NSC DM54LS251 Tri-state data selectors/multiplexer Datasheet

DM54LS251/DM74LS251
TRI-STATEÉ Data Selectors/Multiplexers
General Description
Features
These data selectors/multiplexers contain full on-chip binary decoding to select one-of-eight data sources, and feature
a strobe-controlled TRI-STATE output. The strobe must be
at a low logic level to enable these devices. The TRI-STATE
outputs permit direct connection to a common bus. When
the strobe input is high, both outputs are in a high-impedance state in which both the upper and lower transistors of
each totem-pole output are off, and the output neither drives
nor loads the bus significantly. When the strobe is low, the
outputs are activated and operate as standard TTL totempole outputs.
To minimize the possibility that two outputs will attempt to
take a common bus to opposite logic levels, the output control circuitry is designed so that the average output disable
time is shorter than the average output enable time.
Y
Connection Diagram
Function Table
Y
Y
Y
Y
Y
Y
Y
TRI-STATE version of LS151
Interface directly with system bus
Perform parallel-to-serial conversion
Permit multiplexing from N-lines to one line
Complementary outputs provide true and inverted data
Maximum number of common outputs
54LS 49
74LS 129
Typical propagation delay time (D to Y)
54LS 17 ns
74LS 17 ns
Typical power dissipation
54LS 35 mW
74LS 35 mW
Dual-In-Line Package
Inputs
Select
Outputs
C
B
A
Strobe
S
X
L
L
L
L
H
H
H
H
X
L
L
H
H
L
L
H
H
X
L
H
L
H
L
H
L
H
H
L
L
L
L
L
L
L
L
Y
W
Z
D0
D1
D2
D3
D4
D5
D6
D7
Z
D0
D1
D2
D3
D4
D5
D6
D7
H e High Logic Level, L e Low Logic Level,
X e Don’t Care, Z e High Impedance (Off)
D0, D1 . . . D7 e The level of the respective D input
TL/F/6415 – 1
Order Number DM54LS251J, DM54LS251W,
DM74LS251M or DM74LS251N
See NS Package Number J16A, M16A, N16E or W16A
TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.
C1995 National Semiconductor Corporation
TL/F/6415
RRD-B30M105/Printed in U. S. A.
DM54LS251/DM74LS251 TRI-STATE Data Selectors/Multiplexers
June 1989
Absolute Maximum Ratings (Note)
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaranteed. 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.
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
b 55§ C to a 125§ C
DM54LS
DM74LS
0§ C to a 70§ C
b 65§ C to a 150§ C
Storage Temperature Range
Recommended Operating Conditions
Symbol
DM54LS251
Parameter
DM74LS251
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.25
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
0.7
0.8
V
IOH
High Level Output Current
b1
b 2.6
mA
IOL
Low Level Output Current
24
mA
TA
Free Air Operating Temperature
70
§C
Electrical Characteristics
Symbol
2
2
V
12
b 55
125
0
over recommended operating free air temperature range (unless otherwise noted)
Parameter
Min
Typ
(Note 1)
DM54
2.4
3.4
DM74
2.4
3.1
Conditions
Max
Units
b 1.5
V
VI
Input Clamp Voltage
VCC e Min, II e b18 mA
VOH
High Level Output
Voltage
VCC e Min, IOH e Max
VIL e Max, VIH e Min
Low Level Output
Voltage
VCC e Min, IOL e Max
VIL e Max, VIH e Min
DM54
0.25
DM74
0.35
0.5
IOL e 12 mA, VCC e Min
DM74
0.25
0.4
VOL
V
V
0.4
V
II
Input Current @ Max
Input Voltage
VCC e Max, VI e 7V
IIH
High Level Input Current
VCC e Max, VI e 2.7V
20
mA
IIL
Low Level Input Current
VCC e Max, VI e 0.4V
b 0.4
mA
IOZH
Off-State Output Current
with High Level Output
Voltage Applied
VCC e Max, VO e 2.7V
VIH e Min, VIL e Max
20
mA
Off-State Output Current
with Low Level Output
Voltage Applied
VCC e Max, VO e 0.4V
VIH e Min, VIL e Max
b 20
mA
Short Circuit
Output Current
VCC e Max
(Note 2)
ICC1
Supply Current
VCC e Max (Note 3)
6.1
10
mA
ICC2
Supply Current
VCC e Max (Note 4)
7.1
12
mA
IOZL
IOS
0.1
DM54
b 20
b 100
DM74
b 20
b 100
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: ICC1 is measured with the outputs open, STROBE grounded, and all other inputs at 4.5V.
Note 4: ICC2 is measured with the outputs open and all inputs at 4.5V.
2
mA
mA
Switching Characteristics
Symbol
Parameter
at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load)
From (Input)
to (Output)
RL e 667X
CL e 45 pF
CL e 150 pF
Min
Max
Min
Max
Units
tPLH
Propagation Delay Time
Low to High Level Output
A, B, C
(4 Levels) to Y
45
53
ns
tPHL
Propagation Delay Time
High to Low Level Output
A, B, C
(4 Levels) to Y
45
53
ns
tPLH
Propagation Delay Time
Low to High Level Output
A, B, C
(3 Levels) to W
33
38
ns
tPHL
Propagation Delay Time
High to Low Level Output
A, B, C
(3 Levels) to W
33
42
ns
tPLH
Propagation Delay Time
Low to High Level Output
D
to Y
28
35
ns
tPHL
Propagation Delay Time
High to Low Level Output
D
to Y
28
38
ns
tPLH
Propagation Delay Time
Low to High Level Output
D
to W
15
25
ns
tPHL
Propagation Delay Time
High to Low Level Output
D
to W
15
25
ns
tPZH
Output Enable Time to
High Level Output
Strobe
to Y
45
60
ns
tPZL
Output Enable Time to
Low Level Output
Strobe
to Y
40
51
ns
tPHZ
Output Disable Time from
High Level Output (Note 1)
Strobe
to Y
45
ns
tPLZ
Output Disable Time from
Low Level Output (Note 1)
Strobe
to Y
25
ns
tPZH
Output Enable Time to
High Level Output
Strobe
to W
27
40
ns
tPZL
Output Enable Time to
Low Level Output
Strobe
to W
40
47
ns
tPHZ
Output Disable Time from
High Level Output (Note 1)
Strobe
to W
55
ns
tPLZ
Output Disable Time from
Low Level Output (Note 1)
Strobe
to W
25
ns
Note 1: CL e 5 pF
Logic Diagram
TL/F/6415 – 2
3
Physical Dimensions inches (millimeters)
16-Lead Ceramic Dual-In-Line Package (J)
Order Number DM54LS251J
NS Package Number J16A
4
Physical Dimensions inches (millimeters) (Continued)
16-Lead Small Outline Molded Package (M)
Order Number DM74LS251M
NS Package Number M16A
Molded Dual-In-Line Package (N)
Order Number DM74LS251N
NS Package Number N16E
5
DM54LS251/DM74LS251 TRI-STATE Data Selectors/Multiplexers
Physical Dimensions inches (millimeters) (Continued)
16-Lead Ceramic Flat Package (W)
Order Number DM54LS251W
NS Package Number W16A
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