SN54F251B, SN74F251B
1-OF-8 DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SDFS066A – MARCH 1987 – REVISED OCTOBER 1993
•
•
•
•
•
3-State Versions of SN54F151B and
SN74F151B
3-State Outputs Interface Directly With
System Bus
Performs Parallel-to-Serial Conversion
Complementary Outputs Provide True and
Inverted Data
Package Options Include Plastic
Small-Outline Packages, Ceramic Chip
Carriers, and Standard Plastic and Ceramic
300-mil DIPs
SN54F251B . . . J PACKAGE
SN74F251B . . . D OR N PACKAGE
(TOP VIEW)
D3
D2
D1
D0
Y
W
G
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
D4
D5
D6
D7
A
B
C
description
These data selectors/multiplexers contain full
binary decoding to select one of eight data
sources
and
feature
strobe-controlled
complementary outputs. The 3-state outputs can
interface with and drive data lines of bus-
organized systems. When the strobe (G) 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.
The SN54F251B is characterized for operation
over the full military temperature range of – 55°C
to 125°C. The SN74F251B is characterized for
operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
SELECT
C
X
L
L
L
L
H
H
H
H
B
X
L
L
H
H
L
L
H
H
A
X
L
H
L
H
L
H
L
H
STROBE
G
H
L
L
L
L
L
L
L
L
SN54F251B . . . FK PACKAGE
(TOP VIEW)
D1
D0
NC
Y
W
4
5
6
7
8
3 2 1 20 19
18
17
16
15
14
9 10 11 12 13
D2
D3
NC
VCC
D4
D5
D6
NC
D7
A
NC – No internal connection
OUTPUTS
Y
Z
D0
D1
D2
D3
D4
D5
D6
D7
W
Z
D0
D1
D2
D3
D4
D5
D6
D7
Copyright
©
1993, Texas Instruments Incorporated
D0, D1, . . . D7 = the level of the respective D input.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
G
GND
NC
C
B
2–1
SN54F251B, SN74F251B
1-OF-8 DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SDFS066A – MARCH 1987 – REVISED OCTOBER 1993
logic symbol
†
G
A
B
C
D0
D1
D2
D3
D4
D5
D6
D7
7
11
10
9
4
3
2
1
15
14
13
12
2
0
1
2
3
4
5
6
7
5
6
Y
W
MUX
EN
0
0
G7
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, and N packages.
2–2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54F251B, SN74F251B
1-OF-8 DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SDFS066A – MARCH 1987 – REVISED OCTOBER 1993
logic diagram (positive logic)
G
D0
7
4
D1
3
D2
2
D3
Data
Inputs
D4
1
5
15
6
Y
W
D5
14
D6
13
D7
12
A
Data
Select
(Binary)
11
B
10
C
9
Pin numbers shown are for the D, J, and N packages.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
†
Supply voltage range, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
Input voltage range (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 1.2 V to 7 V
Input current range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 30 mA to 5 mA
Voltage range applied to any output in the disabled or power-off state . . . . . . . . . . . . . . . . . . . – 0.5 V to 5.5 V
Voltage range applied to any output in the high state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to V
CC
Current into any output in the low state: SN54F251B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 mA
SN74F251B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 mA
Operating free-air temperature range: SN54F251B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 125°C
SN74F251B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: The input voltage ratings may be exceeded provided the input current ratings are observed.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
2–3
SN54F251B, SN74F251B
1-OF-8 DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SDFS066A – MARCH 1987 – REVISED OCTOBER 1993
recommended operating conditions
SN54F251B
MIN
VCC
VIH
VIL
IIK
IOH
IOL
TA
Supply voltage
High-level input voltage
Low-level input voltage
Input clamp current
High-level output current
Low-level output current
Operating free-air temperature
– 55
4.5
2
0.8
– 18
–3
20
125
0
NOM
5
MAX
5.5
SN74F251B
MIN
4.5
2
0.8
– 18
–3
24
70
NOM
5
MAX
5.5
UNIT
V
V
V
mA
mA
mA
°C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
VOH
VCC = 4.5 V,
VCC = 4 5 V
4.5
VCC = 4.75 V,
VOL
IOZH
IOZL
II
IIH
IIL
IOS‡
ICC
VCC = 4 5 V
4.5
VCC = 5.5 V,
VCC = 5.5 V,
VCC = 5.5 V,
VCC = 5.5 V,
VCC = 5.5 V,
VCC = 5.5 V,
VCC = 5.5 V,
See Note 2
TEST CONDITIONS
II = – 18 mA
IOH = – 1 mA
IOH = – 3 mA
IOH = – 1 mA to – 3 mA
IOL = 20 mA
IOL = 24 mA
VO = 2.7 V
VO = 0.5 V
VI = 7 V
VI = 2.7 V
VI = 0.5 V
VO = 0
Condition A
Condition B
– 60
15
16
SN54F251B
MIN TYP†
MAX
– 1.2
2.5
2.4
3.4
3.3
0.3
0.5
0.35
50
– 50
0.1
20
– 0.6
–150
22
24
– 60
15
16
0.5
50
– 50
0.1
20
– 0.6
–150
22
24
2.5
2.4
2.7
V
µA
µA
mA
µA
mA
mA
mA
3.4
3.3
V
SN74F251B
MIN TYP†
MAX
– 1.2
UNIT
V
† All typical values are at VCC = 5 V, TA = 25°C.
‡ Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second.
NOTE 2: ICC is measured with the outputs open under the following conditions:
A. Select input and data input at 4.5 V, output control grounded
B. All inputs at 4.5 V
2–4
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54F251B, SN74F251B
1-OF-8 DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SDFS066A – MARCH 1987 – REVISED OCTOBER 1993
switching characteristics (see Note 3)
VCC = 5 V,
CL = 50 pF,
R1 = 500
Ω,
R2 = 500
Ω,
TA = 25°C
′F251B
MIN
tPLH
tPHL
tPLH
tPHL
tPLH
tPHL
tPLH
tPHL
tPZH
tPZL
tPHZ
tPLZ
tPZH
tPZL
tPHZ
tPLZ
A B, or C
A, B
A, B
A B, or C
Any D
Any D
W
Y
W
Y
W
W
Y
Y
3.5
2.5
4.5
4
2.5
1
3
3
2.5
2.5
1.9
1
3.4
2.9
1.9
1
TYP
5.4
4.4
6.2
6
3.7
1.9
3.8
4.5
3.6
3.8
2.5
2.4
4.8
4
2.5
2.3
MAX
9
7.5
10.5
8.5
6.5
4
7
7
6
6
5.5
4.5
7
7.5
5.5
4.5
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
R1 = 500
Ω,
R2 = 500
Ω,
TA = MIN to MAX †
SN54F251B
MIN
3.5
2.5
3.5
3
1.8
1
2.3
2.3
2
2.5
1.4
1
2.7
2.6
1.7
1
MAX
11.5
8
14
10.9
8
6
9
9
7
7.5
6
5
8.5
9
5.5
5.5
SN74F251B
MIN
3.5
2.5
4
3.5
2
1
2.3
2.5
2
2.5
1.5
1
2.9
2.6
1.8
1
MAX
9.5
7.5
12.5
9
7
5
8
8
7
6.5
6
4.5
8.5
8
5.5
4.5
ns
ns
ns
ns
ns
ns
ns
ns
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
UNIT
G
G
G
G
† For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
NOTE 3: Load circuits and waveforms are shown in Section 1.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
2–5
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