DM74AS373 Octal D-Type Transparent Latch with 3-STATE Outputs
April 1984
Revised March 2000
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:
Order Number
DM74AS373WM
DM74AS373N
Package Number
M20B
N20A
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 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
© 2000 Fairchild Semiconductor Corporation
DS006309
www.fairchildsemi.com
DM74AS373
Absolute Maximum Ratings
(Note 1)
Supply Voltage
Input Voltage
Voltage Applied to Disabled Output
Operating Free Air Temperature Range
Storage Temperature Range
Typical
θ
JA
N Package
M Package
52.5°C/W
70.5°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
W
t
SU
t
H
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Width of Enable Pulse, HIGH
Data Setup Time (Note 2)
Data Hold Time (Note 2)
Free Air Operating Temperature
4.5
2↓
3↓
0
70
Parameter
Min
4.5
2
0.8
−15
48
Nom
5
Max
5.5
Units
V
V
V
mA
mA
ns
ns
ns
°C
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.
Symbol
V
IK
V
OH
V
OL
I
I
I
IH
I
IL
I
O
I
OZH
I
OZL
I
CC
Parameter
Input Clamp Voltage
HIGH Level Output
Voltage
LOW Level Output Voltage
Input Current at Max Input Voltage
HIGH Level Input Current
LOW Level Input Current
Output Drive Current
OFF-State Output Current with
HIGH Level Voltage Applied
OFF-State Output Current with
LOW Level Voltage Applied
Supply Current
V
CC
=
5.5V
Outputs Open
Outputs HIGH
Outputs LOW
Outputs Disabled
55
55
65
90
85
100
mA
V
CC
=
5.5V, V
O
=
0.4V
−50
µA
Conditions
V
CC
=
4.5V, I
I
= −18
mA
V
CC
=
4.5V, I
OH
=
Max
I
OH
= −2
mA, V
CC
=
4.5V to 5.5V
V
CC
=
4.5V, I
OL
=
Max
V
CC
=
5.5V, V
IH
=
7V
V
CC
=
5.5V, V
IH
=
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
−30
2.4
V
CC
−
2
0.35
0.5
0.1
20
−0.5
−112
50
3.2
Min
Typ
Max
−1.2
Units
V
V
V
mA
µA
mA
mA
µA
3
www.fairchildsemi.com
京公网安备 11010802033920号
EEWORLD
