Philips
Semiconductors
74ALS244A/74ALS244A1
Octal buffer (3State)
Product specification
IC05 Data Handbook
1991 Feb 08
INTEGRATED CIRCUITS
Philips Semiconductors
Product specification
74ALS244A/74ALS244A-1
Octal buffer (3-State)
2
1991 Feb 08
8531277 01670
FEATURES
Octal bus interface
3-State buffer outputs sink 24mA and source 15mA
The -1 version sinks 48mA
DESCRIPTION
The 74ALS244A is an octal buffer that is ideal for driving bus lines or
buffer memory address registers. The outputs are all capable of
sinking 24mA and sourcing up to 15mA, producing very good
capacitive drive characteristics. The device features two output
enables, OEa and OEb, each controlling four of the 3-State outputs.
The 74ALS244A-1 sinks 48 mA I
OL
if the V
CC
is limited to
5.0V
0.25V.
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74ALS244A
4.5ns
17mA
74ALS244A-1
4.5ns
17mA
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20 VCC
OEa
Ia0
Yb0
Ia1
Yb1
Ia2
Yb2
Ia3
Yb3
GND
SF00227
OEb
Ya0
Ib0
Ya1
Ib1
Ya2
Ib2
Ya3
Ib3
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V
10%,
T
amb
= 0
C to +70
C
DRAWING
NUMBER
20-pin plastic DIP
74ALS244AN,
74ALS244A-1N
SOT146-1
20-pin plastic SOL
74ALS244AD,
744ALS244A-1D
SOT163-1
20-pin plastic
SSOP Type II
74ALS244ADB,
74ALS244A-1DB
SOT339-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74ALS (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
Ian, Ibn
Data inputs
1.0/1.0
20
A/0.1mA
OEa, OEb
Output Enable inputs (active-Low)
1.0/1.0
20
A/0.1mA
Yan, Ybn
Data outputs
750/240
15mA/24mA
Yan, Ybn
Data outputs (-1 version)
750/480
15mA/48mA
NOTE:
One (1.0) ALS unit load is defined as: 20
A in the High state and 0.1mA in the Low state.
LOGIC SYMBOL
OEa
1
SF00228
2
4
6
8
17
15
13
11
18
16
14
12
3
5
7
9
Ia0
Ia1
Ia2
Ia3
Ib0
Ib1
Ib2
Ib3
Ya0
Ya1 Ya2
Ya3 Yb0 Yb1 Yb2 Yb3
VCC = Pin 20
GND = Pin 10
OEb
19
IEC/IEEE SYMBOL
1
2D
EN1
EN2
1
2
19
2
4
6
8
17
15
13
11
18
16
14
12
3
5
7
9
SF00229
Philips Semiconductors
Product specification
74ALS244A/74ALS244A-1
Octal buffer (3-State)
1991 Feb 08
3
LOGIC DIAGRAM
VCC
=
Pin 20
Ia0
SF00230
OEa
Ia3
Ia2
Ia1
2
4
6
8
1
Ya0
Ya1
Ya2
Ya3
18
16
14
12
Ib0
Ib1
Ib2
Ib3
OEb
17
15
13
11
19
3
5
7
9
Yb0
Yb1
Yb2
Yb3
GND = Pin 10
FUNCTION TABLE
INPUTS
OUTPUTS
OEa
Ia
OEb
Ib
Ya
Yb
L
L
L
L
L
L
L
H
L
H
H
H
H
X
H
X
Z
Z
H = High voltage level
L
= Low voltage level
X = Don't care
Z = High impedance "off" state
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limit set forth in this table may impair the useful life of the device.
Unless otherwise noted these limits are over the operating free air temperature range.)
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Supply voltage
0.5 to +7.0
V
V
IN
Input voltage
0.5 to +7.0
V
I
IN
Input current
30 to +5
mA
V
OUT
Voltage applied to output in High output state
0.5 to V
CC
V
I
O
Current applied to output in Low output state
All versions
48
mA
I
OUT
Current applied to output in Low output state
-1 version
96
mA
T
amb
Operating free-air temperature range
0 to +70
C
T
stg
Storage temperature range
65 to +150
C
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
LIMITS
UNIT
SYMBOL
PARAMETER
MIN
NOM
MAX
UNIT
V
CC
Supply voltage
4.5
5.0
5.5
V
V
IH
High-level input voltage
2.0
V
V
IL
Low-level input voltage
0.8
V
I
IK
Input clamp current
18
mA
I
OH
High-level output current
15
mA
I
O
Low level output current
All versions
24
mA
I
OL
Low-level output current
-1 versions
48
1
mA
T
amb
Operating free-air temperature range
0
+70
C
NOTES:
1. The 48mA limit applies only under the condition of V
CC
= 5.0V
5%.
Philips Semiconductors
Product specification
74ALS244A/74ALS244A-1
Octal buffer (3-State)
1991 Feb 08
4
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
SYMBOL
PARAMETER
TEST CONDITIONS
1
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITIONS
1
MIN
TYP
2
MAX
UNIT
V
CC
10%, V
IL
= MAX,
I
OH
= 0.4mA
V
CC
2
V
V
OH
High-level output voltage
CC
,
IL
,
V
IH
= MIN
I
OH
= 3mA
2.4
3.2
V
V
OH
High level out ut voltage
V
CC
= MIN, V
IL
= MAX,
V
IH
= MIN
I
OH
= 15mA
2.0
V
All versions
V
CC
= MIN, V
IL
= MAX,
I
OL
= 12mA
0.25
0.40
V
V
OL
Low-level output voltage
All versions
CC
,
IL
,
V
IH
= MIN
I
OL
= 24mA
0.35
0.50
V
V
OL
Low level out ut voltage
-1 version
V
CC
= 4.75V, V
IL
= MAX,
V
IH
= MIN
I
OL
= 48mA
0.35
0.50
V
V
IK
Input clamp voltage
V
CC
= MIN, I
I
= I
IK
0.73
1.5
V
I
I
Input current at maximum input voltage
V
CC
= MAX, V
I
= 7.0V
0.1
mA
I
IH
High-level input current
V
CC
= MAX, V
I
= 2.7V
20
A
I
IL
Low-level input current
V
CC
= MAX, V
I
= 0.4V
0.1
mA
I
OZH
Off-state output current,
High-level voltage applied
V
CC
= MAX, V
I
= 2.7V
20
A
I
OZL
Off-state output current,
Low-level voltage applied
V
CC
= MAX, V
I
= 0.4V
20
A
I
O
Output current
3
V
CC
= MAX, V
O
= 2.25V
30
112
mA
I
CCH
6.5
15
mA
I
CC
Supply current (total)
I
CCL
V
CC
= MAX
19.5
24
mA
I
CCZ
25
30
mA
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable type.
2. All typical values are at V
CC
= 5V, T
amb
= 25
C.
3. The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, I
OS
.
AC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL
PARAMETER
TEST CONDITION
T
amb
= 0
C to +70
C
V
CC
= +5.0V
10%
C
L
= 50pF, R
L
= 500
UNIT
MIN
MAX
t
PLH
t
PHL
Propagation delay
In to Yn
Waveform 1
1.5
1.5
10.0
10.0
ns
t
PZH
t
PZL
Output enable time
to High or Low level
Waveform 2
Waveform 3
1.0
2.5
10.0
12.0
ns
t
PHZ
t
PLZ
Output disable time
from High or Low level
Waveform 2
Waveform 3
2.5
2.5
10.0
12.0
ns
Philips Semiconductors
Product specification
74ALS244A/74ALS244A-1
Octal buffer (3-State)
1991 Feb 08
5
AC WAVEFORMS
For all waveforms, V
M
= 1.3V.
V
M
V
M
V
M
V
M
Yn
Ian, Ibn
t
PLH
t
PHL
SF00231
Waveform 1.
Propagation Delay for Non-inverting Outputs
V
OH
0.3V
V
M
V
M
V
M
Yn
t
PZH
t
PHZ
SF00233
OEn
0V
Waveform 2.
3-State Output Enable Time to High Level
and Output Disable Time from High Level
V
OL
+0.3V
V
M
V
M
V
M
Yn
t
PZL
t
PLZ
SF00234
OEn
3.5V
Waveform 3.
3-State Output Enable Time to Low Level
and Output Disable Time from Low Level
TEST CIRCUIT AND WAVEFORMS
tw
90%
VM
10%
90%
VM
10%
90%
VM
10%
90%
VM
10%
NEGATIVE
PULSE
POSITIVE
PULSE
tw
AMP (V)
0.3V
0.3V
tTHL (tf
f
)
INPUT PULSE REQUIREMENTS
Rep.Rate
t
w
t
TLH
t
THL
1MHz
500ns
2.0ns
2.0ns
Input Pulse Definition
VCC
Family
74ALS
D.U.T.
PULSE
GENERATOR
RL
CL
RT
VIN
VOUT
Test Circuit for 3-State Outputs
DEFINITIONS:
R
L
= Load resistor;
see AC electrical characteristics for value.
C
L
= Load capacitance includes jig and probe capacitance;
see AC electrical characteristics for value.
R
T
= Termination resistance should be equal to Z
OUT
of
pulse generators.
tTHL (tf
)
tTLH (tr
)
tTLH (tr
)
AMP (V)
Amplitude
3.5V
1.3V
V
M
SC00072
RL
7.0V
SWITCH POSITION
TEST
SWITCH
t
PLZ
, t
PZL
closed
All other
open
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