Philips 74als244a DATASHEETS
INTEGRATED CIRCUITS
74ALS244A/74ALS244A–1
Octal buffer (3–State)
Product specification
IC05 Data Handbook
1991 Feb 08
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
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
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