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參數(shù)資料
| 型號(hào)： | 74F181DC |
| 英文描述： | Fixed Point ALU |
| 中文描述： | ALU的不動(dòng)點(diǎn) |
| 文件頁數(shù)： | 2/8頁 |
| 文件大小： | 77K |
| 代理商： | 74F181DC |
www.fairchildsemi.com
2
7
Unit Loading/Fan Out
Functional Description
The 74F182 carry lookahead generator accepts up to four
pairs of Active LOW Carry Propagate (P
0
–
P
3
) and Carry
Generate (G
0
–
G
3
) signals and an Active HIGH Carry input
(C
n
) and provides anticipated Active HIGH carries (C
n
+
x
,
C
n
+
y
, C
n
+
z
) across four groups of binary adders. The
74F182 also has Active LOW Carry Propagate (P) and
Carry Generate (G) outputs which may be used for further
levels of lookahead. The logic equations provided at the
outputs are:
C
n
+
x
=
G
0
+
P
0
C
n
C
n
+
y
=
G
1
+
P
1
G
0
+
P
1
P
0
C
n
C
n
+
z
=
G
2
+
P
2
G
1
+
P
2
P
1
G
0
+
P
2
P
1
P
0
C
n
G
=
G
3
+
P
3
G
2
+
P
3
P
2
G
1
+
P
3
P
2
P
1
G
0
P
=
P
2
P
2
P
1
P
0
Also, the 74F182 can be used with binary ALUs in an
active LOW or active HIGH input operand mode. The con-
nections (Figure 1) to and from the ALU to the carry looka-
head generator are identical in both cases. Carries are
rippled between lookahead blocks. The critical speed path
follows the circled numbers. There are several possible
arrangements for the carry interconnects, but all achieve
about the same speed. A 28-bit ALU is formed by dropping
the last 74F181 or 74F381.
*ALUs may be either 74F181 or 74F381
FIGURE 1. 32-Bit ALU with Rippled Carry between 16-Bit Lookahead ALUs
Pin Names
Description
U.L.
Input I
IH
/I
IL
Output I
OH
/I
OL
20
μ
A/
1.2 mA
20
μ
A/
8.4 mA
20
μ
A/
9.6 mA
20
μ
A/
4.8 mA
20
μ
A/
4.8 mA
20
μ
A/
3.6 mA
20
μ
A/
2.4 mA
1 mA/20 mA
1 mA/20 mA
1 mA/20 mA
HIGH/LOW
1.0/2.0
1.0/14.0
1.0/16.0
1.0/8.0
1.0/8.0
1.0/6.0
1.0/4.0
50/33.3
50/33.3
50/33.3
C
n
G
0
, G
2
G
1
G
3
P
0
, P
1
P
2
P
3
C
n
+
x
C
n
+
z
G
P
Carry Input
Carry Generate Inputs (Active LOW)
Carry Generate Input (Active LOW)
Carry Generate Input (Active LOW)
Carry Propagate Inputs (Active LOW)
Carry Propagate Input (Active LOW)
Carry Propagate Input (Active LOW)
Carry Outputs
Carry Generate Output (Active LOW)
Carry Propagate Output (Active LOW)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 74F181FC | Fixed Point ALU |
| 74F181SCX | Fixed Point ALU |
| 74F181SDC | Fixed Point ALU |
| 74F182 | Look-ahead carry generator |
| 74F182 | Carry Lookahead Generator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 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 |
| 74F181SCX | 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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