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DM74LS257 PDF даташит

Спецификация DM74LS257 изготовлена ​​​​«National Semiconductor» и имеет функцию, называемую «(DM74LS257 / DM74LS258) TRI-STATE Quad 2-Data Selectors/Multiplexers».

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Номер произв DM74LS257
Описание (DM74LS257 / DM74LS258) TRI-STATE Quad 2-Data Selectors/Multiplexers
Производители National Semiconductor
логотип National Semiconductor логотип 

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DM74LS257 Даташит, Описание, Даташиты
June 1989
54LS257A DM54LS257B DM74LS257B
54LS258A DM54LS258B DM74LS258B
TRI-STATE Quad 2-Data Selectors Multiplexers
General Description
These Schottky-clamped high-performance multiplexers
feature TRI-STATE outputs that can interface directly with
data lines of bus-organized systems With all but one of the
common outputs disabled (at a high impedance state) the
low impedance of the single enabled output will drive the
bus line to a high or low logic level To minimize the possibil-
ity that two outputs will attempt to take a common bus to
opposite logic levels the output enable circuitry is designed
such that the output disable times are shorter than the out-
put enable times
This TRI-STATE output feature means that n-bit (paralleled)
data selectors with up to 258 sources can be implemented
for data buses It also permits the use of standard TTL reg-
isters for data retention throughout the system
Features
Y TRI-STATE versions LS157 and LS158 with same pin-
outs
Y Schottky-clamped for significant improvement in A-C
performance
Y Provides bus interface from multiple sources in high-
performance systems
Y Average propagation delay from data input 12 ns
Y Typical power dissipation
LS257B 50 mW
LS258B 35 mW
Y Alternate military aerospace devices (54LS257A
54LS258A) are available Contact a National Semicon-
ductor Sales Office Distributor for specifications
Connection Diagrams
Dual-In-Line Package
Dual-In-Line Package
TL F 6417 – 1
Order Number 54LS257ADMQB 54LS257AFMQB
54LS257ALMQB DM54LS257BJ DM54LS257BW
DM74LS257BM or DM74LS257BN
See NS Package Number E20A J16A
M16A N16E or W16A
TL F 6417 – 2
Order Number 54LS258ADMQB 54LS258AFMQB
54LS258ALMQB DM54LS258BJ DM54LS258BW
DM74LS258BM or DM74LS258BN
See NS Package Number E20A J16A
M16A N16E or W16A
Function Table
Inputs
Output Y
Output
Control
Select
A
B
LS257
LS258
H
X XX Z
Z
L
L LX L
H
L
L HX H
L
L
H XL L
H
L
H XH H
L
H e High Level L e Low Level X e Don’t Care
Z e High Impedance (off)
TRI-STATE is a registered trademark of National Semiconductor Corporation
C1995 National Semiconductor Corporation TL F 6417
RRD-B30M105 Printed in U S A









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DM74LS257 Даташит, Описание, Даташиты
Absolute Maximum Ratings (Note)
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range
DM54LS and 54LS
b55 C to a125 C
DM74LS
0 C to a70 C
Storage Temperature Range
b65 C to a150 C
Note The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaran-
teed The device should not be operated at these limits The
parametric values defined in the ‘‘Electrical Characteristics’’
table are not guaranteed at the absolute maximum ratings
The ‘‘Recommended Operating Conditions’’ table will define
the conditions for actual device operation
Recommended Operating Conditions
Symbol
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage
High Level Input Voltage
Low Level Input Voltage
High Level Output Current
Low Level Output Current
Free Air Operating Temperature
DM54LS257B
Min Nom
45 5
2
b55
Max
55
07
b1
12
125
DM74LS257B
Min
Nom
Max
4 75 5 5 25
2
08
b2 6
24
0 70
Units
V
V
V
mA
mA
C
’LS257B Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
(Note 1)
VI Input Clamp Voltage
VOH
High Level Output
Voltage
VCC e Min II e b18 mA
VCC e Min IOH e Max
VIL e Max VIH e Min
DM54
DM74
24
24
34
31
VOL Low Level Output
Voltage
VCC e Min IOL e Max
VIL e Max VIH e Min
DM54
DM74
0 25
0 35
IOL e 12 mA VCC e Min
DM74
II
Input Current Max
VCC e Max
Input Voltage
VI e 7V
Select
Other
0 25
IIH High Level Input
Current
VCC e Max
VI e 2 7V
Select
Other
IIL Low Level Input
Current
VCC e Max
VI e 0 4V
Select
Other
IOZH
Off-State Output Current
with High Level Output
Voltage Applied
VCC e Max VO e 2 7V
VIH e Min VIL e Max
IOZL
Off-State Output Current
with Low Level Output
Voltage Applied
VCC e Max VO e 0 4V
VIH e Min VIL e Max
IOS Short Circuit
Output Current
VCC e Max
(Note 2)
DM54
DM74
b20
b20
ICCH
Supply Current with
Outputs High
VCC e Max (Note 3)
59
ICCL
Supply Current with
Outputs Low
VCC e Max (Note 3)
92
ICCZ
Supply Current with
Outputs Disabled
VCC e Max (Note 3)
12
Note 1 All typicals are at VCC e 5V TA e 25 C
Note 2 Not more than one output should be shorted at a time and the duration should not exceed one second
Note 3 ICC is measured with all outputs open and all possible inputs grounded while achieving the stated output conditions
Max
b1 5
04
05
04
02
01
40
20
b0 8
b0 4
20
b20
b100
b100
10
16
19
Units
V
V
V
mA
mA
mA
mA
mA
mA
mA
mA
mA
2









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DM74LS257 Даташит, Описание, Даташиты
’LS257B Switching Characteristics
at VCC e 5V and TA e 25 C (See Section 1 for Test Waveforms and Output Load)
Symbol
Parameter
From (Input)
To (Output)
RL e 667X
CL e 45 pF
CL e 150 pF
Min Max Min Max
tPLH
Propagation Delay Time
Data to
18
27
Low to High Level Output
Output
tPHL
Propagation Delay Time
Data to
18
27
High to Low Level Output
Output
tPLH
Propagation Delay Time
Low to High Level Output
Select to
Output
28
35
tPHL
Propagation Delay Time
High to Low Level Output
Select to
Output
35
42
tPZH
Output Enable Time
to High Level Output
Output
Control to Y
15
27
tPZL Output Enable Time
to Low Level Output
Output
Control to Y
28
38
tPHZ
Output Disable Time from
High Level Output (Note 1)
Output
Control to Y
26
tPLZ Output Disable Time from
Low Level Output (Note 1)
Note 1 CL e 5 pF
Output
Control to Y
25
Recommended Operating Conditions
Symbol
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage
High Level Input Voltage
Low Level Input Voltage
High Level Output Current
Low Level Output Current
Free Air Operating Temperature
DM54LS258B
Min
Nom
Max
45 5 55
2
07
b1
12
b55
125
DM74LS258B
Min
Nom
Max
4 75 5 5 25
2
08
b2 6
24
0 70
’LS258B Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
VI
VOH
VOL
Parameter
Input Clamp Voltage
High Level Output
Voltage
Low Level Output
Voltage
II Input Current Max
Input Voltage
IIH High Level Input
Current
Conditions
VCC e Min II e b18 mA
VCC e Min IOH e Max
VIL e Max VIH e Min
VCC e Min IOL e Max
VIL e Max VIH e Min
IOL e 12 mA VCC e Min
VCC e Max
VI e 7V
VCC e Max
VI e 2 7V
DM54
DM74
DM54
DM74
DM74
Select
Other
Select
Other
Min
24
24
Typ
(Note 1)
34
31
0 25
0 35
0 25
Max
b1 5
04
05
04
02
01
40
20
Units
ns
ns
ns
ns
ns
ns
ns
ns
Units
V
V
V
mA
mA
C
Units
V
V
V
mA
mA
3










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