<s>
In	O
computer	O
engineering	O
,	O
a	O
logic	B-General_Concept
family	I-General_Concept
is	O
one	O
of	O
two	O
related	O
concepts	O
:	O
</s>
<s>
A	O
logic	B-General_Concept
family	I-General_Concept
of	O
monolithic	O
digital	O
integrated	O
circuit	O
devices	O
is	O
a	O
group	O
of	O
electronic	O
logic	O
gates	O
constructed	O
using	O
one	O
of	O
several	O
different	O
designs	O
,	O
usually	O
with	O
compatible	O
logic	O
levels	O
and	O
power	O
supply	O
characteristics	O
within	O
a	O
family	O
.	O
</s>
<s>
Many	O
logic	B-General_Concept
families	I-General_Concept
were	O
produced	O
as	O
individual	O
components	O
,	O
each	O
containing	O
one	O
or	O
a	O
few	O
related	O
basic	O
logical	O
functions	O
,	O
which	O
could	O
be	O
used	O
as	O
"	O
building-blocks	O
"	O
to	O
create	O
systems	O
or	O
as	O
so-called	O
"	O
glue	O
"	O
to	O
interconnect	O
more	O
complex	O
integrated	O
circuits	O
.	O
</s>
<s>
A	O
logic	B-General_Concept
family	I-General_Concept
may	O
also	O
be	O
a	O
set	O
of	O
techniques	O
used	O
to	O
implement	O
logic	O
within	O
VLSI	O
integrated	O
circuits	O
such	O
as	O
central	O
processors	O
,	O
memories	O
,	O
or	O
other	O
complex	O
functions	O
.	O
</s>
<s>
Some	O
such	O
logic	B-General_Concept
families	I-General_Concept
use	O
static	O
techniques	O
to	O
minimize	O
design	O
complexity	O
.	O
</s>
<s>
Other	O
such	O
logic	B-General_Concept
families	I-General_Concept
,	O
such	O
as	O
domino	B-General_Concept
logic	I-General_Concept
,	O
use	O
clocked	B-General_Concept
dynamic	I-General_Concept
techniques	I-General_Concept
to	O
minimize	O
size	O
,	O
power	O
consumption	O
and	O
delay	O
.	O
</s>
<s>
The	O
most	O
common	O
logic	B-General_Concept
family	I-General_Concept
in	O
modern	O
semiconductor	O
devices	O
is	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
(	O
MOS	O
)	O
logic	O
,	O
due	O
to	O
low	O
power	O
consumption	O
,	O
small	O
transistor	B-Application
sizes	O
,	O
and	O
high	O
transistor	B-Application
density	O
.	O
</s>
<s>
The	O
list	O
of	O
packaged	O
building-block	O
logic	B-General_Concept
families	I-General_Concept
can	O
be	O
divided	O
into	O
categories	O
,	O
listed	O
here	O
in	O
roughly	O
chronological	O
order	O
of	O
introduction	O
,	O
along	O
with	O
their	O
usual	O
abbreviations	O
:	O
</s>
<s>
The	O
families	O
(	O
RTL	O
,	O
DTL	B-General_Concept
,	O
and	O
ECL	O
)	O
were	O
derived	O
from	O
the	O
logic	O
circuits	O
used	O
in	O
early	O
computers	O
,	O
originally	O
implemented	O
using	O
discrete	O
components	O
.	O
</s>
<s>
The	O
PMOS	O
and	O
I2L	B-General_Concept
logic	B-General_Concept
families	I-General_Concept
were	O
used	O
for	O
relatively	O
short	O
periods	O
,	O
mostly	O
in	O
special	O
purpose	O
custom	O
large-scale	O
integration	O
circuits	O
devices	O
and	O
are	O
generally	O
considered	O
obsolete	O
.	O
</s>
<s>
The	O
F14	B-Device
CADC	I-Device
,	O
Intel	B-General_Concept
4004	I-General_Concept
,	O
Intel	B-General_Concept
4040	I-General_Concept
,	O
and	O
Intel	B-General_Concept
8008	I-General_Concept
microprocessors	B-Architecture
and	O
their	O
support	O
chips	O
were	O
PMOS	O
.	O
</s>
<s>
Of	O
these	O
families	O
,	O
only	O
ECL	O
,	O
TTL	B-General_Concept
,	O
NMOS	O
,	O
CMOS	B-Device
,	O
and	O
BiCMOS	B-General_Concept
are	O
currently	O
still	O
in	O
widespread	O
use	O
.	O
</s>
<s>
ECL	O
is	O
used	O
for	O
very	O
high-speed	O
applications	O
because	O
of	O
its	O
price	O
and	O
power	O
demands	O
,	O
while	O
NMOS	B-Algorithm
logic	I-Algorithm
is	O
mainly	O
used	O
in	O
VLSI	O
circuits	O
applications	O
such	O
as	O
CPUs	B-Device
and	O
memory	O
chips	O
which	O
fall	O
outside	O
of	O
the	O
scope	O
of	O
this	O
article	O
.	O
</s>
<s>
Present-day	O
"	O
building	O
block	O
"	O
logic	O
gate	O
ICs	O
are	O
based	O
on	O
the	O
ECL	O
,	O
TTL	B-General_Concept
,	O
CMOS	B-Device
,	O
and	O
BiCMOS	B-General_Concept
families	O
.	O
</s>
<s>
Class	O
of	O
digital	O
circuits	O
built	O
using	O
resistors	O
as	O
the	O
input	O
network	O
and	O
bipolar	O
junction	O
transistors	B-Application
(	O
BJTs	O
)	O
as	O
switching	O
devices	O
.	O
</s>
<s>
The	B-Device
Atanasoff	I-Device
–	I-Device
Berry	I-Device
Computer	I-Device
used	O
resistor-coupled	O
vacuum	O
tube	O
logic	O
circuits	O
similar	O
to	O
RTL	O
.	O
</s>
<s>
Several	O
early	O
transistorized	O
computers	O
(	O
e.g.	O
,	O
IBM	B-Device
1620	I-Device
,	O
1959	O
)	O
used	O
RTL	O
,	O
where	O
it	O
was	O
implemented	O
using	O
discrete	O
components	O
.	O
</s>
<s>
A	O
family	O
of	O
simple	O
resistor	O
–	O
transistor	B-Application
logic	O
integrated	O
circuits	O
was	O
developed	O
at	O
Fairchild	O
Semiconductor	O
for	O
the	O
Apollo	B-Application
Guidance	I-Application
Computer	I-Application
in	O
1962	O
.	O
</s>
<s>
Class	O
of	O
digital	O
circuits	O
in	O
which	O
the	O
logic	O
gating	O
function	O
(	O
e.g.	O
,	O
AND	O
)	O
is	O
performed	O
by	O
a	O
diode	O
network	O
and	O
the	O
amplifying	O
function	O
is	O
performed	O
by	O
a	O
transistor	B-Application
.	O
</s>
<s>
Diode	B-General_Concept
logic	I-General_Concept
was	O
used	O
with	O
vacuum	O
tubes	O
in	O
the	O
earliest	O
electronic	O
computers	O
in	O
the	O
1940s	O
including	O
ENIAC	B-Device
.	O
</s>
<s>
Diode	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
(	O
DTL	B-General_Concept
)	O
was	O
used	O
in	O
the	O
IBM	B-Device
608	I-Device
which	O
was	O
the	O
first	O
all-transistorized	O
computer	O
.	O
</s>
<s>
Early	O
transistorized	O
computers	O
were	O
implemented	O
using	O
discrete	O
transistors	B-Application
,	O
resistors	O
,	O
diodes	O
and	O
capacitors	O
.	O
</s>
<s>
The	O
first	O
diode	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
family	O
of	O
integrated	O
circuits	O
was	O
introduced	O
by	O
Signetics	O
in	O
1962	O
.	O
</s>
<s>
DTL	B-General_Concept
was	O
also	O
made	O
by	O
Fairchild	O
and	O
Westinghouse	O
.	O
</s>
<s>
A	O
family	O
of	O
diode	B-General_Concept
logic	I-General_Concept
and	O
diode	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
integrated	O
circuits	O
was	O
developed	O
by	O
Texas	O
Instruments	O
for	O
the	O
D-37C	O
Minuteman	O
II	O
Guidance	O
Computer	O
in	O
1962	O
,	O
but	O
these	O
devices	O
were	O
not	O
available	O
to	O
the	O
public	O
.	O
</s>
<s>
A	O
variant	O
of	O
DTL	B-General_Concept
called	O
"	O
high-threshold	B-General_Concept
logic	I-General_Concept
"	O
incorporated	O
Zener	O
diodes	O
to	O
create	O
a	O
large	O
offset	O
between	O
logic	O
1	O
and	O
logic	O
0	O
voltage	O
levels	O
.	O
</s>
<s>
P-type	B-Algorithm
MOS	I-Algorithm
(	O
PMOS	O
)	O
logic	O
uses	O
p-channel	O
MOSFETs	B-Architecture
to	O
implement	O
logic	O
gates	O
and	O
other	O
digital	O
circuits	O
.	O
</s>
<s>
N-type	B-Algorithm
MOS	I-Algorithm
(	O
NMOS	O
)	O
logic	O
uses	O
n-channel	O
MOSFETs	B-Architecture
to	O
implement	O
logic	O
gates	O
and	O
other	O
digital	O
circuits	O
.	O
</s>
<s>
For	O
devices	O
of	O
equal	O
current	O
driving	O
capability	O
,	O
n-channel	O
MOSFETs	B-Architecture
can	O
be	O
made	O
smaller	O
than	O
p-channel	O
MOSFETs	B-Architecture
,	O
due	O
to	O
p-channel	O
charge	O
carriers	O
(	O
holes	O
)	O
having	O
lower	O
mobility	O
than	O
do	O
n-channel	O
charge	O
carriers	O
(	O
electrons	O
)	O
,	O
and	O
producing	O
only	O
one	O
type	O
of	O
MOSFET	B-Architecture
on	O
a	O
silicon	O
substrate	O
is	O
cheaper	O
and	O
technically	O
simpler	O
.	O
</s>
<s>
These	O
were	O
the	O
driving	O
principles	O
in	O
the	O
design	O
of	O
NMOS	B-Algorithm
logic	I-Algorithm
which	O
uses	O
n-channel	O
MOSFETs	B-Architecture
exclusively	O
.	O
</s>
<s>
However	O
,	O
neglecting	O
leakage	O
current	O
,	O
unlike	O
CMOS	B-Device
logic	O
,	O
NMOS	B-Algorithm
logic	I-Algorithm
consumes	O
power	O
even	O
when	O
no	O
switching	O
is	O
taking	O
place	O
.	O
</s>
<s>
Mohamed	O
M	O
.	O
Atalla	O
and	O
Dawon	O
Kahng	O
,	O
after	O
they	O
invented	O
the	O
MOSFET	B-Architecture
,	O
fabricated	B-Architecture
both	O
pMOS	O
and	O
nMOS	O
devices	O
with	O
a	O
20	O
µm	O
process	O
in	O
1960	O
.	O
</s>
<s>
Their	O
original	O
MOSFET	B-Architecture
devices	O
had	O
a	O
gate	O
length	O
of	O
20µm	O
and	O
a	O
gate	B-Algorithm
oxide	I-Algorithm
thickness	O
of	O
100	O
nm	O
.	O
</s>
<s>
NMOS	O
was	O
initially	O
faster	O
than	O
CMOS	B-Device
,	O
thus	O
NMOS	O
was	O
more	O
widely	O
used	O
for	O
computers	O
in	O
the	O
1970s	O
.	O
</s>
<s>
With	O
advances	O
in	O
technology	O
,	O
CMOS	B-Device
logic	O
displaced	O
NMOS	B-Algorithm
logic	I-Algorithm
in	O
the	O
mid-1980s	O
to	O
become	O
the	O
preferred	O
process	O
for	O
digital	O
chips	O
.	O
</s>
<s>
ECL	O
uses	O
an	O
overdriven	O
bipolar	O
junction	O
transistor	B-Application
(	O
BJT	O
)	O
differential	O
amplifier	O
with	O
single-ended	O
input	O
and	O
limited	O
emitter	O
current	O
.	O
</s>
<s>
The	O
ECL	O
family	O
,	O
ECL	O
is	O
also	O
known	O
as	O
current-mode	O
logic	O
(	O
CML	O
)	O
,	O
was	O
invented	O
by	O
IBM	O
as	O
current	B-General_Concept
steering	I-General_Concept
logic	I-General_Concept
for	O
use	O
in	O
the	O
transistorized	O
IBM	B-Device
7030	I-Device
Stretch	I-Device
computer	O
,	O
where	O
it	O
was	O
implemented	O
using	O
discrete	O
components	O
.	O
</s>
<s>
The	O
first	O
ECL	O
logic	B-General_Concept
family	I-General_Concept
to	O
be	O
available	O
in	O
integrated	O
circuits	O
was	O
introduced	O
by	O
Motorola	O
as	O
MECL	O
in	O
1962	O
.	O
</s>
<s>
In	O
TTL	B-General_Concept
logic	I-General_Concept
,	O
bipolar	O
junction	O
transistors	B-Application
perform	O
the	O
logic	O
and	O
amplifying	O
functions	O
.	O
</s>
<s>
The	O
first	O
transistor	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
family	O
of	O
integrated	O
circuits	O
was	O
introduced	O
by	O
Sylvania	O
as	O
Sylvania	O
Universal	O
High	O
–	O
Level	O
Logic	O
(	O
SUHL	O
)	O
in	O
1963	O
.	O
</s>
<s>
Texas	O
Instruments	O
introduced	O
the	O
7400	O
series	O
TTL	B-General_Concept
family	O
in	O
1964	O
.	O
</s>
<s>
Transistor	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
uses	O
bipolar	O
transistors	B-Application
to	O
form	O
its	O
integrated	O
circuits	O
.	O
</s>
<s>
TTL	B-General_Concept
has	O
changed	O
significantly	O
over	O
the	O
years	O
,	O
with	O
newer	O
versions	O
replacing	O
the	O
older	O
types	O
.	O
</s>
<s>
Since	O
the	O
transistors	B-Application
of	O
a	O
standard	O
TTL	B-General_Concept
gate	O
are	O
saturated	O
switches	O
,	O
minority	O
carrier	O
storage	O
time	O
in	O
each	O
junction	O
limits	O
the	O
switching	O
speed	O
of	O
the	O
device	O
.	O
</s>
<s>
Variations	O
on	O
the	O
basic	O
TTL	B-General_Concept
design	O
are	O
intended	O
to	O
reduce	O
these	O
effects	O
and	O
improve	O
speed	O
,	O
power	O
consumption	O
,	O
or	O
both	O
.	O
</s>
<s>
The	O
German	O
physicist	O
Walter	O
H	O
.	O
Schottky	O
formulated	O
a	O
theory	O
predicting	O
the	O
Schottky	O
effect	O
,	O
which	O
led	O
to	O
the	O
Schottky	O
diode	O
and	O
later	O
Schottky	O
transistors	B-Application
.	O
</s>
<s>
For	O
the	O
same	O
power	B-General_Concept
dissipation	I-General_Concept
,	O
Schottky	O
transistors	B-Application
have	O
a	O
faster	O
switching	O
speed	O
than	O
conventional	O
transistors	B-Application
because	O
the	O
Schottky	O
diode	O
prevents	O
the	O
transistor	B-Application
from	O
saturating	O
and	O
storing	O
charge	O
;	O
see	O
Baker	O
clamp	O
.	O
</s>
<s>
Gates	O
built	O
with	O
Schottky	O
transistors	B-Application
use	O
more	O
power	O
than	O
normal	O
TTL	B-General_Concept
and	O
switch	O
faster	O
.	O
</s>
<s>
A	O
faster	O
logic	B-General_Concept
family	I-General_Concept
called	O
FAST	O
(	O
Fairchild	O
Advanced	O
Schottky	O
TTL	B-General_Concept
)	O
(	O
Schottky	O
)	O
(	O
F	O
)	O
was	O
also	O
introduced	O
that	O
was	O
faster	O
than	O
normal	O
Schottky	O
TTL	B-General_Concept
.	O
</s>
<s>
CMOS	B-Device
logic	O
gates	O
use	O
complementary	O
arrangements	O
of	O
enhancement-mode	O
N-channel	O
and	O
P-channel	O
field	O
effect	O
transistor	B-Application
.	O
</s>
<s>
Since	O
the	O
initial	O
devices	O
used	O
oxide-isolated	O
metal	O
gates	O
,	O
they	O
were	O
called	O
CMOS	B-Device
(	O
complementary	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
logic	O
)	O
.	O
</s>
<s>
In	O
contrast	O
to	O
TTL	B-General_Concept
,	O
CMOS	B-Device
uses	O
almost	O
no	O
power	O
in	O
the	O
static	O
state	O
(	O
that	O
is	O
,	O
when	O
inputs	O
are	O
not	O
changing	O
)	O
.	O
</s>
<s>
A	O
CMOS	B-Device
gate	O
draws	O
no	O
current	O
other	O
than	O
leakage	O
when	O
in	O
a	O
steady	O
1	O
or	O
0	O
state	O
.	O
</s>
<s>
This	O
means	O
that	O
the	O
current	O
draw	O
of	O
CMOS	B-Device
devices	O
increases	O
with	O
switching	O
rate	O
(	O
controlled	O
by	O
clock	O
speed	O
,	O
typically	O
)	O
.	O
</s>
<s>
The	O
first	O
CMOS	B-Device
family	O
of	O
logic	O
integrated	O
circuits	O
was	O
introduced	O
by	O
RCA	O
as	O
CD4000	O
COS/MOS	O
,	O
the	O
4000	O
series	O
,	O
in	O
1968	O
.	O
</s>
<s>
Initially	O
CMOS	B-Device
logic	O
was	O
slower	O
than	O
LS-TTL	O
.	O
</s>
<s>
However	O
,	O
because	O
the	O
logic	O
thresholds	O
of	O
CMOS	B-Device
were	O
proportional	O
to	O
the	O
power	O
supply	O
voltage	O
,	O
CMOS	B-Device
devices	O
were	O
well-adapted	O
to	O
battery-operated	O
systems	O
with	O
simple	O
power	O
supplies	O
.	O
</s>
<s>
CMOS	B-Device
gates	O
can	O
also	O
tolerate	O
much	O
wider	O
voltage	O
ranges	O
than	O
TTL	B-General_Concept
gates	O
because	O
the	O
logic	O
thresholds	O
are	O
(	O
approximately	O
)	O
proportional	O
to	O
power	O
supply	O
voltage	O
,	O
and	O
not	O
the	O
fixed	O
levels	O
required	O
by	O
bipolar	O
circuits	O
.	O
</s>
<s>
The	O
required	O
silicon	O
area	O
for	O
implementing	O
such	O
digital	O
CMOS	B-Device
functions	O
has	O
rapidly	O
shrunk	O
.	O
</s>
<s>
VLSI	O
technology	O
incorporating	O
millions	O
of	O
basic	O
logic	O
operations	O
onto	O
one	O
chip	O
,	O
almost	O
exclusively	O
uses	O
CMOS	B-Device
.	O
</s>
<s>
CMOS	B-Device
chips	O
often	O
work	O
with	O
a	O
broader	O
range	O
of	O
power	O
supply	O
voltages	O
than	O
other	O
logic	B-General_Concept
families	I-General_Concept
.	O
</s>
<s>
Early	O
TTL	B-General_Concept
ICs	O
required	O
a	O
power	O
supply	O
voltage	O
of	O
5V	O
,	O
but	O
early	O
CMOS	B-Device
could	O
use	O
3	O
to	O
15V	O
.	O
</s>
<s>
By	O
lowering	O
the	O
power	O
supply	O
from	O
5V	O
to	O
3.3V	O
,	O
switching	O
power	O
was	O
reduced	O
by	O
almost	O
60	O
percent	O
(	O
power	B-General_Concept
dissipation	I-General_Concept
is	O
proportional	O
to	O
the	O
square	O
of	O
the	O
supply	O
voltage	O
)	O
.	O
</s>
<s>
Many	O
motherboards	O
have	O
a	O
voltage	O
regulator	O
module	O
to	O
provide	O
the	O
even	O
lower	O
power	O
supply	O
voltages	O
required	O
by	O
many	O
CPUs	B-Device
.	O
</s>
<s>
Because	O
of	O
the	O
incompatibility	O
of	O
the	O
CD4000	O
series	O
of	O
chips	O
with	O
the	O
previous	O
TTL	B-General_Concept
family	O
,	O
a	O
new	O
standard	O
emerged	O
which	O
combined	O
the	O
best	O
of	O
the	O
TTL	B-General_Concept
family	O
with	O
the	O
advantages	O
of	O
the	O
CD4000	O
family	O
.	O
</s>
<s>
It	O
was	O
known	O
as	O
the	O
74HC	O
(	O
which	O
used	O
anywhere	O
from	O
3.3V	O
to	O
5V	O
power	O
supplies	O
(	O
and	O
used	O
logic	O
levels	O
relative	O
to	O
the	O
power	O
supply	O
)	O
)	O
,	O
and	O
with	O
devices	O
that	O
used	O
5V	O
power	O
supplies	O
and	O
TTL	B-General_Concept
logic	I-General_Concept
levels	O
.	O
</s>
<s>
Interconnecting	O
any	O
two	O
logic	B-General_Concept
families	I-General_Concept
often	O
required	O
special	O
techniques	O
such	O
as	O
additional	O
pull-up	O
resistors	O
,	O
or	O
purpose-built	O
interface	O
circuits	O
,	O
since	O
the	O
logic	B-General_Concept
families	I-General_Concept
may	O
use	O
different	O
voltage	O
levels	O
to	O
represent	O
1	O
and	O
0	O
states	O
,	O
and	O
may	O
have	O
other	O
interface	O
requirements	O
only	O
met	O
within	O
the	O
logic	B-General_Concept
family	I-General_Concept
.	O
</s>
<s>
TTL	B-General_Concept
logic	I-General_Concept
levels	O
are	O
different	O
from	O
those	O
of	O
CMOS	B-Device
–	O
generally	O
a	O
TTL	B-General_Concept
output	O
does	O
not	O
rise	O
high	O
enough	O
to	O
be	O
reliably	O
recognized	O
as	O
a	O
logic	O
1	O
by	O
a	O
CMOS	B-Device
input	O
.	O
</s>
<s>
This	O
problem	O
was	O
solved	O
by	O
the	O
invention	O
of	O
the	O
74HCT	O
family	O
of	O
devices	O
that	O
uses	O
CMOS	B-Device
technology	O
but	O
TTL	B-General_Concept
input	O
logic	O
levels	O
.	O
</s>
<s>
They	O
form	O
a	O
replacement	O
for	O
TTL	B-General_Concept
,	O
although	O
HCT	O
is	O
slower	O
than	O
original	O
TTL	B-General_Concept
(	O
HC	O
logic	O
has	O
about	O
the	O
same	O
speed	O
as	O
original	O
TTL	B-General_Concept
)	O
.	O
</s>
<s>
Other	O
CMOS	B-Device
circuit	O
families	O
within	O
integrated	O
circuits	O
include	O
cascode	B-General_Concept
voltage	I-General_Concept
switch	I-General_Concept
logic	I-General_Concept
(	O
CVSL	O
)	O
and	O
pass	B-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
(	O
PTL	O
)	O
of	O
various	O
sorts	O
.	O
</s>
<s>
One	O
major	O
improvement	O
was	O
to	O
combine	O
CMOS	B-Device
inputs	O
and	O
TTL	B-General_Concept
drivers	O
to	O
form	O
of	O
a	O
new	O
type	O
of	O
logic	O
devices	O
called	O
BiCMOS	B-General_Concept
logic	I-General_Concept
,	O
of	O
which	O
the	O
LVT	O
and	O
ALVT	O
logic	B-General_Concept
families	I-General_Concept
are	O
the	O
most	O
important	O
.	O
</s>
<s>
The	O
BiCMOS	B-General_Concept
family	O
has	O
many	O
members	O
,	O
including	O
ABT	O
logic	O
,	O
ALB	O
logic	O
,	O
ALVT	O
logic	O
,	O
BCT	O
logic	O
and	O
LVT	O
logic	O
.	O
</s>
<s>
With	O
HC	O
and	O
HCT	O
logic	O
and	O
LS-TTL	O
logic	O
competing	O
in	O
the	O
market	O
it	O
became	O
clear	O
that	O
further	O
improvements	O
were	O
needed	O
to	O
create	O
the	O
ideal	O
logic	O
device	O
that	O
combined	O
high	O
speed	O
,	O
with	O
low	O
power	B-General_Concept
dissipation	I-General_Concept
and	O
compatibility	O
with	O
older	O
logic	B-General_Concept
families	I-General_Concept
.	O
</s>
<s>
A	O
whole	O
range	O
of	O
newer	O
families	O
has	O
emerged	O
that	O
use	O
CMOS	B-Device
technology	O
.	O
</s>
<s>
There	O
are	O
many	O
others	O
including	O
AC/ACT	O
logic	O
,	O
AHC/AHCT	O
logic	O
,	O
ALVC	O
logic	O
,	O
AUC	O
logic	O
,	O
AVC	O
logic	O
,	O
CBT	O
logic	O
,	O
CBTLV	O
logic	O
,	O
FCT	O
logic	O
and	O
LVC	O
logic	O
(	O
LVCMOS	B-General_Concept
)	O
.	O
</s>
<s>
The	O
integrated	B-General_Concept
injection	I-General_Concept
logic	I-General_Concept
(	O
IIL	O
or	O
I2L	B-General_Concept
)	O
uses	O
bipolar	O
transistors	B-Application
in	O
a	O
current-steering	O
arrangement	O
to	O
implement	O
logic	O
functions	O
.	O
</s>
<s>
The	O
following	O
logic	B-General_Concept
families	I-General_Concept
would	O
either	O
have	O
been	O
used	O
to	O
build	O
up	O
systems	O
from	O
functional	O
blocks	O
such	O
as	O
flip-flops	O
,	O
counters	O
,	O
and	O
gates	O
,	O
or	O
else	O
would	O
be	O
used	O
as	O
"	O
glue	O
"	O
logic	O
to	O
interconnect	O
very-large	O
scale	O
integration	O
devices	O
such	O
as	O
memory	O
and	O
processors	O
.	O
</s>
<s>
Not	O
shown	O
are	O
some	O
early	O
obscure	O
logic	B-General_Concept
families	I-General_Concept
from	O
the	O
early	O
1960s	O
such	O
as	O
DCTL	O
(	O
direct-coupled	O
transistor	B-Application
logic	O
)	O
,	O
which	O
did	O
not	O
become	O
widely	O
available	O
.	O
</s>
<s>
Family	O
Description	O
Propagation	O
delay	O
(	O
ns	O
)	O
Toggle	O
speed	O
(	O
MHz	O
)	O
Power	O
per	O
gate	O
@1	O
MHz	O
(	O
mW	O
)	O
Typical	O
supply	O
voltage	O
V	O
(	O
range	O
)	O
Introduction	O
year	O
Remarks	O
RTL	O
Resistor	O
–	O
transistor	B-Application
logic	O
500	O
4	O
10	O
3.3	O
1963	O
the	O
first	O
CPU	B-Device
built	O
from	O
integrated	O
circuits	O
(	O
the	O
Apollo	B-Application
Guidance	I-Application
Computer	I-Application
)	O
used	O
RTL	O
.	O
</s>
<s>
Several	O
techniques	O
and	O
design	O
styles	O
are	O
primarily	O
used	O
in	O
designing	O
large	O
single-chip	O
application-specific	O
integrated	O
circuits	O
(	O
ASIC	O
)	O
and	O
CPUs	B-Device
,	O
rather	O
than	O
generic	O
logic	B-General_Concept
families	I-General_Concept
intended	O
for	O
use	O
in	O
multi-chip	O
applications	O
.	O
</s>
<s>
clocked	B-General_Concept
dynamic	I-General_Concept
techniques	I-General_Concept
.	O
</s>
<s>
(	O
See	O
static	O
versus	O
dynamic	B-General_Concept
logic	I-General_Concept
for	O
some	O
discussion	O
on	O
the	O
advantages	O
and	O
disadvantages	O
of	O
each	O
category	O
)	O
.	O
</s>
