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HD74AC182
Rev.2.00, Jul.16.2004, page 2 of 6
Logic Symbol
C
n
G
P
P
0
C
n+x
C
n+y
C
n+z
G
0
P
1
G
1
P
2
G
2
P
3
G
3
Pin Names
Cn Carry Input
G
0
, G
2
Carry Generate Inputs (Active Low)
G
1
Carry Generate Input (Active Low)
G
3
Carry Generate Input (Active Low)
P
0
, P
1
Carry Propagate Inputs (Active Low)
P
2
Carry Propagate Input (Active Low)
P
3
Carry Propagate Input (Active Low)
C
n + x
to C
n + z
Carry Outputs
G Carry Generate Output (Active Low)
P Carry Propagate Output (Active Low)
Logic Diagram
Cn
Cn+x Cn+y Cn+z
G0 P0 G1
GP
P1 G2 P2 G3 P3
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: