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參數(shù)資料
| 型號： | SN74LS257N |
| 廠商： | Motorola, Inc. |
| 英文描述： | QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS |
| 中文描述： | 四2輸入多路復(fù)用器與三態(tài)輸出 |
| 文件頁數(shù)： | 3/6頁 |
| 文件大?。?/td> | 182K |
| 代理商： | SN74LS257N |
5-429
FAST AND LS TTL DATA
SN54/74LS257B SN54/74LS258B
FUNCTIONAL DESCRIPTION
The LS257B and LS258B are Quad 2-Input Multiplexers
with 3-state outputs. They select four bits of data from two
sources each under control of a Common Data Select Input.
When the Select Input is LOW, the I0 inputs are selected and
when Select is HIGH, the I1 inputs are selected. The data on
the selected inputs appears at the outputs in true (non-
inverted) form for the LS257B and in the inverted form for the
LS258B.
The LS257B and LS258B are 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 equations for the outputs are shown below:
LS257B
Za = E0
(I1a
S + I0a
S) Zb = E0
(I1b
S + I0b
S)
Zc = E0
(I1c
S + I0c
S) Zd = E0
(I1d
S + I0d
S)
When the Output Enable Input (E0) 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 that Output Enable signals
to 3-state devices whose outputs are tied together are
designed so there is no overlap.
LS258B
Za = E0
(I1a
S + I0a
S) Zb = E0
(I1b
S + I0b
S)
Zc = E0
(I1c
S + I0c
S) Zd = E0
(I1d
S + I0d
S)
TRUTH TABLE
OUTPUT
ENABLE
SELECT
INPUT
DATA
INPUTS
OUTPUTS
LS257B
OUTPUTS
LS258B
EO
H
L
L
L
L
S
I0
X
X
X
L
H
I1
X
L
H
X
X
Z
Z
X
H
H
L
L
(Z)
L
H
L
H
(Z)
H
L
H
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
(Z) = High Impedance (off)
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
Typ
Max
Unit
VCC
Supply Voltage
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°
C
IOH
Output Current — High
54
74
–1.0
–2.6
mA
IOL
Output Current — Low
54
74
12
24
mA
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SN74LS258BD | LOW POWER SCHOTTKY |
| SN74LS258BN | 3V PA/Driver, +22dBm PSAT, 0.5-6GHz, SOT363(SC-70) |
| SN74LS259 | LOW POWER SCHOTTKY |
| SN74LS259D | LOW POWER SCHOTTKY |
| SN74LS259N | LOW POWER SCHOTTKY |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SN74LS258AJ | 制造商:Texas Instruments 功能描述: |
| SN74LS258AJD | 制造商:Motorola Inc 功能描述: |
| SN74LS258AN | 制造商:Motorola Inc 功能描述: 制造商:Motorola Inc 功能描述:LS SERIES, QUAD 2 LINE TO 1 LINE MULTIPLEXER, INVERTED OUTPUT, PDIP16 |
| SN74LS258AND | 制造商:Motorola Inc 功能描述: |
| SN74LS258ANDS | 制造商:Motorola Inc 功能描述: |
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