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參數(shù)資料
| 型號(hào)： | 74F181 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | 4-Bit Arithmetic Logic Unit(4位算術(shù)邏輯單元) |
| 中文描述： | 4位算術(shù)邏輯單元（4位算術(shù)邏輯單元） |
| 文件頁(yè)數(shù)： | 2/10頁(yè) |
| 文件大?。?/td> | 218K |
| 代理商： | 74F181 |
Logic Symbols
Active-HIGH Operands
TL/F/9491–3
Active-LOW Operands
TL/F/9491–4
IEEE/IEC
TL/F/9491–10
Unit Loading/Fan Out
54F/74F
Pin Names
Description
U.L.
Input I
IH
/I
IL
HIGH/LOW Output I
OH
/I
OL
A
0
–A
3
B
0
–B
3
S
0
–S
3
M
C
n
F
0
–F
3
A
e
B
G
P
C
n
a
4
A Operand Inputs (Active LOW)
B Operand Inputs (Active LOW)
Function Select Inputs
Mode Control Input
Carry Input
Function Outputs (Active LOW)
Comparator Output
Carry Generate Output (Active LOW)
Carry Propagate Output (Active LOW)
Carry Output
1.0/3.0
1.0/3.0
1.0/4.0
1.0/1.0
1.0/5.0
50/33.3
OC
*
/33.3
50/33.3
50/33.3
50/33.3
20
m
A/
b
1.8 mA
20
m
A/
b
1.8 mA
20
m
A/
b
2.4 mA
20
m
A/
b
0.6 mA
20
m
A/
b
3.0 mA
b
1 mA/20 mA
*
/20 mA
b
1 mA/20 mA
b
1 mA/20 mA
b
1 mA/20 mA
*
OC-Open Collector
Functional Description
The ’F181 is a 4-bit high-speed parallel Arithmetic Logic
Unit (ALU). Controlled by the four Function Select inputs
(S
0
–S
3
) and the Mode Control input (M), it can perform all
the 16 possible logic operations or 16 different arithmetic
operations on Active HIGH or Active LOW operands. The
Function Table lists these operations.
When the Mode Control input (M) is HIGH, all internal car-
ries are inhibited and the device performs logic operations
on the individual bits as listed. When the Mode Control input
is LOW, the carries are enabled and the device performs
arithmetic operations on the two 4-bit words. The device
incorporates full internal carry lookahead and provides for
either ripple carry between devices using the C
n
a
4
output,
or for carry lookahead between packages using the signals
P (Carry Propagate) and G (Carry Generate). In the Add
mode, P indicates that F is 15 or more, while G indicates
that F is 16 or more. In the Subtract mode P indicates that F
is zero or less, while G indicates that F is less than zero. P
and G are not affected by carry in. When speed require-
ments are not stringent, the ’F181 can be used in a simple
Ripple Carry mode by connecting the Carry output (C
n
a
4)
signal to the Carry input (C
n
) of the next unit. For high speed
operation the device is used in conjunction with a carry look-
ahead circuit. One carry lookahead package is required for
each group of four ’F181 devices. Carry lookahead can be
provided at various levels and offers high speed capability
over extremely long word lengths.
The A
e
B output from the device goes HIGH when all four F
outputs are HIGH and can be used to indicate logic equiva-
lence over four bits when the unit is in the Subtract mode.
The A
e
B output is open collector and can be wired AND
with other A
e
B outputs to give a comparison for more than
four bits. The A
e
B signal can also be used with the C
n
a
4
signal to indicate A
l
B and A
k
B.
The Function Table lists the arithmetic operations that are
performed without a carry in. An incoming carry adds a one
to each operation. Thus, select code LHHL generates A
minus B minus 1 (2s complement notation) without a carry
in and generates A minus B when a carry is applied. Be-
cause subtraction is actually performed by complementary
addition (1s complement), a carry out means borrow; thus a
carry is generated when there is no underflow and no carry
is generated when there is underflow. As indicated, this de-
vice can be used with either active LOW inputs producing
active LOW outputs or with active HIGH inputs producing
active HIGH outputs. For either case the table lists the oper-
ations that are performed to the operands labeled inside the
logic symbol.
2
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 74F181DC | 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:Fixed Point ALU |
| 74F181FC | 制造商:Texas Instruments 功能描述: |
| 74F181N | 制造商:NXP Semiconductors 功能描述: |
| 74F181PC | 功能描述:算數(shù)邏輯單元 - ALU 4-Bit Arith Log Unit RoHS:否 制造商:ON Semiconductor 高電平輸出電流: 低電平輸出電流: 傳播延遲時(shí)間: 電源電壓-最大:18 V 電源電壓-最小:3 V 封裝 / 箱體:SOIC-16 Wide 最大工作溫度:+ 125 C 封裝:Reel |
| 74F181SC | 功能描述:算數(shù)邏輯單元 - ALU 4-Bit Arith Log Unit RoHS:否 制造商:ON Semiconductor 高電平輸出電流: 低電平輸出電流: 傳播延遲時(shí)間: 電源電壓-最大:18 V 電源電壓-最小:3 V 封裝 / 箱體:SOIC-16 Wide 最大工作溫度:+ 125 C 封裝:Reel |
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