HD74AC182
Carry Lookahead Generator
REJ03D0258–0200Z
(Previous ADE-205-378 (Z))
Rev.2.00
Jul.16.2004
Description
The HD74AC182 is a high-speed carry lookahead generator. It is generally used with the HD74AC181 or HD74AC381
4-bit arithmetic logic unit to provide high-speed lookahead over word lengths of more than four bits.
Features
•
Outputs Source/Sink 24 mA
•
Ordering Information
Part Name
HD74AC182FPEL
HD74AC182RPEL
Package Type
SOP-16 pin (JEITA)
Package Code Package Abbreviation Taping Abbreviation (Quantity)
FP-16DAV
FP
RP
EL (2,000 pcs/reel)
EL (2,500 pcs/reel)
SOP-16 pin (JEDEC) FP-16DNV
Notes: 1. Please consult the sales office for the above package availability.
2. The packages with lead-free pins are distinguished from the conventional products by adding V at the end of
the package code.
Pin Arrangement
G
1
1
P
1
2
G
0
3
P
0
4
G
3
5
P
3
6
P
7
GND 8
(Top view)
16 V
CC
15
P
2
14
G
2
13 C
n
12 C
n+X
11 C
n+y
10
G
9 C
n+z
Rev.2.00, Jul.16.2004, page 1 of 6
HD74AC182
Logic Symbol
P
0
G
0
C
n
P
1
G
1
P
2
G
2
P
3
G
3
G
P
C
n+x
C
n+y
C
n+z
Pin Names
Cn
G
0
,
G
2
G
1
G
3
P
0
,
P
1
P
2
P
3
C
n + x
to C
n + z
G
P
Carry Input
Carry Generate Inputs (Active Low)
Carry Generate Input (Active Low)
Carry Generate Input (Active Low)
Carry Propagate Inputs (Active Low)
Carry Propagate Input (Active Low)
Carry Propagate Input (Active Low)
Carry Outputs
Carry Generate Output (Active Low)
Carry Propagate Output (Active Low)
Logic Diagram
C
n
G
0
P
0
G
1
P
1
G
2
P
2
G
3
P
3
C
n+x
C
n+y
C
n+z
G
P
Please note that this diagram is provided only for the understanding of logic operations and should not be
used to estimate propagation delays.
Functional Description
The HD74AC182/HD74ACT182 carry lookahead generator accepts up to four pairs of Active Low Carry Propagate (P
0
to
P
3
) and Carry Generate (G
0
to
G
3
) signals and an Active High Carry input (Cn) and provides anticipated Active High
carries (C
n + x
, C
n + y
, C
n + z
) across four groups of binary adders. The HD74AC182/HD74ACT182 also has Active Low
Carry Propagate (P) and Carry Generate (G) outputs which may be used for further level of lookahead. The logic
equations provided at the outputs are:
Rev.2.00, Jul.16.2004, page 2 of 6
HD74AC182
C
n + x
= G
0
+ P
0
C
n
C
n + y
= G
1
+ P
1
G
0
+ P
1
P
0
C
n
C
n + z
= G
2
+ P
2
G
1
+ P
2
P
1
G
0
+ P
2
P
1
P
0
C
n
G
= G
3
+ P
3
G
2
+ P
3
P
2
G
1
+ P
3
P
2
P
1
G
0
P
= P
3
P
2
P
1
P
0
Also, the HD74AC182/HD74ACT182 can be used with binary ALUs in an active Low or active High input operand
mode. The connections (Figure a) to and from the ALU to the carry lookahead generator are identical in both cases.
Carries are rippled between lookahead blocks. The critical speed path follows the circled numbers. There are several
possible arrangements for the carry interconnects, but all achieve about the same speed. A 28-bit ALU is formed by
dropping the last HD74AC182/HD74ACT182.
Truth Table
Inputs
C
n
X
L
X
H
X
X
L
X
X
H
X
X
X
L
X
X
X
H
H
H
L
X
X
H
H
X
L
X
X
X
H
H
X
X
L
X
X
X
X
H
X
X
X
L
H
X
X
X
L
H :
L :
X :
High Voltage Level
Low Voltage Level
Immaterial
G
0
H
X
X
L
X
H
X
X
X
L
X
X
H
X
X
X
X
L
H
H
H
L
X
X
X
H
H
H
X
L
X
X
X
X
H
H
X
X
L
X
H
X
X
X
L
L
X
H
X
X
X
X
L
L
X
X
H
X
X
X
X
L
X
H
X
X
L
H
H
H
H
L
X
X
X
X
H
H
H
X
L
X
X
H
X
X
X
X
L
L
L
X
H
X
X
X
X
L
L
X
X
H
X
L
H
H
H
H
L
X
X
X
H
X
X
X
X
L
L
L
X
X
X
H
L
P
0
G
1
P
1
G
2
P
2
G
3
P
3
L
L
H
H
L
L
L
H
H
H
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
L
C
n + x
C
n + y
Outputs
C
n + z
G
P
Rev.2.00, Jul.16.2004, page 3 of 6
HD74AC182
Absolute Maximum Ratings
Item
Supply voltage
DC input diode current
DC input voltage
DC output diode current
DC output voltage
DC output source or sink current
DC V
CC
or ground current per output pin
Storage temperature
Symbol
V
CC
I
IK
V
I
I
OK
V
O
I
O
I
CC
, I
GND
Tstg
Ratings
–0.5 to 7
–20
20
–0.5 to Vcc+0.5
–50
50
–0.5 to Vcc+0.5
±50
±50
–65 to +150
Unit
V
mA
mA
V
mA
mA
V
mA
mA
°C
Condition
V
I
= –0.5V
V
I
= Vcc+0.5V
V
O
= –0.5V
V
O
= Vcc+0.5V
Recommended Operating Conditions
Item
Supply voltage
Input and output voltage
Operating temperature
Input rise and fall time
(except Schmitt inputs)
V
IN
30% to 70% V
CC
Symbol
V
CC
V
I
, V
O
Ta
tr, tf
Ratings
2 to 6
0 to V
CC
–40 to +85
8
V
V
°C
ns/V
V
CC
= 3.0V
V
CC
= 4.5 V
V
CC
= 5.5 V
Unit
Condition
DC Characteristics
Item
Sym-
bol
V
IH
Vcc
(V)
3.0
4.5
5.5
V
IL
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
V
OL
5.5
3.0
4.5
5.5
3.0
4.5
Input leakage
current
Dynamic output
current*
I
IN
I
OLD
I
OHD
5.5
5.5
5.5
5.5
min.
2.1
3.15
3.85
—
—
—
2.9
4.4
5.4
2.58
3.94
4.94
—
—
—
—
—
—
—
—
—
Ta = 25°C
°
typ.
1.5
2.25
2.75
1.50
2.25
2.75
2.99
4.49
5.49
—
—
—
0.002
0.001
0.001
—
—
—
—
—
—
max.
—
—
—
0.9
1.35
1.65
—
—
—
—
—
—
0.1
0.1
0.1
0.32
0.32
0.32
±0.1
—
—
Ta = –40 to
+85°C
°
min.
2.1
3.15
3.85
—
—
—
2.9
4.4
5.4
2.48
3.80
4.80
—
—
—
—
—
—
—
86
–75
—
max.
—
—
—
0.9
1.35
1.65
—
—
—
—
—
—
0.1
0.1
0.1
0.37
0.37
0.37
±1.0
—
—
80
µA
mA
mA
µA
V
V
OUT
= 0.1 V or V
CC
–0.1 V
Unit
Condition
Input Voltage
V
V
OUT
= 0.1 V or V
CC
–0.1 V
Output voltage
V
OH
V
IN
= V
IL
or V
IH
I
OUT
= –50
µA
V
IN
= V
IL
or V
IH
I
OH
= –12 mA
I
OH
= –24 mA
I
OH
= –24 mA
V
IN
= V
IL
or V
IH
I
OUT
= 50
µA
V
IN
= V
IL
or V
IH
I
OL
= 12 mA
I
OL
= 24 mA
I
OL
= 24 mA
V
IN
= V
CC
or GND
V
OLD
= 1.1 V
V
OHD
= 3.85 V
V
IN
= V
CC
or ground
Quiescent supply
5.5
—
—
8.0
I
CC
current
*Maximum
test duration 2.0 ms, one output loaded at a time.
Rev.2.00, Jul.16.2004, page 4 of 6
HD74AC182
AC Characteristics
Ta = +25°C
C
L
= 50 pF
Item
Propagation delay
P
n
to P
Propagation delay
P
n
to P
Propagation delay
C
n
to C
n + x, y, z
Propagation delay
C
n
to C
n + x, y, z
Propagation delay
P
n
or G
n
to C
n + x, y, z
Propagation delay
P
n
or G
n
to C
n + x, y, z
Note:
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
V
CC
(V)*
1
Min
3.3
1.0
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Typ
8.0
5.5
8.0
5.5
9.5
7.5
9.0
7.0
10.5
8.0
11.5
9.0
Max
10.5
8.0
10.5
8.0
12.0
10.0
12.0
10.0
13.0
10.5
14.0
11.5
Ta = –40°C to +85°C
C
L
= 50 pF
Min
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Max
11.5
9.0
11.5
9.0
13.0
11.0
13.0
11.0
14.0
11.5
15.5
12.5
Unit
ns
ns
ns
ns
ns
ns
1. Voltage Range 3.3 is 3.3 V ± 0.3 V
Voltage Range 5.0 is 5.0 V ± 0.5 V
Capacitance
Item
Input capacitance
Power dissipation capacitance
Symbol
C
IN
C
PD
4.5
50.0
Typ
pF
pF
Unit
V
CC
= 5.5 V
V
CC
= 5.0 V
Condition
Rev.2.00, Jul.16.2004, page 5 of 6
Analog electronics
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