FAIRCHILD DM74ALS1240A

Revised February 2000
DM74ALS1240A
Octal 3-STATE Bus Driver
General Description
Features
These octal 3-STATE bus drivers are designed to provide
the designer with flexibility in implementing a bus interface
with memory, microprocessor, or communication systems,
and are low power dissipation versions of the
DM74ALS240A and DM74ALS241A. The output 3-STATE
gating control is organized into two separate groups of four
buffers. The DM74ALS1240A control inputs symmetrically
enable the respective outputs when set logic LOW. The 3STATE circuitry contains a feature that maintains the buffer
outputs in 3-STATE (high impedance state) during power
supply ramp-up or ramp-down. This eliminates bus glitching problems that arise during power-up and power-down.
■ Advanced oxide-isolated, ion-implanted Schottky TTL
process
■ Switching response specified into 500Ω and 50 pF load
■ Switching response specifications guaranteed over full
temperature and VCC supply range
■ PNP input design reduces input loading
■ Low power dissipation version
■ Low level drive current: 74ALS = 16 mA
Ordering Code:
Order Number
Package Number
DM74ALS1240AWM
M20B
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Logic Diagram
Function Table
Input
Output
G
A
Y
L
L
H
L
H
L
H
X
Z
H = HIGH Level Logic State
L = LOW Level Logic State
X = Don't Care (Either LOW or HIGH Level Logic State)
Z = High Impedance (OFF) State
© 2000 Fairchild Semiconductor Corporation
DS006261
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DM74ALS1240A Octal 3-STATE Bus Driver
September 1986
DM74ALS1240A
Absolute Maximum Ratings(Note 1)
Supply Voltage
7V
Input Voltage
7V
Voltage Applied to Disabled Output
5.5V
Note 1: The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
0°C to +70°C
Operating Free Air Temperature Range
−65°C to +150°C
Storage Temperature Range
Typical θJA
N Package
60.5°C/W
M Package
78.0°C/W
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Max
4.5
5
5.5
Units
VCC
Supply Voltage
VIH
HIGH Level Input Voltage
V
VIL
LOW Level Input Voltage
0.8
V
IOH
HIGH Level Output Current
−15
mA
IOL
LOW Level Output Current
16
mA
TA
Operating Free Air Temperature
70
°C
2
V
0
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise specified)
Symbol
Parameter
Conditions
Min
VIK
Input Clamp Voltage
VCC = 4.5V, II = −18 mA
VOH
HIGH Level
VCC = 4.5V to 5.5V
IOH = −0.4 mA
Output Voltage
VCC = 4.5V
IOH = −3 mA
IOH = Max
VOL
LOW Level
VCC = 4.5V
Output Voltage
II
Input Current at Maximum
Input Voltage
Typ
Max
Units
−1.2
V
VCC − 2
V
2.4
V
2
V
IOL = 12 mA
0.25
0.4
IOL = 24 mA
0.35
0.5
V
0.1
mA
VCC = 5.5V, VI = 7V
V
IIH
HIGH Level Input Current
VCC = 5.5V, VI = 2.7V
20
µA
IIL
LOW Level Input Current
VCC = 5.5V, VIL = 0.4V
−0.1
mA
IO
Output Drive Current
VCC = 5.5V, VO = 2.25V
−112
mA
IOZH
HIGH Level 3-STATE
VCC = 5.5V, VO = 2.7V
20
µA
VCC = 5.5V, VO = 0.4V
−20
µA
Output Current
IOZL
LOW Level 3-STATE
Output Current
ICC
Supply Current
VCC = 5.5V
Outputs 3-STATE
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2
−30
Outputs HIGH
5
8
mA
Outputs LOW
8
14
mA
8
13
mA
over recommended operating free air temperature range
VCC = 4.5V to 5.5V, CL = 50 pF,
Symbol
tPLH
Parameter
To
R1 = 500Ω, R2 = 500Ω,
(Input)
(Output)
TA = Min to Max
Propagation Delay Time
LOW-to-HIGH Level Output
tPHL
From
Propagation Delay Time
A
Output Enable Time
to HIGH Level Output
tPZL
Output Enable Time
G
Output Disable Time
from HIGH Level Output
tPLZ
Output Disable Time
Max
2
13
ns
2
13
ns
4
20
ns
6
22
ns
2
10
ns
3
13
ns
Y
to LOW Level Output
tPHZ
Min
Y
HIGH-to-LOW Level Output
tPZH
Units
G
Y
from LOW Level Output
3
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DM74ALS1240A
Switching Characteristics
DM74ALS1240A Octal 3-STATE Bus Driver
Physical Dimensions inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
Package Number M20B
Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
2. A critical component in any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support
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1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the
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to perform when properly used in accordance with
instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the
user.
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