2000 Fairchild Semiconductor Corporation
DS006309
www.fairchildsemi.com
April 1984
Revised March 2000
DM74AS373 Octal
D-
T
ype T
r
anspar
ent Lat
ch
wi
th 3-ST
A
T
E
Out
puts
DM74AS373
Octal D-Type Transparent Latch with 3-STATE Outputs
General Description
These 8-bit registers feature totem-pole 3-STATE outputs
designed specifically for driving highly-capacitive or rela-
tively low-impedance loads. The high-impedance state and
increased high-logic-level drive provide these registers with
the capability of being connected directly to and driving the
bus lines in a bus-organized system without need for inter-
face or pull-up components. They are particularly attractive
for implementing buffer registers, I/O ports, bidirectional
bus drivers, and working registers.
The eight latches of the DM74AS373 are transparent D-
type latches, meaning that while the enable (G) is HIGH
the Q outputs will follow the data (D) inputs. When the
enable is taken LOW the output will be latched at the level
of the data that was set up.
A buffered output control input can be used to place the
eight outputs in either a normal logic state (HIGH or LOW
logic levels) or a high impedance state. In the high-imped-
ance state the outputs neither load nor drive the bus lines
significantly.
The output control does not affect the internal operation of
the latches. That is, the old data can be retained or new
data can be entered even while the outputs are OFF.
Features
s
Switching specifications at 50 pF
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
Functionally and pin for pin compatible with LS and ALS
TTL counterparts
s
Improved AC performance over LS and ALS TTL coun-
terparts
s
3-STATE buffer-type outputs drive bus lines directly
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code.
Connection Diagram
Order Number
Package Number
Package Description
DM74AS373WM
M20B
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
DM74AS373N
N20A
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
3
www.fairchildsemi.com
DM74AS373
Absolute Maximum Ratings
(Note 1)
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
Note 2: The (
) arrow indicates the negative edge of the enable is used for reference.
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25
C.
Supply Voltage
7V
Input Voltage
7V
Voltage Applied to Disabled Output
5.5V
Operating Free Air Temperature Range
0
C to
+
70
C
Storage Temperature Range
-
65
C to
+
150
C
Typical
JA
N Package
52.5
C/W
M Package
70.5
C/W
Symbol
Parameter
Min
Nom
Max
Units
V
CC
Supply Voltage
4.5
5
5.5
V
V
IH
HIGH Level Input Voltage
2
V
V
IL
LOW Level Input Voltage
0.8
V
I
OH
HIGH Level Output Current
-
15
mA
I
OL
LOW Level Output Current
48
mA
t
W
Width of Enable Pulse, HIGH
4.5
ns
t
SU
Data Setup Time (Note 2)
2
ns
t
H
Data Hold Time (Note 2)
3
ns
T
A
Free Air Operating Temperature
0
70
C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
IK
Input Clamp Voltage
V
CC
=
4.5V, I
I
=
-
18 mA
-
1.2
V
V
OH
HIGH Level Output
V
CC
=
4.5V, I
OH
=
Max
2.4
3.2
V
Voltage
I
OH
=
-
2 mA, V
CC
=
4.5V to 5.5V
V
CC
-
2
V
OL
LOW Level Output Voltage
V
CC
=
4.5V, I
OL
=
Max
0.35
0.5
V
I
I
Input Current at Max Input Voltage
V
CC
=
5.5V, V
IH
=
7V
0.1
mA
I
IH
HIGH Level Input Current
V
CC
=
5.5V, V
IH
=
2.7V
20
A
I
IL
LOW Level Input Current
V
CC
=
5.5V, V
IL
=
0.4V
-
0.5
mA
I
O
Output Drive Current
V
CC
=
5.5V, V
O
=
2.25V
-
30
-
112
mA
I
OZH
OFF-State Output Current with
V
CC
=
5.5V, V
O
=
2.7V
50
A
HIGH Level Voltage Applied
I
OZL
OFF-State Output Current with
V
CC
=
5.5V, V
O
=
0.4V
-
50
A
LOW Level Voltage Applied
I
CC
Supply Current
V
CC
=
5.5V
Outputs HIGH
55
90
Outputs Open
Outputs LOW
55
85
mA
Outputs Disabled
65
100
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