<s>
Integrated	B-General_Concept
injection	I-General_Concept
logic	I-General_Concept
(	O
IIL	O
,	O
I2L	B-General_Concept
,	O
or	O
I2L	B-General_Concept
)	O
is	O
a	O
class	O
of	O
digital	O
circuits	O
built	O
with	O
multiple	O
collector	O
bipolar	O
junction	O
transistors	O
(	O
BJT	O
)	O
.	O
</s>
<s>
When	O
introduced	O
it	O
had	O
speed	O
comparable	O
to	O
TTL	B-General_Concept
yet	O
was	O
almost	O
as	O
low	O
power	O
as	O
CMOS	B-Device
,	O
making	O
it	O
ideal	O
for	O
use	O
in	O
VLSI	O
(	O
and	O
larger	O
)	O
integrated	O
circuits	O
.	O
</s>
<s>
The	O
gates	O
can	O
be	O
made	O
smaller	O
with	O
this	O
logic	O
family	O
than	O
with	O
CMOS	B-Device
because	O
complementary	O
transistors	O
are	O
not	O
needed	O
.	O
</s>
<s>
Although	O
the	O
logic	O
voltage	O
levels	O
are	O
very	O
close	O
(	O
High	O
:	O
0.7V	O
,	O
Low	O
:	O
0.2V	O
)	O
,	O
I2L	B-General_Concept
has	O
high	O
noise	O
immunity	O
because	O
it	O
operates	O
by	O
current	O
instead	O
of	O
voltage	O
.	O
</s>
<s>
I2L	B-General_Concept
was	O
developed	O
in	O
1971	O
by	O
Siegfried	O
K	O
.	O
Wiedmann	O
and	O
Horst	O
H	O
.	O
Berger	O
who	O
originally	O
called	O
it	O
merged-transistor	O
logic	O
(	O
MTL	O
)	O
.	O
</s>
<s>
A	O
disadvantage	O
of	O
this	O
logic	O
family	O
is	O
that	O
the	O
gates	O
draw	O
power	O
when	O
not	O
switching	O
unlike	O
with	O
CMOS	B-Device
.	O
</s>
<s>
The	O
I2L	B-General_Concept
inverter	O
gate	O
is	O
constructed	O
with	O
a	O
PNP	O
common	O
base	O
current	O
source	O
transistor	O
and	O
an	O
NPN	O
common	O
emitter	O
open	O
collector	O
inverter	O
transistor	O
(	O
i.e.	O
</s>
<s>
Thus	O
the	O
fan-out	B-General_Concept
of	O
an	O
output	O
used	O
in	O
such	O
a	O
way	O
is	O
one	O
.	O
</s>
<s>
In	O
a	O
discrete	O
implementation	O
of	O
an	O
I2L	B-General_Concept
circuit	O
,	O
bipolar	O
NPN	O
transistors	O
with	O
multiple	O
collectors	O
can	O
be	O
replaced	O
with	O
multiple	O
discrete	O
3-terminal	O
NPN	O
transistors	O
connected	O
in	O
parallel	O
having	O
their	O
bases	O
connected	O
together	O
and	O
their	O
emitters	O
connected	O
likewise	O
.	O
</s>
<s>
The	O
heart	O
of	O
an	O
I2L	B-General_Concept
circuit	O
is	O
the	O
common	O
emitter	O
open	O
collector	O
inverter	O
.	O
</s>
<s>
Due	O
to	O
internal	O
parasitic	O
capacitance	O
in	O
transistors	O
,	O
higher	O
currents	O
sourced	O
into	O
the	O
base	O
of	O
the	O
inverter	O
transistor	O
result	O
in	O
faster	O
switching	O
speeds	O
,	O
and	O
since	O
the	O
voltage	O
difference	O
between	O
high	O
and	O
low	O
logic	O
levels	O
is	O
smaller	O
for	O
I2L	B-General_Concept
than	O
other	O
bipolar	O
logic	O
families	O
(	O
around	O
0.5	O
volts	O
instead	O
of	O
around	O
3.3	O
or	O
5	O
volts	O
)	O
,	O
losses	O
due	O
to	O
charging	O
and	O
discharging	O
parasitic	O
capacitances	O
are	O
minimized	O
.	O
</s>
<s>
I2L	B-General_Concept
is	O
relatively	O
simple	O
to	O
construct	O
on	O
an	O
integrated	O
circuit	O
,	O
and	O
was	O
commonly	O
used	O
before	O
the	O
advent	O
of	O
CMOS	B-Device
logic	O
by	O
companies	O
such	O
as	O
Motorola	O
(	O
now	O
NXP	O
Semiconductors	O
)	O
and	O
Texas	O
Instruments	O
.	O
</s>
<s>
In	O
1975	O
,	O
Sinclair	O
Radionics	O
introduced	O
one	O
of	O
the	O
first	O
consumer-grade	O
digital	O
watches	O
,	O
the	O
Black	O
Watch	O
,	O
which	O
used	O
I2L	B-General_Concept
technology	O
.	O
</s>
<s>
In	O
1976	O
,	O
Texas	O
Instruments	O
introduced	O
SBP0400	B-General_Concept
CPU	O
which	O
used	O
I2L	B-General_Concept
technology	O
.	O
</s>
<s>
In	O
the	O
late	O
1970s	O
,	O
RCA	O
used	O
I²L	B-General_Concept
in	O
its	O
CA3162	O
ADC	O
3	O
digit	O
meter	O
integrated	O
circuit	O
.	O
</s>
<s>
In	O
1979	O
,	O
HP	O
introduced	O
a	O
frequency	O
measurement	O
instrument	O
based	O
on	O
a	O
HP-made	O
custom	O
LSI	O
chip	O
that	O
uses	O
integrated	B-General_Concept
injection	I-General_Concept
logic	I-General_Concept
(	O
I2L	B-General_Concept
)	O
for	O
low	O
power	O
consumption	O
and	O
high	O
density	O
,	O
enabling	O
portable	O
battery	O
operation	O
,	O
and	O
also	O
some	O
emitter	O
function	O
logic	O
(	O
EFL	O
)	O
circuits	O
where	O
high	O
speed	O
is	O
needed	O
in	O
its	O
HP	O
5315A/B	O
.	O
</s>
