- 您現(xiàn)在的位置：買賣IC網 > PDF目錄360432 > 74F257ASJX 2-Input Digital Multiplexer PDF資料下載
參數資料
| 型號： | 74F257ASJX |
| 英文描述： | 2-Input Digital Multiplexer |
| 中文描述： | 2，輸入數字復接器 |
| 文件頁數： | 2/7頁 |
| 文件大小： | 76K |
| 代理商： | 74F257ASJX |
www.fairchildsemi.com
2
7
Unit Loading/Fan Out
Truth Table
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Z
=
High Impedance
Functional Description
The 74F257A is a quad 2-input multiplexer with 3-STATE
outputs. It selects four bits of data from two sources under
control of a Common Data Select input. When the Select
input is LOW, the I
0x
inputs are selected and when Select
is HIGH, the I
1x
inputs are selected. The data on the
selected inputs appears at the outputs in true (non-
inverted) form. The device is the logic implementation of a
4-pole, 2-position switch where the position of the switch is
determined by the logic levels supplied to the Select input.
The logic equation for the outputs is shown below:
Z
n
=
OE
(I
n
S
+
I
on
S)
When the Output Enable input (OE) is HIGH, the outputs
are forced to a high impedance OFF state. If the outputs
are tied together, all but one device must be in the high
impedance state to avoid high currents that would exceed
the maximum ratings. Designers should ensure the Output
Enable signals to 3-STATE devices whose outputs are tied
together are designed so there is no overlap.
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
Pin Names
Description
U.L.
Input I
/I
IL
Output I
OH
/I
OL
20
μ
A/
0.6 mA
20
μ
A/
0.6 mA
20
μ
A/
0.6 mA
20
μ
A/
0.6 mA
3 mA/24 mA (20 mA)
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
150/40 (33.3)
S
OE
I
0a
–
I
0d
I
1a
–
I
1d
Z
a
–
Z
d
Common Data Select Input
3-STATE Output Enable Input (Active LOW)
Data Inputs from Source 0
Data Inputs from Source 1
3-STATE Multiplexer Outputs
Output
Select
Data
Output
Enable
Input
Inputs
OE
S
I
0
I
1
Z
H
X
X
X
Z
L
H
X
L
L
L
H
X
H
H
L
L
L
X
L
L
L
H
X
H
相關PDF資料 |
PDF描述 |
|---|---|
| 74F258ASCX | 2-Input Digital Multiplexer |
| 74F258ASJX | 2-Input Digital Multiplexer |
| 74F251ASCX | 8-Input Digital Multiplexer |
| 74F251ASJX | 8-Input Digital Multiplexer |
| 74F257A | Quad 2-line to 1-line selector/multiplexer, non-inverting 3-State |
相關代理商/技術參數 |
參數描述 |
|---|---|
| 74F257D | 制造商:North American Philips Discrete Products Div 功能描述:74F257D |
| 74F257D SIG9040 | 制造商:SIG 功能描述:74F257D |
| 74F257DSIG9040 | 制造商:SIG 功能描述:74F257D |
| 74F257N | 制造商:NXP Semiconductors 功能描述: |
| 74F257NMOT92 | 制造商:Motorola 功能描述:74F257N |
發(fā)布緊急采購，3分鐘左右您將得到回復。