1/9
August 2001
s
HIGH SPEED:
t
PD
= 15 ns (TYP.) at V
CC
= 4.5V
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
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 6mA (MIN)
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 244
DESCRIPTION
The 74HCT244 is an advanced high-speed
CMOS OCTAL BUS BUFFER (3-STATE)
fabricated with silicon gate C
2
MOS technology.
G control input governs four BUS BUFFERs.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
M74HCT244
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (NON INVERTED)
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
DIP
M74HCT244B1R
SOP
M74HCT244M1R
M74HCT244RM13TR
TSSOP
M74HCT244TTR
TSSOP
DIP
SOP
M74HCT244
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
(*) 500mW at 65
C; derate to 300mW by 10mW/
C from 65
C to 85
C
RECOMMENDED OPERATING CONDITIONS
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
L
L
H
H
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
35
mA
I
CC
or I
GND
DC V
CC
or Ground Current
70
mA
P
D
Power Dissipation
500(*)
mW
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
t
r
, t
f
Input Rise and Fall Time (V
CC
= 4.5 to 5.5V)
0 to 500
ns
M74HCT244
3/9
DC SPECIFICATIONS
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, Input t
r
= t
f
= 6ns)
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
to
5.5
2.0
2.0
2.0
V
V
IL
Low Level Input
Voltage
4.5
to
5.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-20
A
4.4
4.5
4.4
4.4
V
I
O
=-6.0 mA
4.18
4.31
4.13
4.10
V
OL
Low Level Output
Voltage
4.5
I
O
=20
A
0.0
0.1
0.1
0.1
V
I
O
=6.0 mA
0.17
0.26
0.33
0.40
I
I
Input Leakage
Current
5.5
V
I
= V
CC
or GND
0.1
1
1
A
I
OZ
High Impedance
Output Leakage
Current
5.5
V
I
= V
IH
or V
IL
V
O
= V
CC
or GND
0.5
5
10
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
80
A
I
CC
Additional Worst
Case Supply
Current
5.5
Per Input pin
V
I
= 0.5V or
V
I
= 2.4V
Other Inputs at
V
CC
or GND
2.0
2.9
3.0
mA
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
C
L
(pF)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
TLH
t
THL
Output Transition
Time
4.5
50
7
12
15
18
ns
t
PLH
t
PHL
Propagation Delay
Time
4.5
50
15
22
28
33
ns
4.5
150
21
30
38
45
t
PLH
t
PHL
Propagation Delay
Time
4.5
50
15
25
31
38
ns
4.5
150
21
33
41
50
t
PZL
t
PZH
Output Enable
Time
4.5
50
R
L
= 1 K
17
30
38
45
ns
4.5
150
23
38
48
57
t
PLZ
t
PHZ
Output Disable
Time
4.5
50
R
L
= 1 K
16
30
38
45
ns
M74HCT244
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
/8 (per circuit)
TEST CIRCUIT
C
L
= 50pF/150pF or equivalent (includes jig and probe capacitance)
R
1
= 1K
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
10
10
10
pF
C
OUT
Output
Capacitance
10
pF
C
PD
Power Dissipation
Capacitance (note
1)
31
pF
TEST
SWITCH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
V
CC
t
PZH
, t
PHZ
GND
M74HCT244
5/9
WAVEFORM 1: PROPAGATION DELAY TIMES (f=1MHz; 50% duty cycle)
WAVEFORM 2 :OUTPUT AND ENABLE TIMES (f=1MHz; 50% duty cycle)
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