19 Dec
2006
19 Dec
'06
2:54 p.m.
Date: Tue, 19 Dec 2006 10:30:36 -0700
From: Richard <legalize at xmission.com>
In article <458726D7.17136.1434D6AA at
cclist.sydex.com>,
"Chuck Guzis" <cclist at sydex.com> writes:
Is there a guide somewhere to the different families of logic, such
as RTL, TTL, LSTTL (never heard of that one) and CMOS? I was
choosing some simple logic components for my IIfx SIMM project the
other day and was somewhat bewildered by the choice of input/output
levels. Also, some are Schmidt Triggered?
My understanding extends to the idea that there are differences in
how they (at what voltage) interpret the low and high states but
beyond that, I'm ignorant.
Anyway, before I go on a Google hunt (which will probably turn up all
the surplus electronics suppliers and pricegrabber links first) does
anyone already know of a nice educational source on the topic?
Jeff Walther
But, given that the original uses RTL and core,
what's the point of
building one in LSTTL?
Is it even possible to build with RTL parts anymore?
I guess you'd have to do it PDP-8 style with discrete transistors? 
19 Dec
19 Dec
3:01 p.m.
Is there a guide somewhere to the different families
of logic, such
as RTL, TTL, LSTTL (never heard of that one)
LSTTL = Low-power Schottky TTL: basically, TTL done with low-power
Schottky technology. (http://en.wikipedia.org/wiki/Schottky_barrier
has more than you probably want to know about what Schottky means as
applied to semiconductor logic.)
Also, some are Schmidt Triggered?
(Schmitt, I think.) I suspect most logic families have something
functionally equivalent to Schmitt triggers (inputs with hysteresis).
As for a guide to the families, I can't help much there. I know that
there exists CMOS which is signal-level-compatible with TTL (I think
they're the 74HCT parts), but that's about where my knowledge ends.
You might also add ECL to your list. It stands for Emitter-Coupled
Logic, and I have gained the impression that it's fast and
power-hungry, but further deponent sayeth not.
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3:41 p.m.
der Mouse wrote:
LS usually has the speed of TTL with the power dissipation of L.
Other variations:
74Hxx
74Lxx
74Sxx
74ASxx
74ALSxx
74Cxx
ECL is fast because it doesn't put the transistors into saturation or
cutoff (ie it's operating in the "linear region"). This means that no
time is required to move "large" amounts of charge (electrons) into or
out of the base of the transistor which is necessary to "saturate" the
transistor. This is why it is so power hungry...it's operating in the
"linear" region so current is always flowing through it and it's acting
as a resistor (ie causing a voltage drop across the part).
--
TTFN - Guy
Is there a
guide somewhere to the different families of logic, such
as RTL, TTL, LSTTL (never heard of that one)
LSTTL = Low-power Schottky TTL: basically, TTL done with low-power
Schottky technology. (http://en.wikipedia.org/wiki/Schottky_barrier
has more than you probably want to know about what Schottky means as
applied to semiconductor logic.)
Also, some are Schmidt Triggered?
(Schmitt, I think.) I suspect most logic families have something
functionally equivalent to Schmitt triggers (inputs with hysteresis).
As for a guide to the families, I can't help much there. I know that
there exists CMOS which is signal-level-compatible with TTL (I think
they're the 74HCT parts), but that's about where my knowledge ends.
You might also add ECL to your list. It stands for Emitter-Coupled
Logic, and I have gained the impression that it's fast and
power-hungry, but further deponent sayeth not.
6:57 p.m.
On 19 Dec 2006 at 15:41, Guy Sotomayor wrote:
LS usually has the speed of TTL with the power
dissipation of L.
Other variations:
74Hxx
74Lxx
74Sxx
74ASxx
74ALSxx
74Cxx
74F is another common one. Normally, one can assume that the
pinout's the same between all families, regardless of the letters
after the "74". The notable exception is 74L--some members of the
family have pinouts that differ from the corresponding 74/74S/74LS
ones. e.g., 74L85 vs. 7485.
Similarly, 74 and 74-followed-by-alphabet-soup ICs can differ in
implementation. Some notable examples are 7473--positive pulse-
triggered JK FF; 74LS73 negative-edge-triggered JK FF.
And again, one could get away with wire-OR-in 74L-series logic, which
would be a disaster in any other 74-series logic family.
Just a gentle reminder to check the databook before cross-
substituting...
Cheers,
Chuck
31 Dec
31 Dec
12:13 p.m.
Guy Sotomayor wrote:
ECL is fast because it doesn't put the transistors
into saturation or
cutoff (ie it's operating in the "linear region"). This means that no
time is required to move "large" amounts of charge (electrons) into or
out of the base of the transistor which is necessary to "saturate" the
transistor. This is why it is so power hungry...it's operating in the
"linear" region so current is always flowing through it and it's acting
as a resistor (ie causing a voltage drop across the part).
But where can you get them cheap? $10 a chip is not cheap.
Note at one time I read about ECL PALS. That sounds nice if you
could still get that.
19 Dec
19 Dec
3:19 p.m.
In article <a04310101c1ae1d26d8fb(a)[192.168.1.3]>3]>,
Jeff Walther <trag at io.com> writes:
Is there a guide somewhere to the different families
of logic, such
as RTL, TTL, LSTTL (never heard of that one) and CMOS?
Wikipedia has fairly good entries for these.
--
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3:28 p.m.
On 19 Dec 2006 at 16:54, Jeff Walther wrote:
Is there a guide somewhere to the different families
of logic, such
as RTL, TTL, LSTTL (never heard of that one) and CMOS? I was
choosing some simple logic components for my IIfx SIMM project the
other day and was somewhat bewildered by the choice of input/output
levels. Also, some are Schmidt Triggered?
SIgh. Googling around, I find not a lot of detail on the logic
families, or that they've now become the exclusive domain of
engineering textbook writers and EE professors.
If you can get your hands on one, the big old Motorola Integrated
Circuit data book from about 1969 is an excellent reference on RTL,
ECL, DTL, HTL, TTL and even some MOS (not CMOS). While a few things
have been added (like CMOS logic), the basic principles of operation
haven't changed much.
The very interesting thing about RTL was that the ICs could be
operated in the linear region for lots of non-logic applications.
Cheers,
Chuck
20 Dec
20 Dec
8:21 a.m.
On Tue, 19 Dec 2006 15:28:31 -0800
"Chuck Guzis" <cclist at sydex.com> wrote:
The very interesting thing about RTL was that the ICs
could be
operated in the linear region for lots of non-logic applications.
Now that is something I didn't know and find very much worth looking
into. Any quick pointers to info on RTL operating in this mode?
Thanks,
jbdigriz
11:28 a.m.
On 20 Dec 2006 at 11:21, James B. DiGriz wrote:
Now that is something I didn't know and find very
much worth looking
into. Any quick pointers to info on RTL operating in this mode?
I'll dig through my old literature. I recall that Motorola offered
an "Experimenter's Kit" of about 6 of their TO-99 packaged milliwatt
RTL circuits with some non-digital application notes.
Anyone still have the little booklet that came with this kit?
Cheers,
Chuck
1:45 p.m.
New subject: RTL, was Re: Build your own Apollo Guidance Computer
"James B. DiGriz" wrote:
On Tue, 19 Dec 2006 15:28:31 -0800
"Chuck Guzis" <cclist at sydex.com> wrote:
Don't know about anything online, but in print keep your eye out for a copy of
Don Lancaster's "RTL Cookbook" (Sams, 1969), the predecessor to his better
known "TTL Cookbook". There's a chapter on "Linear Circuits and
Techniques".
Mostly it's just biasing an inverter into the linear region with a resistor
to + on the input, but one of the cute tricks is to take two inverters in the
same package, raise the GND pin (common emitter) above circuit GND with a
resistor and so make a differential amplifier
(...on the other hand, the 709 was around at that time...)
Chuck Guzis wrote:
The very interesting thing about RTL was that the
ICs could be
operated in the linear region for lots of non-logic applications.
Now that is something I didn't know and find very much worth looking
into. Any quick pointers to info on RTL operating in this mode? I'll dig through my old literature. I recall that
Motorola offered
an "Experimenter's Kit" of about 6 of their TO-99 packaged milliwatt
RTL circuits with some non-digital application notes.
Anyone still have the little booklet that came with
this kit?
Bubble pack on mauve-colored cardboard backing?
"Motorola HEP Integrated Circuit Experimenter Kit"
"5 Prime Quality RTL I/C's"
"$3.95"
I have two unopened packs, the staple holes are present in the cardboard where
presumably the booklet was attached, but the booklet is gone.
2:06 p.m.
New subject: RTL, was Re: Build your own Apollo Guidance Computer
On 20 Dec 2006 at 13:45, Brent Hilpert wrote:
Bubble pack on mauve-colored cardboard backing?
"Motorola HEP Integrated Circuit Experimenter Kit"
"5 Prime Quality RTL I/C's"
"$3.95"
I have two unopened packs, the staple holes are present in the cardboard where
presumably the booklet was attached, but the booklet is gone.
That's the one--and come to think of it, the ICs are probably TO-100
packaging, not TO-99. Too bad about the booklet, however.
Cheers,
Chuck
19 Dec
19 Dec
3:49 p.m.
Jeff Walther wrote:
Is there a guide somewhere to the different families of logic, such
as RTL, TTL, LSTTL (never heard of that one) and CMOS? I was
choosing some simple logic components for my IIfx SIMM project the
other day and was somewhat bewildered by the choice of input/output
levels. Also, some are Schmidt Triggered?
My understanding extends to the idea that there are differences in
how they (at what voltage) interpret the low and high states but
beyond that, I'm ignorant.
Anyway, before I go on a Google hunt (which will probably turn up all
the surplus electronics suppliers and pricegrabber links first) does
anyone already know of a nice educational source on the topic?
Most books or course material about digital logic from around the 70s tend to
have an overview of the major logic families,
for example "Integrated Circuits" by Robert G. Hibberd, published by
McGraw-Hill 1969, but produced by Texas Instruments.
IMHO, for earlier stuff, some of the nicest treatises on a specific logic
family are the first/introductory chapters of Fairchild data books from the
60s and 70s.
(...and don't forget DCTL, RCTL, DTL, CTL, ECL, PMOS, variations on all of the
preceding, ...)
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11 comments
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bfranchuk＠jetnet.ab.ca -
cclist＠sydex.com -
ggs＠shiresoft.com -
hilpert＠cs.ubc.ca -
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