74ACT244
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (NON INVERTED)
February 1999
s
HIGH SPEED: t
PD
= 4.5 ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 8
A (MAX.) at T
A
= 25
o
C
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
= 24 mA (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 244
s
IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The ACT244 is an advanced CMOS OCTAL BUS
BUFFER (3-STATE) fabricated with sub-micron
silicon gate and double-layer metal wiring C
2
MOS
technology. It is ideal for low power applications
mantaining high speed operation similar to
equivalent Bipolar Schottky TTL.
G control output governs four BUS BUFFERs.
This device is desibned 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.
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES :
74ACT244B
74ACT244M
74ACT244T
M
(Micro Package)
B
(Plastic Package)
T
(TSSOP Package)
1/9
INPUT AND OUTPUT EQUIVALENT CIRCUIT
TRUTH TABLE
INPUT
OUTPUT
G
An
Yn
L
L
L
L
H
H
H
X
Z
X:"H" or "L"
Z: High impedance
PIN DESCRIPTION
PIN No
SYMBOL
NAME AND FUNCT ION
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 Enabel Input
10
GND
Ground (0V)
20
V
CC
Positive Supply Voltage
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Val ue
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
orI
GND
DC V
CC
or Ground Current
400
mA
T
stg
Storage Temperature
-65 to +150
o
C
T
L
Lead Temperature (10 sec)
300
o
C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
RECOMMENDED OPERATING CONDITIONS
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:
-40 to +85
o
C
dt/dv
Input Rise and Fall Time V
CC
= 4.5 to 5.5V (note 1)
8
ns/V
1) V
IN
from 0.8 V to 2.0 V
74ACT244
2/9
DC SPECIFICATIONS
Symb ol
Parameter
Test Co nditi ons
Valu e
Un it
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Min.
T yp.
Max.
Mi n.
Max.
V
IH
High Level Input Voltage
4.5
V
O
= 0.1 V or
V
CC
- 0.1 V
2.0
1.5
2.0
V
5.5
2.0
1.5
2.0
V
IL
Low Level Input Voltage
4.5
V
O
= 0.1 V or
V
CC
- 0.1 V
1.5
0.8
0.8
V
5.5
1.5
0.8
0.8
V
OH
High Level Output
Voltage
4.5
V
I
(*)
=
V
IH
or
V
IL
I
O
=-50
A
4.4
4.49
4.4
V
5.5
I
O
=-50
A
5.4
5.49
5.4
4.5
I
O
=-24 mA
3.86
3.76
5.5
I
O
=-24 mA
4.86
4.76
V
OL
Low Level Output
Voltage
4.5
V
I
(*)
=
V
IH
or
V
IL
I
O
=50
A
0.001
0.1
0.1
V
5.5
I
O
=50 mA
0.001
0.1
0.1
4.5
I
O
=24 mA
0.36
0.44
5.5
I
O
=24 mA
0.36
0.44
I
I
Input Leakage Current
5.5
V
I
= V
CC
orGND
0.1
1
A
I
OZ
3 State Output Leakage
Current
5.5
V
I
= V
IH
orV
IL
V
O
= V
CC
orGND
0.5
5
A
I
CCT
Max I
CC
/Input
5.5
V
I
= V
CC
-2.1V
0.6
1.5
mA
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
orGND
8
80
A
I
OLD
Dynamic Output Current
(note 1, 2)
5.5
V
OLD
= 1.65 V max
75
mA
I
OHD
V
OHD
= 3.85 V min
-75
mA
1) Maximum test duration 2ms, one output loaded attime
2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50
.
(*) All outputs loaded.
74ACT244
3/9
TEST CIRCUIT
T EST
SW IT CH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
2V
CC
t
PZH
, t
PHZ
Open
C
L
= 50 pF or equivalent (includes jigand probe capacitance)
R
L
= R
1
= 500
orequivalent
R
T
= Z
OUT
of pulse generator (typically 50
)
CAPACITIVE CHARACTERISTICS
Symb ol
Parameter
Test Co nditi ons
Valu e
Un it
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Min.
T yp.
Max.
Mi n.
Max.
C
IN
Input Capacitance
5.0
4
pF
C
i/o
I/O Capacitance
5.0
8
pF
C
PD
Power Dissipation
Capacitance (note 1)
5.0
24
pF
1) C
PD
isdefined as the value of the IC'sinternal equivalent capacitance which is calculated fromthe operating current consumption without load. (Referto
Test Circuit).Average operating current can be obtained by the following equation. I
CC
(opr) = C
PD
V
CC
f
IN
+ I
CC
/n (per circuit)
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, R
L
= 500
, Input t
r
= t
f
=3 ns)
Symb ol
Parameter
T est Con ditio n
Valu e
Un it
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Min.
T yp.
Max.
Mi n.
Max.
t
PLH
t
PHL
Propagation Delay Time
5.0
(*)
1.5
4.5
9.0
1.5
10.0
ns
t
PZL
t
PZH
Output Enable Time
5.0
(*)
1.5
5.5
9.0
1.5
10.0
ns
t
PLZ
t
PHZ
Output Disable Time
5.0
(*)
1.5
6.5
10.0
1.5
11.0
ns
(*) Voltage range is 5V
0.5V
74ACT244
4/9
WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
74ACT244
5/9
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
74ACT244
6/9
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
74ACT244
7/9
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
74ACT244
8/9
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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. Specification 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.
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