WAYNE CHIRNSIDE wrote in a message to ROY J. TELLASON:

-=> JASEN BETTS wrote to ROY J. TELLASON <=-

 RJT> One is a chip resembling an op amp,  but apparently preconfigured
 RJT> as a unity-gain buffer.  I found it easily enough in my
 RJT> databooks, though I don't know why you'd get these and not just
 RJT> use a standard op amp and configure it as a unity gain part.
 RJT> Maybe some difference in the spec that's not apparent to me, or
 RJT> something...    (Anybody know?)   I suppose I'll think of
 RJT> something to do with these sooner or later

 WC> Designed for better wideband response at unity, not so easy to
 WC> achieve. Also to reduce output impedence which can alter
 WC> the linear response and behavior of subsequent circuitry.

Yeah,  but I can't think of anything where I'd _need_ something like that...

 RJT> The other part that jumped out at me as being a little unique was
 RJT> a 565 PLL chip.  I have heard of this one before,  but have *no*
 RJT> idea what you'd do with it.  Any of you guys have any thoughts on
 RJT> the matter

 WC> A fairly low frequency demodulator chip IIRC.
 WC> Likely about the same as you could with a CMOS 4046 which I've more
 WC> experience with.

I've yet to get a hold of some of those.  I did find a can of CMOS chips, 
and looked through them earlier today.  No PLLs in there but there seems to
be one heck of a lot of 4066 chips for some reason.    Outside of
that,  just a few gates...

 WC> Built a Hi-Fi audio link that used a 4046 PLL at either end. Got
 WC> well over 1,000 feet range with just a LED and a 3" glass lens at
 WC> one end and far smaller lens at transmitter end.

 JB> ISTR that a PLL is a kind of frequency follower, other than using it in
 JB> a frequency synthesiser (in a radio tuner) or frequency multiplier etc
 JB> I don't know what you could do with it,

 WC>  Provides a voltage output from it's filter that's proportional to 
 WC> it's center frequency and incoming frequency. I used this in my 
 WC> lightwave communications link feeding the voltage follower on that 
 WC> filter directly into an audio amplifier. Remote telemetry is 
 WC> another use such a circuit suggests to me.

 WC>  The filter supplies the voltage that drives the tracking VCO and 
 WC> that filter must be responsive enought to keep the phase shift 
 WC> between input and VCO between limits or the phase lock loop loses 
 WC> lock.

 WC>  The 4046 I messed with had stable lock at 90 degrees of shift 
 WC> between input and VCO and could go to just shy of zero or 180 
 WC> degrees before losing lock.

 JB> HMM, maybe you've got a parallel-port radio tuner kit there.

I'll figure out something to do with it...

After the CMOS can and the TTL can there was the linear can,  and I've
found some interesting stuff in there.  I'm still sorting things out,  but
aside from the op amps and voltage regulators (more 7805s and 7812s than
I'll probably ever use :-) there were some audio amp chips,  and some other
ones I couldn't find anywhere (yet).  One I just snagged a datasheet for is
the CA3094,  apparently another OTA?  I never did do too much with the
3080,  the first of that sort of chip I ran into.  It was hard to not have
seriously heavy distortion coming out of that thing,  I guess maybe some
application notes might help.  I wish I'd been able to snag this stuff off
the 'net ages ago!  :-)

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