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參數(shù)資料
| 型號： | 74F189SCX |
| 英文描述： | x4 SRAM |
| 中文描述： | x4的SRAM |
| 文件頁數(shù)： | 2/8頁 |
| 文件大?。?/td> | 77K |
| 代理商： | 74F189SCX |
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 |
|---|---|
| 74F189SJX | SRAM|16X4|F-TTL|SOP|16PIN|PLASTIC |
| 74F181DC | Fixed Point ALU |
| 74F181FC | Fixed Point ALU |
| 74F181SCX | Fixed Point ALU |
| 74F181SDC | Fixed Point ALU |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 74F189SJ | 功能描述:RAM其它 64-Bit Ran Acces Mem RoHS:否 制造商:Freescale Semiconductor 封裝:Tray |
| 74F189SJX | 功能描述:RAM其它 RoHS:否 制造商:Freescale Semiconductor 封裝:Tray |
| 74F190 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Up/Down Decade Counter with Preset and Ripple Clock |
| 74F190 WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| 74F190DC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Synchronous Up/Down Counter |
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