74F182
器件描述：Look-ahead carry generator
器件厂商：PHILIPS [Philips Semiconductors]
文件大小：56.54KB，共6页
Sponsor by e络盟器件资料摘要：
Philips Semiconductors Product specification
74F182Look-ahead carry generator
21991 Apr 15 853–1161 02162
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
16
15
14
13
12
11
107
6
5
4
3
2
1
P
V
CC
Cn+x
Cn+y
G
Cn
P2
G2
G1
P1
P3
G0
P0
G3
98GND Cn+z
SF00725
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74F182 5.0ns 21mA
ORDERING INFORMATION
DESCRIPTION
ORDER CODE
COMMERCIAL RANGE
V
CC
= 5V ±10%, T
amb
= 0°C to +70°C
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 50µA/1.2mA
G0, G2 Carry generate inputs (active-Low) 2.5/14.0 50µA/8.4mA
G1 Carry generate input (active-Low) 2.5/16.0 50µA/9.6mA
G3 Carry generate input (active-Low) 2.5/8.0 50µA/4.8mA
P0, P1 Carry propagate inputs (active-Low) 2.5/8.0 50µA/4.8mA
P2 Carry propagate input (active-Low) 2.5/6.0 50µA/3.6mA
P3 Carry propagate input (active-Low) 2.5/4.0 50µA/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: 20µA in the High state and 0.6mA in the Low state.
74F182Look-ahead carry generator
21991 Apr 15 853–1161 02162
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
16
15
14
13
12
11
107
6
5
4
3
2
1
P
V
CC
Cn+x
Cn+y
G
Cn
P2
G2
G1
P1
P3
G0
P0
G3
98GND Cn+z
SF00725
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74F182 5.0ns 21mA
ORDERING INFORMATION
DESCRIPTION
ORDER CODE
COMMERCIAL RANGE
V
CC
= 5V ±10%, T
amb
= 0°C to +70°C
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 50µA/1.2mA
G0, G2 Carry generate inputs (active-Low) 2.5/14.0 50µA/8.4mA
G1 Carry generate input (active-Low) 2.5/16.0 50µA/9.6mA
G3 Carry generate input (active-Low) 2.5/8.0 50µA/4.8mA
P0, P1 Carry propagate inputs (active-Low) 2.5/8.0 50µA/4.8mA
P2 Carry propagate input (active-Low) 2.5/6.0 50µA/3.6mA
P3 Carry propagate input (active-Low) 2.5/4.0 50µA/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: 20µA in the High state and 0.6mA in the Low state.