ITT - Index of

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I mm
ITT54182, ITT74182
-L.L ____ _
SEMICONDUCTORS
LOOK-AHEAD CARRY GENERATOR
MSI LOOK-AHEAD CARRY GENERATOR
The ITT54182. ITI74182 is a high-speed. lookahead
carry generator capable of anticipating a
carry across four binary adders or group of adders.
It is cascadable to perform full look-ahead across
n-bit adders. with only 13 nanosecond delay for
each level of look-ahead. Carry. generate-carry. and
propagate-carry functions are provided as enumerated
in the pin designation table above.
DUAL-IN-LiNE PACKAGE
AND FLAT PACKAGE
PIN CONFIGURATION
(TOP VIEW)t
The ITT54182 or ITT74182. when used in conjunction
with the ITT54181 or ITT74181 arithmetic
logic unit (ALU) provides full high-speed carry lookahead
capability for up to n-bit words. Each ITT-
54182/1TT74182 generates the look-ahead (anticipated
carry) across a group o'f four ALUs and. in
addition. other carry look-ahead circuits may be
employed to anticipate carry across sections of four
look-ahead packages up to n-bits.
Carry inputs and outputs of the ITT-
54181/1TT74181 are, in their true form. and the
carry propagate (P) and carry generate (G) are in
negated form; therefore. the carry (input. outputs.
generate. and propagate) functions of the lookahead
circuit are implemented in the compatible
forms. Reinterpretations of carry functions at the
ITT54181/1TT74181 are also applicable and compatible
with the look-ahead package. Logic equations
are:
Cn + x = GO + POCn
Cn + y =G 1 +P1GO+P1POCn
Cn + z = G2 + P2 G1 + P2 P1GO + P2 P1POCn
G = G3 + P3 G2 + P3 P2 G 1+ P3 P2 P1 GO
P = P3 P2 P1 Po
Inputs of the ITT54182/1TT74182 are diodeclamped
to minimize transmission-line effects. and
Darlington outputs are employed to improve turnoff
times and reduce propagation delay times. Typically.
the average carry time is 13 nanoseconds.
and power dissipation is typically 180 milliwatts or
11 milliwatts per gate. The ITT54182 is characterized
for operation over the full military temperature
range of -55°C to 125°C; the ITT74182 is characterized
for operation from 0° C to 70° C.
LOGIC: SEE DESCRIPTION
tplN ASSIGNMENTS FOR THESE CIRCUITS
ALL PACKAGES.
ARE THE SAME FOR
absolute maximum ratings over operating freeair
temperature range (unless otherwise noted)
Supply voltage V CC (see Note 1) ................ ; ........... 7V
Input voltage (see Note 1) .................................... 5.5V
Interemitter voltage (see Note 2) ........................ 5.5V
Operating free-air temperature range:
ITT54182 ....................................... - 55°C to 125°C
ITT74182 ................................................ O°Cto 70°C
Storage temperature range ........... -65°C to 150°C
Notes: 1. Voltage values are with respect to network
ground terminal.
2. This is the voltage between two emitters of
a multiple-emitter transistor. For this circuit.
this rating applies to each G input in conjunction
with any other G input or in conjunction
with any P input.
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