DM74ALS244A Octal 3-STATE Bus Driver
September 1986
Revised February 2000
DM74ALS244A
Octal 3-STATE Bus Driver
General Description
This octal 3-STATE bus driver is designed to provide the
designer with flexibility in implementing a bus interface with
memory, microprocessor, or communication systems. This
device offers 64-extended temperature Grade product
guaranteeing performance from
−40°C
to
+85°C.
The out-
put 3-STATE gating control is organized into two separate
groups of four buffers, and both control inputs enable the
respective outputs when set logic LOW. The 3-STATE cir-
cuitry contains a feature that maintains the buffer outputs in
3-STATE (high impedance state) during power supply
ramp-up or ramp-down. This eliminates bus glitching prob-
lems that arise during power-up and power-down.
Features
s
Advanced low power
Schottky TTL process
oxide-isolated
ion-implanted
s
Functional and pin compatible with the 74LS counterpart
s
Improved switching performance with less power dissi-
pation compared with the 74LS counterpart
s
Switching response specified into 500Ω and 50 pF load
s
Switching response specifications guaranteed over full
temperature and V
CC
supply range
s
PNP input design reduces input loading
Ordering Code:
Order Number
DM74ALS244AWM
DM74ALS244ASJ
DM74ALS244AMSA
DM74ALS244AN
Package Number
M20B
M20D
MSA20
N20A
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Logic Diagram
Function Table
Input
G
L
L
H
A
L
H
X
Output
Y
L
H
Z
H
=
HIGH Level Logic State
L
=
LOW Level Logic State
X
=
Don't Care (Either LOW or HIGH Level Logic State)
Z
=
High Impedance (OFF) State
© 2000 Fairchild Semiconductor Corporation
DS006212
www.fairchildsemi.com
DM74ALS244A
Absolute Maximum Ratings
(Note 1)
Supply Voltage, V
CC
Input Voltage
Voltage Applied to Disabled Output
Operating Free Air Temperature Range
Storage Temperature Range
Typical
θ
JA
N Package
M Package
60.5°C/W
79.8°C/W
7V
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
Note 1:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Operating Free-Air Temperature
0
Parameter
Min
4.5
2
0.8
−15
24
70
Typ
5
Max
5.5
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature (unless otherwise specified)
Symbol
V
IK
V
OH
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
V
OL
I
I
I
IH
I
IL
I
O
I
OZH
I
OZL
I
CC
LOW Level
Output Voltage
Input Current at Maximum Input Voltage
HIGH Level Input Current
LOW Level Input Current
Output Drive Current
HIGH Level 3-STATE Output Current
LOW Level 3-STATE Output Current
Supply Current
Conditions
V
CC
=
4.5V, I
I
= −18
mA
V
CC
=
4.5V to 5.5V
V
CC
=
4.5V
V
CC
=
4.5V
I
OL
=
24 mA
V
CC
=
5.5V, V
I
=
7V
V
CC
=
5.5V, V
I
=
2.7V
V
CC
=
5.5V, V
IL
=
0.4V
V
CC
=
5.5V, V
O
=
2.25V
V
CC
=
5.5V, V
O
=
2.7V
V
CC
=
5.5V, V
O
=
0.4V
V
CC
=
5.5V
Outputs HIGH
Outputs LOW
Outputs 3-STATE
9
15
17
−30
I
OH
= −0.4
mA
I
OH
= −3
mA
I
OH
=
Max
V
CC
−2
2.4
2
0.35
0.5
0.1
20
−0.1
−112
20
−20
15
24
27
Min
Typ
Max
−1.5
Units
V
V
V
V
V
mA
µA
mA
mA
µA
µA
mA
mA
mA
Switching Characteristics
over recommended operating free-air temperature range
Symbol
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
Parameter
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Output Enable Time to HIGH Level Output
Output Enable Time to LOW Level Output
Output Disable Time from HIGH Level Output
Output Disable Time from LOW Level Output
Conditions
V
CC
=
4.5V to 5.5V,
C
L
=
50 pF,
R1
=
500Ω,
R2
=
500Ω,
T
A
=
Min to Max
From
(Input)
A
A
G
G
G
G
To
(Output)
Y
Y
Y
Y
Y
Y
Min
3
3
3
3
2
1
Max
10
10
20
20
10
13
Units
ns
ns
ns
ns
ns
ns
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