MIKE ROSS wrote in a message to Greg Mayman:

 MR> "Greg Mayman" bravely wrote to "Roy J.
Tellason" (21 Jan 04 
 MR> 08:17:00)  --- on the heady topic of "BAG OF CHIPS"

 GM> There aren't many integrated PLLs that work a lot higher. The
 GM> 4046 only goes to 0.7MHz typically.

 MR> It can be pushed to 2 or 3Mz if the heat is taken away from the
 MR> package. I tested it running that high but it uses a lot more
 MR> current and thus the extra heat. We're just not used to putting a
 MR> heatsink on a 4000 series chip but intel does it on their cpu's...
 MR> BTW I do remember heatsinking my overclocked 8088's and then my
 MR> V20's. Nothing new there, eh?

Got this book on the subject,  though I'm a lot less interested in pushing
my luck by overclocking and more interested in the "optimizing"
and "tweaks" portion of that stuff.  And the one thing they do
keep hammering on over and over is the need for removing the heat.  Also
saying that raising the supply voltage (or the core voltage in the case of
a cpu) might help.  I guess CMOS does better at higher voltages too,  come
to think of it.

Speaking of which,  the original 4000 series stuff was good to 15V max, 
then they came out with the "B" series devices that were maxed
out at 18V,  I wonder why they never pushed that any further?  And from the
few data sheets I've managed to get a hold of,  it appears that some of the
7400-type CMOS parts are limited to 7V max just like TTL.  How odd.

I still haven't got it all sorted out in my head about 74C, 74HC, and
74HCT,  except for knowing that the last one is supposed to be
TTL-compatible,  but whether that's on the input side,  the output side, 
or both I have yet to determine.

---