Philips Semiconductors

Product specification

74F182

Look-ahead carry generator

2

1991 Apr 15

853–1161 02162

FEATURES

long word lengths

DESCRIPTION

The 74F182 is a high speed carry look-ahead generator. It accepts

up to four pairs of active-Low Carry Propagate (P0, P1, P2, P3) and

Carry Generate (G0, G1, G2, G3) signals and an active-High Carry

input (Cn) and provides anticipated active-High carries (Cn+x, Cn+y,

Cn+z) across four groups of binary adders. The 74F182 also has

active-Low Carry Propagate (P) Carry Generate (G) outputs which

may be used for further levels of look-ahead.

The logic equations provided at the outputs are:

Cn+x = G0+P0Cn

Cn+y = G1+P1G0+P1P0Cn

Cn+z = G2+P2G1+P2P1G0+P2P1P0Cn

G = G3+P3G2+P3P2G1+P3P2P1G0

P = P3P2P1P0

The 74F182 can also be used with binary ALUs in an active-Low or

active-High input operand mode. The connections to and from the

ALU to the carry look-ahead generator are identical in both cases.

PIN CONFIGURATION

16

15

14

13

12

11

10

7

6

5

4

3

2

1

P

Cn+x

Cn+y

G

Cn

P2

G2

G1

P1

P3

G0

P0

G3

9

8

GND

Cn+z

SF00725

TYPE

TYPICAL

PROPAGATION

DELAY

TYPICAL

SUPPLY CURRENT

(TOTAL)

74F182

5.0ns

21mA

ORDERING INFORMATION

DESCRIPTION

ORDER CODE

DESCRIPTION

COMMERCIAL RANGE

16-pin plastic DIP

N74F182N

16-pin plastic SO

N74F182D

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74FAST (U.L.) HIGH/LOW

LOAD VALUE HIGH/LOW

Cn

Carry input

2.5/2.0

50

µA/1.2mA

G0, G2

Carry generate inputs (active-Low)

2.5/14.0

50

µA/8.4mA

G1

Carry generate input (active-Low)

2.5/16.0

50

µA/9.6mA

G3

Carry generate input (active-Low)

2.5/8.0

50

µA/4.8mA

P0, P1

Carry propagate inputs (active-Low)

2.5/8.0

50

µA/4.8mA

P2

Carry propagate input (active-Low)

2.5/6.0

50

µA/3.6mA

P3

Carry propagate input (active-Low)

2.5/4.0

50

µA/2.4mA

Cn+x–Cn+z

Carry outputs

50/33

1.0mA/20mA

G

Carry generate output (active-Low)

50/33

1.0mA/20mA

P

Carry propagate output (active-Low)

50/33

1.0mA/20mA

NOTE:

One (1.0) FAST unit load is defined as: 20

µA in the High state and 0.6mA in the Low state.