Semiconductor Components Industries, LLC, 1999
December, 1999 – Rev. 6 1Publication Order Number:
SN74LS240/D
SN74LS240 SN74LS244
Octal Buffer/Line Driver
with 3-State Outputs
The SN74LS240 and SN74LS244 are Octal Buffers and Line
Drivers designed to be employed as memory address drivers, clock
drivers and bus-oriented transmitters/receivers which provide
improved PC board density.
•Hysteresis at Inputs to Improve Noise Margins
•3-State Outputs Drive Bus Lines or Buffer Memory Address
Registers
•Input Clamp Diodes Limit High-Speed Termination Ef fects
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
VCC Supply Voltage 4.75 5.0 5.25 V
TAOperating Ambient
Temperature Range 0 25 70 °C
IOH Output Current – High –3.0 mA
–15 mA
IOL Output Current – Low 24 mA
LOW
POWER
SCHOTTKY
Device Package Shipping
ORDERING INFORMATION
SN74LS240N 16 Pin DIP 1440 Units/Box
SN74LS240DW 16 Pin
SOIC
DW SUFFIX
CASE 751D
http://onsemi.com
2500/Tape & Reel
PLASTIC
N SUFFIX
CASE 738
20
1
20
1
SN74LS244N 16 Pin DIP 1440 Units/Box
SN74LS244DW 16 Pin 2500/Tape & Reel
SN74LS240 SN74LS244
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2
LOGIC AND CONNECTION DIAGRAMS DIP (TOP VIEW)
18 17 16 15 14 13
1234567
20 19
8
VCC
1G
2G 1Y1 2A4 1Y2 1Y32A3 2A2
1A1 2Y4 1A2 2Y3 1A3 2Y2 1A4 910
2Y1 GND
12 11
1Y4 2A1
18 17 16 15 14 13
1234567
20 19
8
VCC
1G
2G 1Y1 2A4 1Y2 1Y32A3 2A2
1A1 2Y4 1A2 2Y3 1A3 2Y2 1A4 910
2Y1 GND
12 11
1Y4 2A1
SN74LS240
SN74LS244
TRUTH TABLES
SN74LS240
INPUTS
OUTPUT
1G, 2G D
OUTPUT
L
L
H
L
H
X
H
L
(Z)
SN74LS244
INPUTS
OUTPUT
1G, 2G D
OUTPUT
L
L
H
L
H
X
L
H
(Z)
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
SN74LS240 SN74LS244
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3
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol Parameter Min Typ Max Unit Test Conditions
VIH Input HIGH Voltage 2.0 VGuaranteed Input HIGH Voltage for
All Inputs
VIL Input LOW Voltage 0.8 VGuaranteed Input LOW Voltage for
All Inputs
VT+–VT– Hysteresis 0.2 0.4 V VCC = MIN
VIK Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
VO
Out
p
ut HIGH Voltage
2.4 3.4 V VCC = MIN, IOH = –3.0 mA
V
OH
O
u
tp
u
t
HIGH
Voltage
2.0 V VCC = MIN, IOH = MAX
VO
Out
p
ut LOW Voltage
0.25 0.4 V IOL = 12 mA VCC = VCC MIN,
VIN =V
IL or VIH
V
OL
O
u
tp
u
t
LOW
Voltage
0.35 0.5 V IOL = 24 mA
V
IN =
V
IL
or
V
IH
per T ruth Table
IOZH Output Off Current HIGH 20 µA VCC = MAX, VOUT = 2.7 V
IOZL Output Off Current LOW –20 µA VCC = MAX, VOUT = 0.4 V
I
In
p
ut HIGH Current
20 µA VCC = MAX, VIN = 2.7 V
I
IH
Inp
u
t
HIGH
C
u
rrent
0.1 mA VCC = MAX, VIN = 7.0 V
IIL Input LOW Current –0.2 mA VCC = MAX, VIN = 0.4 V
IOS Output Short Circuit Current (Note 1) –40 –225 mA VCC = MAX
Power Supply Current
Total, Output HIGH 27
I
Total, Output LOW LS240 44
A
V MAX
ICC LS244 46 mA VCC = MAX
Total at HIGH Z LS240 50
LS244 54
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V)
Limits
Symbol Parameter Min Typ Max Unit Test Conditions
tPLH
tPHL Propagation Delay, Data to Output
LS240 9.0
12 14
18 ns
tPLH
tPHL Propagation Delay, Data to Output
LS244 12
12 18
18 ns CL = 45 pF,
RL = 667 Ω
tPZH Output Enable Time to HIGH Level 15 23 ns
tPZL Output Enable Time to LOW Level 20 30 ns
tPLZ Output Disable T ime from LOW Level 15 25 ns CL = 5.0 pF,
tPHZ Output Disable T ime from HIGH Level 10 18 ns
L
RL = 667 Ω
SN74LS240 SN74LS244
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4
AC WAVEFORMS
1.3 V
1.3 V 1.3 V
1.3 V
1.3 V 1.3 V
1.3 V
VIN
VOUT
tPLH tPHL
1.3 V
1.3 V
VIN
VOUT SW2CL*
5 kΩ
SW1
VCC
RL
TO OUTPUT
UNDER TEST
1.3 V
tPHL tPLH
VE
VE
VOUT
VE
VE
VOUT
tPHZ
1.3 V 1.3 V
tPZL tPLZ
VOL
1.3 V
≥VOH
0.5 V
tPZH
1.3 V
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
≈1.3 V
0.5 V
≈1.3 V
SWITCH POSITIONS
Closed
Open
Closed
Closed
Open
Closed
Closed
Closed
tPZH
tPZL
tPLZ
tPHZ
SW2SW1SYMBOL
SN74LS240 SN74LS244
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5
PACKAGE DIMENSIONS
N SUFFIX
PLASTIC PACKAGE
CASE 738–03
ISSUE E
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEAD WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD
FLASH.
M
L
J20 PL M
B
M
0.25 (0.010) T
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A25.66 27.171.010 1.070
B6.10 6.600.240 0.260
C3.81 4.570.150 0.180
D0.39 0.550.015 0.022
G2.54 BSC0.100 BSC
J0.21 0.380.008 0.015
K2.80 3.550.110 0.140
L7.62 BSC0.300 BSC
M0 15 0 15
N0.51 1.010.020 0.040
____
E1.27 1.770.050 0.070
1
11
10
20
–A–
SEATING
PLANE
K
N
FG
D20 PL
–T–
M
A
M
0.25 (0.010) T
E
B
C
F1.27 BSC0.050 BSC
SN74LS240 SN74LS244
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6
D SUFFIX
PLASTIC SOIC PACKAGE
CASE 751D–05
ISSUE F
20
1
11
10
B20X
H10X
C
L
18X A1
A
SEATING
PLANE
q
hX 45
_
E
D
M
0.25 M
B
M
0.25 S
AS
B
T
eT
B
A
DIM MIN MAX
MILLIMETERS
A2.35 2.65
A1 0.10 0.25
B0.35 0.49
C0.23 0.32
D12.65 12.95
E7.40 7.60
e1.27 BSC
H10.05 10.55
h0.25 0.75
L0.50 0.90
q
0 7
NOTES:
1. DIMENSIONS ARE IN MILLIMETERS.
2. INTERPRET DIMENSIONS AND TOLERANCES
PER ASME Y14.5M, 1994.
3. DIMENSIONS D AND E DO NOT INCLUDE MOLD
PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.
5. DIMENSION B DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE PROTRUSION SHALL
BE 0.13 TOTAL IN EXCESS OF B DIMENSION AT
MAXIMUM MATERIAL CONDITION.
__
SN74LS240 SN74LS244
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7
Notes
SN74LS240 SN74LS244
http://onsemi.com
8
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SN74LS240/D
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