74F381PC Fairchild Semiconductor, 74F381PC Datasheet - Page 2

• Manufacturer Part Number: 74F381PC
• Description: IC ARITHMETIC LOGIC 4BIT 20-DIP
• Manufacturer: Fairchild Semiconductor
• Series: 74Fr

Specifications of 74F381PC

• Logic Type: Arithmetic Logic Unit
• Supply Voltage: 4.5 V ~ 5.5 V
• Number Of Bits: 4
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 74F381

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Unit Loading/Fan Out
Functional Description
Signals applied to the Select inputs S
mode of operation, as indicated in the Function Select
Table. An extensive listing of input and output levels is
shown in the Truth Table. The circuit performs the arith-
metic functions for either active HIGH or active LOW oper-
ands, with output levels in the same convention. In the
Subtract operating modes, it is necessary to force a carry
(HIGH for active HIGH operands, LOW for active LOW
operands) into the C
The Carry Generate (G) and Carry Propagate (P) outputs
supply input signals to the 74F182 carry lookahead gener-
ator for expansion to longer word length, as shown in Fig-
ure 2. Note that an 74F382 ALU is used for the most
significant package. Typical delays for Figure 2 are given in
Figure 1.
Pin Names
A
B
S
C
G
P
F
0
0
0
0
n
n
–F
–A
–B
–S
input of the least significant package.
3
3
3
2
A
P
C
C
Total Delay
FIGURE 2. 16-Bit Lookahead Carry ALU Expansion
i
i
n
n
A Operand Inputs
B Operand Inputs
Function Select Inputs
Carry Input
Carry Generate Output (Active LOW)
Carry Propagate Output (Active LOW)
Function Outputs
or B
to C
to F
or C
Path Segment
0
i
n
–S
n
to P
2
FIGURE 1. 16-Bit Delay Tabulation
('F182)
4, OVR
determine the
Description
2
Toward
21.5 ns
7.2 ns
6.2 ns
8.1 ns
Function Select Table
H
L
—
F
LOW Voltage Level
HIGH Voltage Level
S
H
H
H
H
L
L
L
L
0
C
HIGH/LOW
n
50/33.3
50/33.3
50/33.3
Output
21.4 ns
1.0/3.0
1.0/3.0
1.0/1.0
1.0/4.0
7.2 ns
6.2 ns
8.0 ns
U.L.
—
4, OVR
Select
S
H
H
H
H
L
L
L
L
1
Output I
20 A/ 1.8 mA
20 A/ 1.8 mA
20 A/ 0.6 mA
20 A/ 2.4 mA
S
H
H
H
H
Input I
L
L
L
L
1 mA/20 mA
1 mA/20 mA
1 mA/20 mA
2
Clear
B Minus A
A Minus B
A Plus B
A B
A
AB
Preset
IH
OH
Operation
/I
/I
IL
B
OL