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參數(shù)資料
| 型號： | DM74LS181 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | 4-Bit Arithmetic Logic Unit |
| 中文描述： | 4位算術(shù)邏輯單元 |
| 文件頁數(shù)： | 2/7頁 |
| 文件大?。?/td> | 74K |
| 代理商： | DM74LS181 |
www.fairchildsemi.com
2
D
Functional Description
The DM74LS181 is a 4-bit high speed parallel Arithmetic
Logic Unit (ALU). Controlled by the four Function Select
inputs (S0–S3) and the Mode Control input (M), it can per-
form all the 16 possible logic operations or 16 different
arithmetic operations on active HIGH or active LOW oper-
ands. 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 per-
forms arithmetic operations on the two 4-bit words. The
device incorporates full internal carry lookahead and pro-
vides for either ripple carry between devices using the C
n
+
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 indi-
cates that F is 16 or more. In the SUBTRACT mode, P indi-
cates 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 requirements are not stringent, it can be used in a
simple ripple carry mode by connecting the Carry output
(C
n
+
4
) signal to the Carry input (C
n
) of the next unit. For
high speed operation the device is used in conjunction with
the 9342 or 93S42 carry lookahead circuit. One carry loo-
kahead package is required for each group of four
DM74LS181 devices. Carry lookahead can be provided at
various levels and offers high speed capability over
extremely long word lengths.
The A
=
B output from the device goes HIGH when all four
F outputs are HIGH and can be used to indicate logic
equivalence over four bits when the unit is in the subtract
mode. The A
=
B output is open-collector and can be wired-
AND with other A
=
B outputs to give a comparison for
more than four bits. The A
=
B signal can also be used with
the C
n
+
4
signal to indicate A
>
B and A
<
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.
Because subtraction is actually performed by complemen-
tary 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 indi-
cated, this device 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 operations that are performed to the oper-
ands labeled inside the logic symbol.
Function Table
Note 1:
Each bit is shifted to the next most significant position.
Note 2:
Arithmetic operations expressed in 2s complement notation.
Mode Select
Inputs
Active LOW Operands
& F
n
Outputs
Logic
Active HIGH Operands
& F
n
Outputs
Logic
Arithmetic
(Note 2)
(M
=
L) (C
n
=
L)
Arithmetic
(Note 2)
(M
=
L) (C
n
=
H)
S3
S2
S1
S0
(M
=
H)
(M
=
H)
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
A
AB
A
+
B
Logic 1
A
+
B
B
A
⊕
B
A
+
B
A B
A
⊕
B
B
A
+
B
Logic 0
AB
AB
A
A minus 1
AB minus 1
AB minus 1
minus 1
A plus (A
+
B)
AB plus (A
+
B)
A minus B minus 1
A
+
B
A plus (A
+
B)
A plus B
AB plus (A
+
B)
A
+
B
A plus A (Note 1)
AB plus A
AB minus A
A
A
A
+
B
A B
Logic 0
AB
B
A
⊕
B
AB
A
+
B
A
⊕
B
B
AB
Logic 1
A
+
B
A
+
B
A
A
A
+
B
A
+
B
minus 1
A plus AB
(A
+
B) plus AB
A minus B minus 1
AB minus 1
A plus AB
A plus B
(A
+
B) plus AB
AB minus 1
A plus A (Note 1)
(A
+
B) plus A
(A
+
B) plus A
A minus 1
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DM74LS181N | 16-Bit D Flip-Flop with 3-STATE Outputs |
| DM74LS191M | Synchronous 4-Bit Up/Down Counter with Mode Control |
| DM74LS191 | Synchronous 4-Bit Up/Down Binary Counter with Mode Control(帶模式控制的同步4位二進制加/減計數(shù)器) |
| DM74LS191N | Synchronous 4-Bit Up/Down Counter with Mode Control |
| DM74LS191MX | Synchronous Up/Down Counter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DM74LS181N | 功能描述:算數(shù)邏輯單元 - ALU 4-Bit Arithmetic Log 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 |
| DM74LS191 WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| DM74LS191M | 功能描述:計數(shù)器 IC Syn 4-Bit Counter RoHS:否 制造商:NXP Semiconductors 計數(shù)器類型:Binary Counters 邏輯系列:74LV 位數(shù):10 計數(shù)法: 計數(shù)順序: 工作電源電壓:1 V to 5.5 V 工作溫度范圍:- 40 C to + 125 C 封裝 / 箱體:SOT-109 封裝:Reel |
| DM74LS191MX | 功能描述:計數(shù)器 IC Syn 4-Bit Counter RoHS:否 制造商:NXP Semiconductors 計數(shù)器類型:Binary Counters 邏輯系列:74LV 位數(shù):10 計數(shù)法: 計數(shù)順序: 工作電源電壓:1 V to 5.5 V 工作溫度范圍:- 40 C to + 125 C 封裝 / 箱體:SOT-109 封裝:Reel |
| DM74LS191N | 功能描述:計數(shù)器 IC Syn 4-Bit Counter RoHS:否 制造商:NXP Semiconductors 計數(shù)器類型:Binary Counters 邏輯系列:74LV 位數(shù):10 計數(shù)法: 計數(shù)順序: 工作電源電壓:1 V to 5.5 V 工作溫度范圍:- 40 C to + 125 C 封裝 / 箱體:SOT-109 封裝:Reel |
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