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April 2001
s
HIGH SPEED: t
PD
= 5ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A(MAX.) at T
A
=25C
s
COMPATIBLE WITH TTL OUTPUTS
V
IH
= 2V (MIN.), V
IL
= 0.8V (MAX.)
s
50
TRANSMISSION LINE DRIVING
CAPABILITY
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 24mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 4.5V to 5.5V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 240
s
IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The 74ACT240 is an advanced high-speed CMOS
OCTAL BUS BUFFER (3-STATE) fabricated with
sub-micron silicon gate and double-layer metal
wiring C
2
MOS tecnology.
G control output governs four BUS BUFFERs.
This device is designed to be used with 3 state
memory address drivers, etc.
The device is designed to interface directly High
Speed CMOS systems with TTL, NMOS and
CMOS output voltage levels.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
74ACT240
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (INVERTED)
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
DIP
74ACT240B
SOP
74ACT240M
74ACT240MTR
TSSOP
74ACT240TTR
TSSOP
DIP
SOP
74ACT240
2/9
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
TRUTH TABLE
X : Don't Care
Z : High Impedance
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied.
RECOMMENDED OPERATING CONDITIONS
1) V
IN
from 0.8V to 2.0V
PIN No
SYMBOL
NAME AND FUNCTION
1
1G
Output Enable Input
2, 4, 6, 8
1A1 to 1A4
Data Inputs
9, 7, 5, 3
2Y1 to 2Y4
Data Outputs
11, 13, 15,
17
2A1 to 2A4
Data Inputs
18, 16, 14,
12
1Y1 to 1Y4
Data Outputs
19
2G
Output Enable Input
10
GND
Ground (0V)
20
V
CC
Positive Supply Voltage
INPUTS
OUTPUT
G
An
Yn
L
L
H
L
H
L
H
X
Z
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7
V
V
I
DC Input Voltage
-0.5 to V
CC
+ 0.5
V
V
O
DC Output Voltage
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
50
mA
I
CC
or I
GND
DC V
CC
or Ground Current
400
mA
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to V
CC
V
V
O
Output Voltage
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
dt/dv
Input Rise and Fall Time V
CC
= 4.5 to 5.5V (note 1)
8
ns/V
74ACT240
3/9
DC SPECIFICATIONS
1) Maximum test duration 2ms, one output loaded at time
2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, R
L
= 500
, Input t
r
= t
f
= 3ns)
(*) Voltage range is 5.0V
0.5V
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
4.5
V
O
= 0.1 V or
V
CC
-0.1V
2.0
1.5
2.0
2.0
V
5.5
2.0
1.5
2.0
2.0
V
IL
Low Level Input
Voltage
4.5
V
O
= 0.1 V or
V
CC
-0.1V
1.5
0.8
0.8
0.8
5.5
1.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-50
A
4.4
4.49
4.4
4.4
5.5
I
O
=-50
A
5.4
5.49
5.4
5.4
4.5
I
O
=-24 mA
3.86
3.76
3.7
V
5.5
I
O
=-24 mA
4.86
4.76
4.7
V
OL
Low Level Output
Voltage
4.5
I
O
=50
A
0.001
0.1
0.1
0.1
5.5
I
O
=50
A
0.001
0.1
0.1
0.1
4.5
I
O
=24 mA
0.36
0.44
0.5
5.5
I
O
=24 mA
0.36
0.44
0.5
I
I
Input Leakage Cur-
rent
5.5
V
I
= V
CC
or GND
0.1
1
1
A
I
OZ
High Impedance
Output Leakege
Current
5.5
V
I
= V
IH
or V
IL
V
O
= V
CC
or GND
0.5
5
5
mA
I
CCT
Max I
CC
/Input
5.5
V
I
= V
CC
- 2.1V
0.6
1.5
1.6
mA
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
80
A
I
OLD
Dynamic Output
Current (note 1, 2)
5.5
V
OLD
= 1.65 V max
75
50
mA
I
OHD
V
OHD
= 3.85 V min
-75
-50
mA
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
PLH
t
PHL
Propagation Delay
Time
5.0
(*)
1.5
5.0
7.5
1.5
8.5
1.5
8.5
ns
t
PZL
t
PZH
Output Enable
Time
5.0
(*)
1.5
6.0
8.5
1.5
9.5
1.5
9.5
ns
t
PLZ
t
PHZ
Output Disable
Time
5.0
(*)
1.5
6.5
10.0
1.5
10.5
1.5
10.5
ns
74ACT240
4/9
CAPACITIVE CHARACTERISTICS
1) C
PD
is defined as the value of the IC's internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/n (per circuit)
TEST CIRCUIT
C
L
= 50pF or equivalent (includes jig and probe capacitance)
R
L
= R
1
= 500
or equivalent
R
T
= Z
OUT
of pulse generator (typically 50
)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
5.0
4
pF
C
OUT
Output
Capacitance
5.0
8
pF
C
PD
Power Dissipation
Capacitance (note
1)
5.0
f
IN
= 10MHz
21
pF
TEST
SWITCH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
2V
CC
t
PZH
, t
PHZ
Open
74ACT240
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WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
74ACT240
6/9
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
a1
0.254
0.010
B
1.39
1.65
0.055
0.065
b
0.45
0.018
b1
0.25
0.010
D
25.4
1.000
E
8.5
0.335
e
2.54
0.100
e3
22.86
0.900
F
7.1
0.280
I
3.93
0.155
L
3.3
0.130
Z
1.34
0.053
P001J
Plastic DIP-20 (0.25) MECHANICAL DATA
74ACT240
7/9
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
2.65
0.104
a1
0.10
0.20
0.004
0.007
a2
2.45
0.096
b
0.35
0.49
0.013
0.019
b1
0.23
0.32
0.009
0.012
C
0.50
0.020
c1
45 (typ.)
D
12.60
13.00
0.496
0.512
E
10.00
10.65
0.393
0.419
e
1.27
0.050
e3
11.43
0.450
F
7.40
7.60
0.291
0.299
L
0.50
1.27
0.19
0.050
M
0.75
0.029
S
8 (max.)
P013L
SO-20 MECHANICAL DATA
74ACT240
8/9
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
1.1
0.433
A1
0.05
0.10
0.15
0.002
0.004
0.006
A2
0.85
0.9
0.95
0.335
0.354
0.374
b
0.19
0.30
0.0075
0.0118
c
0.09
0.2
0.0035
0.0079
D
6.4
6.5
6.6
0.252
0.256
0.260
E
6.25
6.4
6.5
0.246
0.252
0.256
E1
4.3
4.4
4.48
0.169
0.173
0.176
e
0.65 BSC
0.0256 BSC
K
0
o
4
o
8
o
0
o
4
o
8
o
L
0.50
0.60
0.70
0.020
0.024
0.028
c
E
b
A2
A
E1
D
1
PIN 1 IDENTIFICATION
A1
L
K
e
TSSOP20 MECHANICAL DATA
74ACT240
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
2001 STMicroelectronics - Printed in Italy - All Rights Reserved
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