's no guarantee it will stay there.  I think that
many of us here have collections of these, so if you bump up against an
impossible to find one, a plea for help here will work.  I have 87 PDFs in my
collection.


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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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