Page 1
INTEGRATED CIRCUITS
74ALS244A/74ALS244A–1
Octal buffer (3–State)
Product specification
IC05 Data Handbook
1991 Feb 08
Page 2
Philips Semiconductors Product specification
74ALS244A/74ALS244A-1Octal buffer (3-State)
FEA TURES
•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, OE
The 74ALS244A-1 sinks 48 mA IOL if the VCC is limited to
5.0V ±0.25V.
a and OEb, each controlling four of the 3-State outputs.
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74ALS244A 4.5ns 17mA
74ALS244A-1 4.5ns 17mA
PIN CONFIGURATION
1
OEa
2
Ia0
3
Yb0
4
Ia1
5
Yb1
6
Ia2
7
Yb2
8
Ia3
9
Yb3
10 11
GND
ORDERING INFORMA TION
ORDER CODE
DESCRIPTION
20-pin plastic DIP
20-pin plastic SOL
20-pin plastic
SSOP Type II
COMMERCIAL RANGE
V
= 5V ±10%,
CC
T
= 0°C to +70°C
amb
74ALS244AN,
74ALS244A-1N
74ALS244AD,
744ALS244A-1D
74ALS244ADB,
74ALS244A-1DB
20
V
CC
19
OEb
18
Ya0
17
Ib0
16
Ya1
15
Ib1
14
Ya2
13
Ib2
12
Ya3
Ib3
SF00227
DRAWING
NUMBER
SOT146-1
SOT163-1
SOT339-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION
Ian, Ibn Data inputs 1.0/1.0 20µA/0.1mA
OEa, OEb Output Enable inputs (active-Low) 1.0/1.0 20µA/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: 20µA in the High state and 0.1mA in the Low state.
LOGIC SYMBOL
1
OEa
OEb19
V
= Pin 20
CC
GND = Pin 10
2 4 6 8 17 15 13 11
Ia0 Ia1 Ia2 Ia3 Ib0 Ib1 Ib2 Ib3
Ya0 Ya1 Ya2 Ya3 Yb0 Yb1 Yb2 Yb3
18 16 14 12 3 5 7 9
SF00228
IEC/IEEE SYMBOL
74ALS (U.L.)
HIGH/LOW
1
19
2
4
6
8
17
15
13
11
EN1
EN2
2D
1
2
LOAD VALUE
HIGH/LOW
18
16
14
12
3
5
7
9
SF00229
1991 Feb 08 853–1277 01670
2
Page 3
Philips Semiconductors Product specification
I
Current applied to output in Low output state
SYMBOL
UNIT
IOLLow-level output current
74ALS244A/74ALS244A-1Octal buffer (3-State)
LOGIC DIAGRAM
2
Ia0
4
Ia1
6
Ia2
18
Ya0
16
Ya1
14
Ya2
Ib0
Ib1
Ib2
17
15
13
3
Yb0
5
Yb1
7
Yb2
FUNCTION TABLE
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
Ia3
OEa
V
= Pin 20
CC
GND = Pin 10
8
1
12
Ya3
Ib3
OE
11
19
b
9
Yb3
L = Low voltage level
X = Don’t care
Z = High impedance “off” state
SF00230
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
V
CC
V
IN
I
IN
V
OUT
OUT
T
amb
T
stg
Supply voltage –0.5 to +7.0 V
Input voltage –0.5 to +7.0 V
Input current –30 to +5 mA
Voltage applied to output in High output state –0.5 to V
pp
p
Operating free-air temperature range 0 to +70 °C
Storage temperature range –65 to +150 °C
PARAMETER RATING UNIT
p
All versions 48 mA
-1 version 96 mA
INPUTS OUTPUTS
CC
V
RECOMMENDED OPERATING CONDITIONS
PARAMETER
V
CC
V
V
I
IK
I
OH
T
amb
NOTES:
1. The 48mA limit applies only under the condition of V
Supply voltage 4.5 5.0 5.5 V
High-level input voltage 2.0 V
IH
Low-level input voltage 0.8 V
IL
Input clamp current –18 mA
High-level output current –15 mA
p
Operating free-air temperature range
CC
= 5.0V ± 5%.
LIMITS
MIN NOM MAX
All versions 24 mA
-1 versions 48
1
mA
0 +70 °C
1991 Feb 08
3
Page 4
Philips Semiconductors Product specification
SYMBOL
PARAMETER
TEST CONDITIONS
1
UNIT
CC
,
IL
,
VOHHigh level out ut voltage
All versions
CC
,
IL
,
VOLLow level out ut voltage
74ALS244A/74ALS244A-1Octal buffer (3-State)
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
LIMITS
MIN TYP
– 2 V
CC
V
I
OZH
I
I
I
I
IH
I
IL
OZL
I
O
CC
VCC±10%, VIL = MAX,
-
p
VIH = MIN
VCC = MIN, VIL = MAX,
V
= MIN
IH
VCC = MIN, VIL = MAX,
-
p
-1 version
Input clamp voltage VCC = MIN, II = I
IK
Input current at maximum input voltage VCC = MAX, VI = 7.0V 0.1 mA
I
VIH = MIN
VCC = 4.75V, VIL = MAX,
V
= MIN
IH
IK
IOH = –0.4mA V
IOH = –3mA 2.4 3.2 V
IOH = –15mA 2.0 V
I
= 12mA 0.25 0.40 V
OL
I
= 24mA 0.35 0.50 V
OL
I
= 48mA 0.35 0.50 V
OL
High-level input current VCC = MAX, VI = 2.7V 20 µA
Low-level input current VCC = MAX, VI = 0.4V –0.1 mA
Off-state output current,
High-level voltage applied
Off-state output current,
Low-level voltage applied
Output current
3
Supply current (total)
I
CCH
I
CCL
I
CCZ
VCC = MAX, VI = 2.7V 20 µA
VCC = MAX, VI = 0.4V –20 µA
VCC = MAX, VO = 2.25V –30 –112 mA
VCC = MAX
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
3. The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, I
= 5V, T
CC
amb
= 25°C.
2
MAX
–0.73 –1.5 V
6.5 15 mA
19.5 24 mA
25 30 mA
OS
.
AC ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER TEST CONDITION
1991 Feb 08
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
Propagation delay
In to Yn
Output enable time
to High or Low level
Output disable time
from High or Low level
LIMITS
T
= 0°C to +70°C
amb
V
= +5.0V ± 10%
CC
C
= 50pF, RL = 500Ω
L
UNIT
MIN MAX
Waveform 1
Waveform 2
Waveform 3
Waveform 2
Waveform 3
1.5
1.5
1.0
2.5
2.5
2.5
10.0
10.0
10.0
12.0
10.0
12.0
ns
ns
ns
4
Page 5
Philips Semiconductors Product specification
74ALS244A/74ALS244A-1Octal buffer (3-State)
AC WAVEFORMS
For all waveforms, VM = 1.3V.
Ian, Ibn
Yn
V
M
t
PLH
V
M
t
PHL
V
M
V
M
Waveform 1. Propagation Delay for Non-inverting Outputs
OEn
V
M
t
PZH
Yn
V
M
t
PHZ
V
M
VOH–0.3V
Waveform 2. 3-State Output Enable Time to High Level
and Output Disable Time from High Level
TEST CIRCUIT AND WAVEFORMS
SF00231
0V
SF00233
OEn
V
M
t
PZL
Yn
V
M
t
PLZ
V
M
VOL+0.3V
SF00234
Waveform 3. 3-State Output Enable Time to Low Level
and Output Disable Time from Low Level
3.5V
V
PULSE
GENERATOR
CC
V
IN
R
T
D.U.T.
V
OUT
R
L
C
R
L
L
7.0V
Test Circuit for 3-State Outputs
SWITCH POSITION
TEST SWITCH
t
PLZ
, t
PZL
closed
All other open
DEFINITIONS:
R
= Load resistor;
L
see AC electrical characteristics for value.
CL= Load capacitance includes jig and probe capacitance;
see AC electrical characteristics for value.
R
= T ermination resistance should be equal to Z
T
pulse generators.
OUT
of
NEGATIVE
PULSE
POSITIVE
PULSE
Family
74ALS
90%
10%
Amplitude
t
w
V
M
10%
)
t
f
THL (tf
t
)
TLH (tr
90%
V
M
t
TLH (tr
t
THL (tf
t
w
Input Pulse Definition
INPUT PULSE REQUIREMENTS
V
Rep.Rate
M
3.5V
1.3V
1MHz
V
10%
)
)
90%
t
w
500ns
M
V
M
t
TLHtTHL
2.0ns 2.0ns
90%
10%
AMP (V)
0.3V
AMP (V)
0.3V
SC00072
1991 Feb 08
5
Page 6
Philips Semiconductors Product specification
74ALS244A/74ALS244–1Octal buffer (3–State)
DIP20: plastic dual in-line package; 20 leads (300 mil) SOT146-1
1991 Feb 08
6
Page 7
Philips Semiconductors Product specification
74ALS244A/74ALS244–1Octal buffer (3–State)
SO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1
1991 Feb 08
7
Page 8
Philips Semiconductors Product specification
74ALS244A/74ALS244–1Octal buffer (3–State)
SSOP20: plastic shrink small outline package; 20 leads; body width 5.3 mm SOT339-1
1991 Feb 08
8
Page 9
Philips Semiconductors Product specification
74ALS244A/74ALS244–1Octal buffer (3–State)
DEFINITIONS
Data Sheet Identification Product Status Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICA TIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.
1991 Feb 08
9
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