<s>
Four-phase	B-General_Concept
logic	I-General_Concept
is	O
a	O
type	O
of	O
,	O
and	O
design	O
methodology	O
for	O
dynamic	B-General_Concept
logic	I-General_Concept
.	O
</s>
<s>
It	O
enabled	O
non-specialist	O
engineers	O
to	O
design	O
quite	O
complex	O
ICs	O
,	O
using	O
either	O
PMOS	B-Algorithm
or	O
NMOS	B-Algorithm
processes	O
.	O
</s>
<s>
R	O
.	O
K	O
.	O
"	O
Bob	O
"	O
Booher	O
,	O
an	O
engineer	O
at	O
Autonetics	O
,	O
invented	O
four-phase	B-General_Concept
logic	I-General_Concept
,	O
and	O
communicated	O
the	O
idea	O
to	O
Frank	O
Wanlass	O
at	O
Fairchild	O
Semiconductor	O
;	O
Wanlass	O
promoted	O
this	O
logic	O
form	O
at	O
General	O
Instrument	O
Microelectronics	O
Division	O
.	O
</s>
<s>
Booher	O
made	O
the	O
first	O
working	O
four-phase	O
chip	O
,	O
the	O
Autonetics	O
DDA	B-Device
integrator	I-Device
,	O
during	O
February	O
1966	O
;	O
he	O
later	O
designed	O
several	O
chips	O
for	O
and	O
built	O
the	O
Autonetics	O
D200	O
airborne	O
computer	O
using	O
this	O
technique	O
.	O
</s>
<s>
J	O
.	O
L	O
.	O
Seely	O
,	O
manager	O
of	O
MOS	O
Operations	O
at	O
General	O
Instrument	O
Microelectronics	O
Division	O
,	O
also	O
wrote	O
about	O
four-phase	B-General_Concept
logic	I-General_Concept
in	O
late	O
1967	O
.	O
</s>
<s>
Boysel	O
recalls	O
that	O
four-phase	O
dynamic	B-General_Concept
logic	I-General_Concept
allowed	O
him	O
to	O
achieve	O
10X	O
the	O
packing	O
density	O
,	O
10X	O
the	O
speed	O
,	O
and	O
1/10	O
the	O
power	O
,	O
compared	O
to	O
other	O
MOS	O
techniques	O
being	O
used	O
at	O
the	O
time	O
(	O
metal-gate	B-Algorithm
saturated-load	O
PMOS	B-Algorithm
logic	I-Algorithm
)	O
,	O
using	O
the	O
first-generation	O
MOS	O
process	O
at	O
Fairchild	O
.	O
</s>
<s>
An	O
example	O
2-input	O
NAND	O
1	O
gate	O
and	O
an	O
inverter	O
3	O
gate	O
,	O
together	O
with	O
their	O
clock	O
phases	O
(	O
the	O
example	O
uses	O
NMOS	B-Algorithm
transistors	O
)	O
,	O
are	O
shown	O
below	O
:	O
</s>
<s>
Four-phase	B-General_Concept
logic	I-General_Concept
works	O
well	O
;	O
in	O
particular	O
there	O
are	O
no	O
race	O
hazards	O
because	O
every	O
combinational	O
logic	O
gate	O
includes	O
a	O
register	O
.	O
</s>
<s>
static	B-General_Concept
logic	I-General_Concept
)	O
,	O
many	O
designs	O
can	O
use	O
minimum-size	O
transistors	O
.	O
</s>
<s>
The	O
first	O
electronic	O
calculator	O
to	O
be	O
built	O
with	O
large	O
scale	O
integrated	O
circuits	O
(	O
LSI	O
)	O
,	O
the	O
Sharp	B-Device
QT-8D	I-Device
from	O
1969	O
,	O
used	O
4-phase	O
logic	O
which	O
was	O
fabricated	O
by	O
Rockwell	O
International	O
because	O
Japan	O
did	O
not	O
yet	O
have	O
the	O
LSI	O
technology	O
to	O
do	O
it	O
domestically	O
.	O
</s>
<s>
4-phase	O
logic	O
was	O
also	O
considered	O
for	O
use	O
in	O
the	O
Intel	B-General_Concept
4004	I-General_Concept
,	O
but	O
only	O
Rockwell	O
had	O
the	O
design	O
tools	O
and	O
expertise	O
to	O
do	O
large	O
scale	O
4-phase	O
ICs	O
at	O
that	O
time	O
so	O
Intel	O
settled	O
on	O
2-phase	O
dynamic	B-General_Concept
logic	I-General_Concept
instead	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
CMOS	B-Device
,	O
the	O
precharge	O
transistor	O
could	O
be	O
changed	O
to	O
be	O
the	O
complement	O
of	O
the	O
logic	O
transistor	O
type	O
,	O
which	O
allows	O
the	O
gate	O
's	O
output	O
to	O
charge	O
quickly	O
all	O
the	O
way	O
up	O
to	O
the	O
high	O
level	O
of	O
the	O
clock	O
line	O
,	O
thus	O
improving	O
the	O
speed	O
,	O
signal	O
swing	O
,	O
power	O
consumption	O
,	O
and	O
noise	O
margin	O
.	O
</s>
<s>
This	O
technique	O
is	O
used	O
in	O
domino	B-General_Concept
logic	I-General_Concept
.	O
</s>
