74F182 Datasheet, PDF (1/6 Pages) NXP Semiconductors – Look-ahead carry generator

Philips Semiconductors
Look-ahead carry generator
Product specification
74F182
FEATURES
• Provides carry look-ahead across a group of four ALUs
• Multi-level look-ahead for high speed arithmetic operation over
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
G1 1
P1 2
G0 3
P0 4
G3 5
P3 6
P7
GND 8
16 V_CC
15 P2
14 G2
13 Cn
12 Cn+x
11 Cn+y
10 G
9 Cn+z
SF00725
TYPE
74F182
TYPICAL
PROPAGATION
DELAY
5.0ns
TYPICAL
SUPPLY CURRENT
(TOTAL)
21mA
ORDERING INFORMATION
DESCRIPTION
16-pin plastic DIP
ORDER CODE
COMMERCIAL RANGE
V_CC = 5V ±10%, T_amb = 0°C to +70°C
N74F182N
16-pin plastic SO
N74F182D
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74FAST (U.L.) HIGH/LOW
Cn
Carry input
2.5/2.0
G0, G2
Carry generate inputs (active-Low)
2.5/14.0
G1
Carry generate input (active-Low)
2.5/16.0
G3
Carry generate input (active-Low)
2.5/8.0
P0, P1
Carry propagate inputs (active-Low)
2.5/8.0
P2
Carry propagate input (active-Low)
2.5/6.0
P3
Carry propagate input (active-Low)
2.5/4.0
Cn+x–Cn+z
Carry outputs
50/33
G
Carry generate output (active-Low)
50/33
P
Carry propagate output (active-Low)
50/33
NOTE:
One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state.
LOAD VALUE HIGH/LOW
50µA/1.2mA
50µA/8.4mA
50µA/9.6mA
50µA/4.8mA
50µA/4.8mA
50µA/3.6mA
50µA/2.4mA
1.0mA/20mA
1.0mA/20mA
1.0mA/20mA
1991 Apr 15
2
853–1161 02162