SCLS132E − DECEMBER 1982 − REVISED SEPTEMBER 2003
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3 STATE OUTPUTS
D
3-State Version of ’HC151
D
Wide Operating Voltage Range of 2 V to 6 V
D
High-Current 3-State Outputs Interface
D
D
D
D
D
D
Directly With System Bus or Can Drive Up
To 15 LSTTL Loads
Low Power Consumption, 80-µA Max I
CC
Typical t
pd
= 9 ns
±6-mA
Output Drive at 5 V
Low Input Current of 1
µA
Max
Perform Parallel-to-Serial Conversion
Complementary Outputs Provide True and
Inverted Data
SN54HC251 . . . J OR W PACKAGE
SN74HC251 . . . D, DB, N, NS, OR PW 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
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.
ORDERING INFORMATION
TA
PDIP − N
PACKAGE†
Tube of 25
Tube of 40
SOIC − D
−40 C 85°C
−40°C to 85 C
SOP − NS
SSOP − DB
Reel of 2500
Reel of 250
Reel of 2000
Reel of 2000
Tube of 90
TSSOP − PW
CDIP − J
−55 C 125°C
−55°C to 125 C
CFP − W
LCCC − FK
Reel of 2000
Reel of 250
Tube of 25
Tube of 150
Tube of 55
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
ORDERABLE
PART NUMBER
SN74HC251N
SN74HC251D
SN74HC251DR
SN74HC251DT
SN74HC251NSR
SN74HC251DBR
SN74HC251PW
SN74HC251PWR
SN74HC251PWT
SNJ54HC251J
SNJ54HC251W
SNJ54HC251FK
SNJ54HC251J
SNJ54HC251W
SNJ54HC251FK
HC251
HC251
HC251
HC251
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.
description/ordering information
SN54HC251 . . . FK PACKAGE
(TOP VIEW)
† Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are
available at www.ti.com/sc/package.
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.
Copyright
2003, Texas Instruments Incorporated
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
OE
GND
NC
C
B
TOP-SIDE
MARKING
SN74HC251N
1
SCLS132E − DECEMBER 1982 − REVISED SEPTEMBER 2003
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3 STATE OUTPUTS
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
Y
Z
D0
D1
D2
D3
D4
D5
D6
D7
W
Z
D0
D1
D2
D3
D4
D5
D6
D7
OUTPUTS
D0, D1 . . . D7 = the level of the respective D input
2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SCLS132E − DECEMBER 1982 − REVISED SEPTEMBER 2003
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3 STATE OUTPUTS
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, NS, PW, and W packages.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
3
SCLS132E − DECEMBER 1982 − REVISED SEPTEMBER 2003
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3 STATE OUTPUTS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
†
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73°C/W
DB package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82°C/W
N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67°C/W
NS package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64°C/W
PW package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108°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 51-7.
recommended operating conditions (see Note 3)
SN54HC251
MIN
VCC
VIH
Supply voltage
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 2 V
VIL
VI
VO
∆t/∆v
Low-level input voltage
Input voltage
Output voltage
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 4.5 V
VCC = 6 V
0
0
2
1.5
3.15
4.2
0.5
1.35
1.8
VCC
VCC
1000
500
400
0
0
NOM
5
MAX
6
SN74HC251
MIN
2
1.5
3.15
4.2
0.5
1.35
1.8
VCC
VCC
1000
500
400
ns
V
V
V
V
NOM
5
MAX
6
UNIT
V
High-level input voltage
Input transition rise/fall time
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
SCLS132E − DECEMBER 1982 − REVISED SEPTEMBER 2003
SN54HC251, SN74HC251
DATA SELECTORS/MULTIPLEXERS
WITH 3 STATE OUTPUTS
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
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
•
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5
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