SN54HCT257_14 [TI]
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS;
| 型号： | SN54HCT257_14 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS WITH 3-STATE OUTPUTS 输出元件 |
| 文件： | 总6页 (文件大小：113K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SN54HCT257, SN74HCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS072B – NOVEMBER 1988 – REVISED MAY 1997
SN54HCT257 . . . J PACKAGE
SN74HCT257 . . . N PACKAGE
(TOP VIEW)
Inputs Are TTL-Voltage Compatible
Provide Bus Interface From Multiple
Sources in High-Performance Systems
High-Current 3-State Outputs Interface
Directly With System Bus
A/B
1A
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
OE
4A
4B
1B
Buffered Inputs and Outputs
1Y
Package Options Include Ceramic Chip
Carriers (FK) and Standard Plastic (N) and
Ceramic (J) 300-mil DIPs
2A
12 4Y
11
10
9
2B
3A
3B
3Y
2Y
GND
description
The ’HCT257 are designed to multiplex signals
from 4-bit data sources to 4-output data lines in
bus-organized systems. The 3-state outputs do
not load the data lines when the output-enable
(OE) input is at the high logic level.
SN54HCT257 . . . FK PACKAGE
(TOP VIEW)
3
2
1
20 19
18
The SN54HCT257 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74HCT257 is characterized for
operation from –40°C to 85°C.
4A
4B
NC
1B
1Y
NC
2A
2B
4
5
6
7
8
17
16
15 4Y
14
9 10 11 12 13
3A
FUNCTION TABLE
INPUTS
OUTPUT
DATA
SELECT
A/B
Y
OE
A
X
L
B
X
X
X
L
NC – No internal connection
H
L
L
L
L
X
L
Z
L
L
H
X
X
H
L
H
H
H
H
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.
Copyright 1997, Texas Instruments Incorporated
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information 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.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54HCT257, SN74HCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS072B – NOVEMBER 1988 – REVISED MAY 1997
†
logic symbol
15
OE
EN
G1
1
A/B
2
4
7
1A
1B
2A
2B
3A
3B
4A
4B
1
1
MUX
1Y
2Y
3
5
6
11
10
14
13
9
3Y
4Y
12
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the J and N packages.
logic diagram (positive logic)
15
OE
1
A/B
2
1A
4
7
1Y
2Y
3Y
4Y
3
1B
5
2A
6
2B
11
3A
9
10
3B
14
4A
12
13
4B
Pin numbers shown are for the J and N packages.
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54HCT257, SN74HCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS072B – NOVEMBER 1988 – REVISED MAY 1997
†
absolute maximum ratings over operating free-air temperature range
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
CC
I
Input clamp current, I (V < 0 or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
IK
I
CC
Output clamp current, I
(V < 0 or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
OK
O O CC
Continuous output current, I (V = 0 to V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±35 mA
Continuous current through V
Package thermal impedance, θ (see Note 2): N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78°C/W
Storage temperature range, T
O
O
CC
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±70 mA
JA
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
SN54HCT257
MIN NOM MAX
SN74HCT257
MIN NOM MAX
UNIT
V
V
V
V
V
Supply voltage
4.5
2
5
5.5
4.5
2
5
5.5
V
V
CC
IH
IL
I
High-level input voltage
Low-level input voltage
Input voltage
V
V
= 4.5 V to 5.5 V
= 4.5 V to 5.5 V
CC
0
0.8
0
0.8
V
CC
0
V
V
0
V
V
V
CC
CC
Output voltage
0
0
V
O
CC
CC
t
Input transition (rise and fall) time
Operating free-air temperature
0
500
125
0
500
85
ns
°C
t
T
–55
–40
A
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
T
= 25°C
SN54HCT257 SN74HCT257
A
PARAMETER
TEST CONDITIONS
V
UNIT
V
CC
MIN
TYP
MAX
MIN
4.4
MAX
MIN
4.4
MAX
I
I
I
I
= –20 µA
= –6 mA
= 20 µA
= 6 mA
4.4 4.499
OH
OH
OL
OL
V
V = V or V
IH
4.5 V
4.5 V
OH
OL
I
IL
IL
3.98
4.3
0.001
0.17
3.7
3.84
0.1
0.26
±100
±0.5
8
0.1
0.4
0.1
0.33
±1000
±5
V
V = V or V
V
I
IH
I
I
I
V = V
I
or 0
5.5 V
5.5 V
5.5 V
±0.1
±1000
±10
nA
µA
µA
I
CC
V
O
= V
or 0,
V = V or V
±0.01
OZ
CC
CC
or 0,
I
IH
IL
V = V
I
I
O
= 0
160
80
CC
One input at 0.5 V or 2.4 V,
Other inputs at 0 or V
‡
5.5 V
1.4
3
2.4
10
3
2.9
10
mA
pF
∆I
CC
CC
4.5 V
to 5.5 V
C
10*
i
* On products compliant to MIL-PRF-38535, this parameter is not production tested.
‡
This is the increase in supply current for each input that is at one of the specified TTL voltage levels rather than 0 V or V
CC
.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54HCT257, SN74HCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS072B – NOVEMBER 1988 – REVISED MAY 1997
switching characteristics over recommended operating free-air temperature range, C = 50 pF
L
(unless otherwise noted) (see Figure 1)
T
A
= 25°C
TYP
20
SN54HCT257 SN74HCT257
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
V
UNIT
CC
MIN
MAX
30
27
30
27
30
27
30
27
15
14
MIN
MAX
45
40
45
40
45
40
45
40
22
21
MIN
MAX
38
34
38
34
38
34
38
34
19
17
4.5 V
5.5 V
4.5 V
5.5 V
4.5 V
5.5 V
4.5 V
5.5 V
4.5 V
5.5 V
A or B
Y
Y
17
t
pd
ns
20
A/B
OE
OE
17
20
t
t
t
Y
ns
ns
ns
en
dis
t
17
20
Y
17
8
Any
7
switching characteristics over recommended operating free-air temperature range, C = 150 pF
L
(unless otherwise noted) (see Figure 1)
T
A
= 25°C
TYP
22
SN54HCT257 SN74HCT257
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
V
UNIT
CC
MIN
MAX
38
MIN
MAX
57
MIN
MAX
48
4.5 V
5.5 V
4.5 V
5.5 V
4.5 V
5.5 V
4.5 V
5.5 V
A or B
A/B
Y
Y
19
35
53
44
t
pd
ns
22
38
57
48
19
35
53
44
23
40
60
50
t
t
Y
ns
ns
OE
en
20
38
57
48
17
42
63
53
Any
t
14
38
57
48
operating characteristics, T = 25°C
A
PARAMETER
TEST CONDITIONS
TYP
UNIT
C
Power dissipation capacitance
No load
13
pF
pd
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN54HCT257, SN74HCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS072B – NOVEMBER 1988 – REVISED MAY 1997
PARAMETER MEASUREMENT INFORMATION
V
CC
PARAMETER
R
C
S1
S2
L
L
50 pF
or
150 pF
t
Open
Closed
Closed
Open
S1
S2
PZH
Test
Point
t
t
1 kΩ
1 kΩ
en
R
t
L
PZL
From Output
Under Test
t
t
Open
Closed
Open
PHZ
PLZ
50 pF
C
dis
L
Closed
(see Note A)
50 pF
or
150 pF
t
or t
––
Open
Open
pd
t
LOAD CIRCUIT
1.3 V
3 V
0 V
Output
Control
(Low-Level
Enabling)
3 V
0 V
Input
1.3 V
1.3 V
1.3 V
t
t
PLH
PHL
90%
t
t
PLZ
PZL
V
V
OH
In-Phase
Output
≈ V
Output
Waveform 1
(See Note B)
CC
90%
t
1.3 V
10%
1.3 V
1.3 V
10%
t
10%
90%
OL
V
OL
r
f
f
t
t
t
PHL
90%
PLH
PZH
Out-of-
Phase
Output
V
V
OH
V
OH
Output
Waveform 2
(See Note B)
90%
t
1.3 V
10%
1.3 V
10%
1.3 V
OL
≈ 0 V
t
t
r
PHZ
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES FOR 3-STATE OUTPUTS
VOLTAGE WAVEFORMS
OUTPUT AND 3-STATE BIDIRECTIONAL I/O
PROPAGATION DELAY TIME
NOTES: A.
C includes probe and test-fixture capacitance.
L
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by generators having the following
characteristics: PRR ≤ 1 MHz, Z = 50 Ω, t = 6 ns, t = 6 ns.
O
r
f
D. The outputs are measured one at a time with one input transition per measurement.
E.
F.
G.
t
t
t
and t
and t
and t
are the same as t
are the same as t
are the same as t
.
dis
en
.
pd
PLZ
PZL
PLH
PHZ
PZH
PHL
.
Figure 1. Load Circuit and Voltage Waveforms
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
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