Page 1
TECHNICAL DATA
OCTAL BUFFER / DRIVER
WITH 3-STATE OUTPUTS
This octal buffer/driver is designed specially to
improve both the performance and density of 3-state
memory address drivers, clock drivers and busoriented receivers and transmitters. When this device is
used with the ‘ALS241, ‘AS241A, ‘ALS244 and
AS244A, the circuit designer has a choice of selected
combinations of inverting and noninverting outputs,
symmetrical active-low output-enable (OE) inputs and
complementary OE and OE inputs. This device features
high fan-out and improved fan-in.
The IN74ALS240A is characterized for operation from
0oC to 70oC.
ORDERING INFORMATION
IN74LS240AN Plastic
IN74ALS240AD SOIC
T
A
= 0° to 70° C for all
packages
Logic Symbol Logic Diagram (Positive Logic)
IN74ALS240A
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IN74ALS240A
2
ABSOLUTE MAXIMUM RATINGS
OVER OPERATING FREE-AIR TEMPERATURE RANGE
Su
pply
voltage, Vcc 7 V
Input voltage, V
I
7 V
Voltage applied to a disabled 3-state output 5.5V
Operating free-air temperature range, T
A
0oC to 70oC.
Storage temperature range-65
o
C to 150oC
RECOMMENDED OPERATING CONDITIONS
MIN NOM MAX UNIT
V
CC
Supply voltage 4.5 5 5.5 V
V
IH
High-level input voltage2V
V
IL
Low-level input voltage 0.8 V
I
OH
High-level output current -15 mA
I
OL
Low-level output current 24 mA
T
A
Operating free-air temperature 0 70
o
C
FUNCTION TABLE
INPUTS OUTPUT
OE
AY
LH L
LLH
HX Z
PIN ASSIGNMENT
Page 3
IN74ALS240A
3
ELECTRICAL CHARACTERISTICS OVER RECOMMENDED OPERATING FREEAIR TEMPERATURE RANGE
Parameter Test Conditions MIN TYP** MAX UNIT
V
IK
VCC = 4.5V II = -18mA -1.2 V
VCC = 4.5V to 5.5V I
OH
= -0.4mA VCC-2 V
V
OH
VCC = 4.5V I
OH
= -3mA 2.4 3.2 V
I
OH
= -15mA 2
V
OL
VCC = 4.5V IOL= 12 mA 0.25 0.4
I
OL
= 24 mA 0.35 0.5 V
I
OL
= 48 mA* 0.35 0.5
I
OZH
VCC = 5.5V VO= 2.7V 20
µ
A
I
OZL
VCC = 5.5V VO= 0.4V -20
µ
A
I
I
VCC = 5.5V VI = 7V 0.1 mA
I
IH
VCC = 5.5V VI = 2.7V 20
µ
A
I
IL
VCC = 5.5V VI = 0.4V -0.1
mΑ
IO*** VCC = 5.5V VO= 2.25V -30 -112
mΑ
Output high411
I
CC
VCC = 5.5V Outputs low 13 23
mΑ
Outputs disabled 14 25
*- Applies only to the -1 version and only if VCC is between 4.75V and 5.25V
**- All typical values are at V
CC
=5V, TA=25oC
***- The out put co nditions have been chosen to produce a current that closely approximates one half of the true
short-circuit output current, I
OS
SWITCHING CHARACTERISTICS
Parameter From (input) To (output)
V
CC
= 4.5 V to 5.5 V
CL = 50 pF
R
1
= 500 Ω
R2= 500 Ω
TA = MIN to MAX*
UNIT
MIN MAX
t
PLH
A Y 2 9 ns
t
PHL
2 9
t
PZH
OE Y 5 13 ns
t
PZL
5 18
t
PHZ
OE Y 2 10 ns
t
PLZ
3 12
*- For conditions shown as MIN and MAX, use the appropriate value specified under recommended operating
conditions
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