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SN54LS240, SN54LS241, SN54LS244, SN54S240, SN54S241, SN54S244
SN74LS240, SN74LS241, SN74LS244, SN74S240, SN74S241, SN74S244
OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS
SDLS144C − APRIL 1985 − REVISED MAY 2010
D
3-State Outputs Drive Bus Lines or Buffer
D
D
Memory Address Registers
PNP Inputs Reduce DC Loading
Hysteresis at Inputs Improves Noise
Margins
SN54LS’, SN54S’ . . . J OR W PACKAGE
SN74LS240, SN74LS244 . . . DB, DW, N, OR NS PACKAGE
SN74LS241 . . . DW, N, OR NS PACKAGE
SN74S’ . . . DW OR N PACKAGE
(TOP VIEW)
description
These octal buffers and line drivers are designed
specifically to improve both the performance and
density of three-state memory address drivers,
clock drivers, and bus-oriented receivers and
transmitters. The designer has a choice of
selected combinations of inverting and
noninverting outputs, symmetrical, active-low
output-control (G) inputs, and complementary
output-control (G and G) inputs. These devices
feature high fan-out, improved fan-in, and 400-mV
noise margin. The SN74LS’ and SN74S’ devices
can be used to drive terminated lines down to
133
Ω.
1G
1A1
2Y4
1A2
2Y3
1A3
2Y2
1A4
2Y1
GND
†
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
CC
2G/2G
†
1Y1
2A4
1Y2
2A3
1Y3
2A2
1Y4
2A1
2G for ’LS241 and ’S241 or 2G for all other drivers.
SN54LS’, SN54S’ . . . FK PACKAGE
(TOP VIEW)
1A2
2Y3
1A3
2Y2
1A4
4
5
6
7
8
3 2 1 20 19
18
17
16
15
14
9 10 11 12 13
2Y4
1A1
1G
V
CC
2G/2G
1Y1
2A4
1Y2
2A3
1Y3
†
2G for ’LS241 and ’S241 or 2G for all other drivers.
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
2010, 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.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
2Y1
GND
2A1
1Y4
2A2
†
1
SN54LS240, SN54LS241, SN54LS244, SN54S240, SN54S241, SN54S244
SN74LS240, SN74LS241, SN74LS244, SN74S240, SN74S241, SN74S244
OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS
SDLS144C − APRIL 1985 − REVISED MAY 2010
ORDERING INFORMATION
{
T
A
PACKAGE
}
ORDERABLE PART NUMBER
SN74LS240N
SN74LS241N
PDIP − N
Tube
SN74LS244N
SN74S240N
SN74S241N
SN74S244N
Tube
Tape and reel
Tube
Tape and reel
Tube
0°C to 70°C
SOIC − DW
Tape and reel
Tube
Tape and reel
Tube
Tape and reel
Tube
Tape and reel
SN74LS240DW
SN74LS240DWR
SN74LS241DW
SN74LS241DWR
SN74LS244DW
SN74LS244DWR
SN74S240DW
SN74S240DWR
SN74S241DW
SN74S241DWR
SN74S244DW
SN74S244DWR
SN74LS240NSR
SOP − NS
Tape and reel
SN74LS241NSR
SN74LS244NSR
SSOP − DB
†
TOP-SIDE MARKING
SN74LS240N
SN74LS241N
SN74LS244N
SN74S240N
SN74S241N
SN74S244N
LS240
LS241
LS244
S240
S241
S244
74LS240
74LS241
74LS244
LS240
LS244
Tape and reel
SN74LS240DBR
SN74LS244DBR
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site
at www.ti.com.
‡
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54LS240, SN54LS241, SN54LS244, SN54S240, SN54S241, SN54S244
SN74LS240, SN74LS241, SN74LS244, SN74S240, SN74S241, SN74S244
OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS
SDLS144C − APRIL 1985 − REVISED MAY 2010
ORDERING INFORMATION
{
(CONTINUED)
T
A
PACKAGE
}
ORDERABLE PART NUMBER
SN54LS240J
SNJ54LS240J
SN54LS241J
SNJ54LS241J
SN54LS244J
SNJ54LS244J
CDIP − J
Tube
SN54S240J
SNJ54S240J
SN54S241J
SNJ54S241J
SN54S244J
−55°C to 125°C
55°C
SNJ54S244J
SNJ54LS240W
SNJ54LS241W
SNJ54LS244W
CFP − W
Tube
SNJ54S240W
SNJ54S241W
SNJ54S244W
SNJ54LS240FK
SNJ54LS241FK
LCCC − FK
Tube
SNJ54LS244FK
SNJ54S240FK
SNJ54S241FK
SNJ54S244FK
†
TOP-SIDE MARKING
SN54LS240J
SNJ54LS240J
SN54LS241J
SNJ54LS241J
SN54LS244J
SNJ54LS244J
SN54S240J
SNJ54S240J
SN54S241J
SNJ54S241J
SN54S244J
SNJ54S244J
SNJ54LS240W
SNJ54LS241W
SNJ54LS244W
SNJ54S240W
SNJ54S241W
SNJ54S244W
SNJ54LS240FK
SNJ54LS241FK
SNJ54LS244FK
SNJ54S240FK
SNJ54S241FK
SNJ54S244FK
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site
at www.ti.com.
‡
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
3
SN54LS240, SN54LS241, SN54LS244, SN54S240, SN54S241, SN54S244
SN74LS240, SN74LS241, SN74LS244, SN74S240, SN74S241, SN74S244
OCTAL BUFFERS AND LINE DRIVERS WITH 3-STATE OUTPUTS
SDLS144C − APRIL 1985 − REVISED MAY 2010
schematics of inputs and outputs
’LS240, ’LS241, ’LS244
EQUIVALENT OF EACH INPUT
V
CC
9 kΩ NOM
’S240, ’S241, ’S244
EQUIVALENT OF EACH INPUT
V
CC
Req
Input
Input
G and G inputs: R
eq
= 2 kΩ NOM
A inputs: R
eq
= 2.8 kΩ NOM
TYPICAL OF ALL OUTPUTS
V
CC
R
Output
GND
’LS240. ’LS241, ’LS244: R = 50
Ω
NOM
’S240, ‘S241, S244: R = 25
Ω
NOM
4
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
嵌入式系统
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