SN54HC251, SN74HC251
SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
SNx4HC251 Data Selectors/Multiplexers With 3-State Outputs
1 Features
2 Description
•
•
•
The SNx4HC251 is a data selector/multiplexer
containing full binary decoding to select 1of-8 data sources and features strobe-controlled
complementary 3-state outputs.
•
•
•
•
•
•
3-state version of ’HC151
Wide operating voltage range of 2 V to 6 V
High-current 3-state outputs interface directly with
system bus or can drive up to 15 LSTTL loads
Low power consumption, 80-μA max ICC
Typical tpd = 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
Device Information
(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
SN74HC251D
SOIC (16)
9.90 mm × 3.90 mm
SN74HC251DB
SSOP (16)
6.20 mm × 5.30 mm
SN74HC251N
PDIP (16)
19.31 mm × 6.35 mm
SN74HC251NS
SO (16)
6.20 mm × 5.30 mm
SN74HC251PW
TSSOP (16)
5.00 mm × 4.40 mm
SN54HC251J
CDIP (16)
24.38 mm × 6.92 mm
SNJ54HC251FK
LCCC (20)
8.89 mm × 8.45 mm
(1)
For all available packages, see the orderable addendum at
the end of the data sheet.
Pin numbers shown are for the D, DB, J, N, NS, PW, and W packages.
Functional Block Diagram
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
SN54HC251, SN74HC251
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
Table of Contents
1 Features............................................................................1
2 Description.......................................................................1
3 Revision History.............................................................. 2
4 Pin Configuration and Functions...................................3
5 Specifications.................................................................. 4
5.1 Absolute Maximum Ratings........................................ 4
5.2 Recommended Operating Conditions(1) .................... 4
5.3 Thermal Information....................................................4
5.4 Electrical Characteristics.............................................5
5.5 Switching Characteristics ...........................................5
5.6 Switching Characteristics ...........................................6
5.7 Operating Characteristics........................................... 6
6 Parameter Measurement Information............................ 7
7 Detailed Description........................................................8
7.1 Overview..................................................................... 8
7.2 Functional Block Diagram........................................... 8
7.3 Device Functional Modes............................................9
8 Power Supply Recommendations................................10
9 Layout.............................................................................10
9.1 Layout Guidelines..................................................... 10
10 Device and Documentation Support..........................11
10.1 Receiving Notification of Documentation Updates.. 11
10.2 Support Resources................................................. 11
10.3 Trademarks............................................................. 11
10.4 Electrostatic Discharge Caution.............................. 11
10.5 Glossary.................................................................. 11
11 Mechanical, Packaging, and Orderable
Information.................................................................... 11
3 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision E (September 2003) to Revision F (February 2022)
Page
• Updated the numbering, formatting, tables, figures, and cross-refrences throughout the document to reflect
modern data sheet standards............................................................................................................................. 1
2
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
4 Pin Configuration and Functions
J, D, DB, N, NS, or PW Package
16-Pin CDIP, SOIC, SSOP, PDIP, SO, or TSSOP
Top View
NC - No internal connection
FK Package
20-Pin LCCC
Top View
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
5 Specifications
5.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
VCC
Supply voltage range
current(2)
MIN
MAX
–0.5
7
UNIT
V
IIK
Input clamp
VI < 0 or VI > VCC
±20
mA
IOK
Output clamp current(2)
VO < 0 or VO > VCC
±20
mA
IO
Continuous output current
VO = 0 to VCC
±35
mA
±70
mA
150
°C
150
°C
Continuous current through VCC or GND
TJ
Junction temperature
Tstg
Storage temperature
(1)
(2)
–65
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.
The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
5.2 Recommended Operating Conditions(1)
SN54HC251
VCC
Supply voltage
VCC = 2 V
VIH
High-level input voltage
VCC = 4.5 V
VCC = 6 V
SN74HC251
MIN
NOM
MAX
2
5
6
Low-level input voltage
VI
Input voltage
VO
Output voltage
5
6
3.15
4.2
4.2
VCC = 4.5 V
0
Input transition rise/fall time VCC = 4.5 V
Operating free-air temperature
−55
0.5
0.5
1.35
1.35
V
V
1.8
VCC
0
VCC
0
VCC
V
VCC
V
1000
1000
500
500
400
400
125
UNIT
V
1.8
0
VCC = 6 V
(1)
2
3.15
VCC = 2 V
TA
MAX
1.5
VCC = 6 V
Δt/Δv
NOM
1.5
VCC = 2 V
VIL
MIN
−40
85
ns
°C
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.
5.3 Thermal Information
THERMAL
R θJA
(1)
4
METRIC(1)
Junction-to-ambient thermal
resistance
D (SOIC)
DB (SSOP)
N (PDIP)
NS (SO)
PW (TSSOP)
16 PINS
16 PINS
16 PINS
16 PINS
16 PINS
UNIT
73
82
67
64
108
°C/W
For more information about traditional and new thermal metrics, see the Semiconductor and IC package thermal metrics application
report.
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
5.4 Electrical Characteristics
over recommended operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST
(1)
CONDITIONS
IOH = −20 μA
IOH = −6 mA
SN54HC251
TYP
2
1.9
1.998
1.9
1.9
4.5
4.4
4.499
4.4
4.4
6
5.9
5.999
5.9
5.9
4.5
3.98
4.3
3.7
3.84
6
5.48
5.8
5.2
5.34
IOH = −7.8 mA
MAX
MIN
SN74HC251
MIN
VOH
MAX
MIN
MAX
UNIT
V
2
0.002
0.1
0.1
0.1
IOL = 20 μA
4.5
0.001
0.1
0.1
0.1
6
0.001
0.1
0.1
0.1
IOL = 6 mA
4.5
0.17
0.26
0.4
0.33
IOL = 7.8 mA
6
0.15
0.26
0.4
0.33
VOL
V
II
VI = VCC or 0
6
±0.1
±100
±1000
±1000
nA
IOZ
Vo = VCC or 0
6
±0.01
±0.5
±10
±5
μA
ICC
VI = VCC or 0, IO =
0
6
8
160
80
μA
10
10
10
pF
Ci
(1)
TA = 25°C
VCC (V)
2 to 6
3
VI = VIH or VIL, unless otherwise noted.
5.5 Switching Characteristics
over recommended operating free-air temperature range, CL = 50 pF (unless otherwise noted) (see Figure 6-1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC (V)
A, B, or C
W or Y
tpd
Any D
ten
tdis
tt
OE
OE
W or Y
W or Y
W or Y
W or Y
TA = 25°C
MIN
SN54HC251
MIN
SN74HC251
TYP
MAX
MAX
MIN
MAX
2
58
205
300
256
4.5
21
41
60
51
6
19
35
51
44
2
44
195
283
244
4.5
17
39
57
49
6
15
33
48
41
2
30
145
210
181
4.5
10
29
42
36
6
9
25
36
31
2
25
195
283
244
4.5
15
39
57
49
6
14
33
48
41
2
20
75
110
95
4.5
8
15
22
19
6
6
13
19
16
UNIT
ns
ns
ns
ns
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
5.6 Switching Characteristics
over recommended operating free-air temperature range, CL = 150 pF (unless otherwise noted) (see Figure 6-1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
A, B, or C
W or Y
tpd
Any D
ten
OE
W or Y
W or Y
tt
W or Y
VCC (V)
TA = 25°C
MIN
SN54HC251
MIN
SN74HC251
MAX
MIN
UNIT
TYP
MAX
MAX
2
72
300
450
375
4.5
25
60
90
75
6
22
52
77
65
2
59
300
450
375
4.5
21
60
90
75
6
18
52
77
65
2
50
230
340
285
4.5
17
46
68
57
6
15
40
58
50
2
45
210
315
265
4.5
17
42
63
53
6
13
36
53
45
ns
ns
ns
5.7 Operating Characteristics
TA = 25℃
PARAMETER
Cpd
6
TEST CONDITIONS
Power dissipation capacitance
No load
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TYP
70
UNIT
pF
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
6 Parameter Measurement Information
Figure 6-1. Load Circuit and Voltage Waveforms
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
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7 Detailed Description
7.1 Overview
These data selectors/multiplexers contain full binary decoding to select 1-of-8 data sources and feature strobecontrolled 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.
7.2 Functional Block Diagram
Pin numbers shown are for the D, DB, J, N, NS, PW, and W packages.
8
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
7.3 Device Functional Modes
Table 7-1. Function Table(1)
INPUTS
OUTPUTS
SELECT
(1)
OE
Y
W
C
B
A
X
X
X
H
Z
Z
L
L
L
L
D0
D0
L
L
H
L
D1
D1
L
H
L
L
D2
D2
L
H
H
L
D3
D3
H
L
L
L
D4
D4
H
L
H
L
D5
D5
H
H
L
L
D6
D6
H
H
H
L
D7
D7
D0, D1 . . . D7 = the level of the respective D input.
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
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8 Power Supply Recommendations
The power supply can be any voltage between the minimum and maximum supply voltage rating located in the
Recommended Operating Conditions. Each VCC terminal should have a good bypass capacitor to prevent power
disturbance. A 0.1-μF capacitor is recommended for this device. It is acceptable to parallel multiple bypass caps
to reject different frequencies of noise. The 0.1-μF and 1-μF capacitors are commonly used in parallel. The
bypass capacitor should be installed as close to the power terminal as possible for best results.
9 Layout
9.1 Layout Guidelines
When using multiple-input and multiple-channel logic devices inputs must not ever be left floating. In many
cases, functions or parts of functions of digital logic devices are unused; for example, when only two inputs of a
triple-input AND gate are used or only 3 of the 4 buffer gates are used. Such unused input pins must not be left
unconnected because the undefined voltages at the outside connections result in undefined operational states.
All unused inputs of digital logic devices must be connected to a logic high or logic low voltage, as defined by the
input voltage specifications, to prevent them from floating. The logic level that must be applied to any particular
unused input depends on the function of the device. Generally, the inputs are tied to GND or VCC, whichever
makes more sense for the logic function or is more convenient.
10
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SCLS132F – DECEMBER 1982 – REVISED FEBRUARY 2022
10 Device and Documentation Support
TI offers an extensive line of development tools. Tools and software to evaluate the performance of the device,
generate code, and develop solutions are listed below.
10.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
10.2 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
10.3 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
10.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
10.5 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
11 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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10-Jun-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
(1)
85125012A
ACTIVE
LCCC
FK
20
1
Non-RoHS
& Green
SNPB
N / A for Pkg Type
-55 to 125
85125012A
SNJ54HC
251FK
8512501EA
ACTIVE
CDIP
J
16
1
Non-RoHS
& Green
SNPB
N / A for Pkg Type
-55 to 125
8512501EA
SNJ54HC251J
Samples
SN54HC251J
ACTIVE
CDIP
J
16
1
Non-RoHS
& Green
SNPB
N / A for Pkg Type
-55 to 125
SN54HC251J
Samples
SN74HC251D
ACTIVE
SOIC
D
16
40
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251DBR
ACTIVE
SSOP
DB
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251DE4
ACTIVE
SOIC
D
16
40
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251DG4
ACTIVE
SOIC
D
16
40
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251DR
ACTIVE
SOIC
D
16
2500
RoHS & Green
NIPDAU | SN
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251DT
ACTIVE
SOIC
D
16
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251N
ACTIVE
PDIP
N
16
25
RoHS & Green
NIPDAU
N / A for Pkg Type
-40 to 85
SN74HC251N
Samples
SN74HC251NSR
ACTIVE
SO
NS
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251PW
ACTIVE
TSSOP
PW
16
90
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251PWR
ACTIVE
TSSOP
PW
16
2000
RoHS & Green
NIPDAU | SN
Level-1-260C-UNLIM
-40 to 85
HC251
Samples
SN74HC251PWRG4
ACTIVE
TSSOP
PW
16
2000
TBD
Call TI
Call TI
-40 to 85
SN74HC251PWT
ACTIVE
TSSOP
PW
16
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
HC251
SNJ54HC251FK
ACTIVE
LCCC
FK
20
1
Non-RoHS
& Green
SNPB
N / A for Pkg Type
-55 to 125
85125012A
SNJ54HC
251FK
SNJ54HC251J
ACTIVE
CDIP
J
16
1
Non-RoHS
& Green
SNPB
N / A for Pkg Type
-55 to 125
8512501EA
SNJ54HC251J
The marketing status values are defined as follows:
Addendum-Page 1
Samples
Samples
Samples
Samples
Samples
PACKAGE OPTION ADDENDUM
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10-Jun-2022
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of