SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS132C – DECEMBER 1982 – REVISED FEBRUARY 1999
D
D
D
D
D
3-State Version of ’HC151
High-Current 3-State Outputs Interface
Directly With System Bus or Can Drive up
to 15 LSTTL Loads
Perform Parallel-to-Serial Conversion
Complementary Outputs Provide True and
Inverted Data
Package Options Include Plastic
Small-Outline (D), Shrink Small-Outline
(DB), and Ceramic Flat (W) Packages,
Ceramic Chip Carriers (FK), and Standard
Plastic (N) and Ceramic (J) DIPs
SN54HC251 . . . J OR W PACKAGE
SN74HC251 . . . D, DB, OR N PACKAGE
(TOP VIEW)
D3
D2
D1
D0
Y
W
OE
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 1-of-8 data sources and
feature strobe-controlled complementary 3-state
outputs.
The 3-state outputs can interface with and drive
data lines of bus-organized systems. With all but
one of the common outputs disabled (in the
high-impedance state), the low impedance of the
single enabled output drives the bus line to a high
or low logic level. Both outputs are controlled by
the output-enable (OE) input. The outputs are
disabled when OE is high.
The SN54HC251 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74HC251 is characterized for
operation from –40°C to 85
°C.
SN54HC251 . . . 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
V
CC
D4
D5
D6
NC
D7
A
NC – No internal connection
Copyright
©
1999, Texas Instruments Incorporated
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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
OE
GND
NC
C
B
1
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS132C – DECEMBER 1982 – REVISED FEBRUARY 1999
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
OE
H
L
L
L
L
L
L
L
L
OUTPUTS
Y
Z
D0
D1
D2
D3
D4
D5
D6
D7
W
Z
D0
D1
D2
D3
D4
D5
D6
D7
D0, D1 . . . D7 = the level of the respective D input
logic symbol
†
OE
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, DB, J, N, and W packages.
2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS132C – DECEMBER 1982 – REVISED FEBRUARY 1999
logic diagram (positive logic)
OE
7
11
A
B
C
10
9
D0
D1
4
TG
3
TG
D2
2
TG
5
D3
1
TG
Y
D4
15
TG
6
D5
14
13
TG
TG
W
D6
D7
12
TG
Pin numbers shown are for the D, DB, J, N, and W packages.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
3
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS132C – DECEMBER 1982 – REVISED FEBRUARY 1999
absolute maximum ratings over operating free-air temperature range
†
Supply voltage range, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input clamp current, I
IK
(V
I
< 0 or V
I
> V
CC
) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±20
mA
Output clamp current, I
OK
(V
O
< 0 or V
O
> V
CC
) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±20
mA
Continuous output current, I
O
(V
O
= 0 to V
CC
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±35
mA
Continuous current through V
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±70
mA
Package thermal impedance,
θ
JA
(see Note 2): D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113°C/W
DB package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131°C/W
N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78°C/W
Storage temperature range, T
stg
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –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.
NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace
length of zero.
recommended operating conditions (see Note 3)
SN54HC251
MIN
VCC
VIH
Supply voltage
High-level input voltage
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 2 V
VIL
VI
VO
tt
Low-level input voltage
Input voltage
Output voltage
Input transition (rise and fall) time
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 4.5 V
VCC = 6 V
2
1.5
3.15
4.2
0
0
0
0
0
0
0
0
0.5
1.35
1.8
VCC
VCC
1000
500
400
NOM
5
MAX
6
SN74HC251
MIN
2
1.5
3.15
4.2
0
0
0
0
0
0
0
0
0.5
1.35
1.8
VCC
VCC
1000
500
400
ns
V
V
V
V
NOM
5
MAX
6
UNIT
V
TA
Operating free-air temperature
–55
125
–40
85
°C
NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs,
literature number SCBA004.
4
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS132C – DECEMBER 1982 – REVISED FEBRUARY 1999
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
2V
IOH = –20
µA
VOH
VI = VIH or VIL
IOH = –6 mA
IOH = –7.8 mA
IOL = 20
µA
VOL
VI = VIH or VIL
IOL = 6 mA
IOL = 7.8 mA
II
IOZ
ICC
Ci
VI = VCC or 0
VO = VCC or 0,
VI = VCC or 0,
VI = VIH or VIL
IO = 0
4.5 V
6V
4.5 V
6V
2V
4.5 V
6V
4.5 V
6V
6V
6V
6V
2 V to 6 V
3
TA = 25°C
MIN
TYP
MAX
1.9
4.4
5.9
3.98
5.48
1.998
4.499
5.999
4.3
5.8
0.002
0.001
0.001
0.17
0.15
±0.1
±0.01
0.1
0.1
0.1
0.26
0.26
±100
±0.5
8
10
SN54HC251
MIN
1.9
4.4
5.9
3.7
5.2
0.1
0.1
0.1
0.4
0.4
±1000
±10
160
10
MAX
SN74HC251
MIN
1.9
4.4
5.9
3.84
5.34
0.1
0.1
0.1
0.33
0.33
±1000
±5
80
10
nA
µA
µA
pF
V
V
MAX
UNIT
switching characteristics over recommended operating free-air temperature range, C
L
= 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC
2V
A, B, or C
tpd
d
Any D
W or Y
W or Y
4.5 V
6V
2V
4.5 V
6V
2V
ten
OE
W or Y
4.5 V
6V
2V
tdis
OE
W or Y
4.5 V
6V
2V
tt
W or Y
4.5 V
6V
TA = 25°C
MIN
TYP
MAX
58
21
19
44
17
15
30
10
9
25
15
14
20
8
6
205
41
35
195
39
33
145
29
25
195
39
33
75
15
13
SN54HC251
MIN
MAX
300
60
51
283
57
48
210
42
36
283
57
48
110
22
19
SN74HC251
MIN
MAX
256
51
44
244
49
41
181
36
31
244
49
41
95
19
16
ns
ns
ns
ns
UNIT
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
