DM74ALS874B Dual 4-Bit D-Type Edge-Triggered Flip-Flop with 3-STATE Outputs
April 1984
Revised July 2001
DM74ALS874B
Dual 4-Bit D-Type Edge-Triggered Flip-Flop
with 3-STATE Outputs
General Description
This dual 4-bit register features totem-pole 3-STATE out-
puts designed specifically for driving highly-capacitive or
relatively low-impedance loads. The high-impedance state
and increased high-logic-level drive provide this register
with the capability of being connected directly to and driv-
ing the bus lines in a bus-organized system without need
for interface or pull-up components. It is particularly attrac-
tive for implementing buffer registers, I/O ports, bidirec-
tional bus drivers, and working registers.
The eight flip-flops of the DM74ALS874B are edge-trig-
gered D-type flip-flops. On the positive transition of the
clock, the Q outputs will be set to the logic states that were
set up at the D inputs.
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 flip-flops. 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
3-STATE buffer-type outputs drive bus lines directly
s
Space saving 300 mil wide package
s
Asynchronous clear
Ordering Code:
Order Number
DM74ALS874BWM
DM74ALS874BNT
Package Number
M24B
N24C
Package Description
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
24-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
© 2001 Fairchild Semiconductor Corporation
DS006244
www.fairchildsemi.com
DM74ALS874B
Function Table
Inputs
CLR
X
L
H
H
H
D
X
X
H
L
X
CLK
X
X
OC
H
L
L
L
L
Output
Q
Z
L
H
L
Q
0
Logic Diagram
↑
↑
L
L
=
LOW State
H
=
HIGH State
X
=
Don’t Care
↑ =
Positive Edge Transition
Z
=
High Impedance State
Q
0
=
Previous Condition of Q
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2
DM74ALS874B
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
51.0
°
C/W
86.5
°
C/W
7V
7V
5.5V
0
°
C to
+
70
°
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.
−
65
°
C to
+
150
°
C
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
f
CLK
t
WCLK
t
WCLR
t
SU
t
H
t
SU
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Clock Frequency
Width of Clock Pulse
Width of Clear Pulse
Data Setup Time (Note 2)
Data Hold Time (Note 2)
Clear Inactive
Free Air Operating Temperature
HIGH
LOW
LOW
0
16.5
16.5
10
15
↑
0
↑
12
0
70
Parameter
Min
4.5
2
0.8
Nom
5
Max
5.5
Units
V
V
V
mA
mA
MHz
ns
ns
ns
ns
ns
ns
−
2.6
24
30
°
C
Note 2:
The (↑) arrow indicates the positive edge of the Clock is used for reference.
3
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DM74ALS874B
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25°C.
Symbol
Parameter
Conditions
Min
Typ
V
IK
V
OH
Input Clamp Voltage
HIGH Level
Output Voltage
V
OL
LOW Level
Output Voltage
I
I
I
IH
I
IL
I
O
I
OZH
I
OZL
I
CC
Input Current @ Maximum
Input Voltage
HIGH Level Input Current
LOW Level Input Current
Output Drive Current
OFF-State Output Current
HIGH Level Voltage Applied
OFF-State Output Current
LOW Level Voltage Applied
Supply Current
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
IH
=
2V
V
O
=
2.7V
V
CC
=
5.5V, V
IH
=
2V
V
O
=
0.4V
V
CC
=
5.5V
Outputs OPEN
Outputs HIGH
Outputs LOW
Outputs Disabled
14
19
20
−30
V
CC
=
4.5V, I
I
= −18
mA
V
CC
=
4.5V
V
IL
=
V
IL
Max
V
CC
=
4.5V to 5.5V
V
CC
=
4.5V
V
IH
=
2V
I
OL
=
24 mA
V
CC
=
5.5V, V
IH
=
7V
I
OH
= −400 µA
I
OL
=
12 mA
I
OH
=
Max
2.4
V
CC
−
2
0.25
0.35
0.4
0.5
0.1
20
−0.2
−112
20
−20
21
30
32
3.2
Max
−1.2
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
Parameter
f
MAX
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
t
PHL
Maximum Clock Frequency
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
Propagation Delay Time
HIGH-to-LOW Level Output
R
L
=
500,Ω,
C
L
=
50 pF
Conditions
From
To
Min
30
Clock
Clock
Output
Control
Output
Control
Output
Control
Output
Control
Clear
Any Q
Any Q
Any Q
Any Q
Any Q
Any Q
Any Q
4
4
4
4
2
3
5
Max
MHz
14
14
18
18
10
12
17
ns
ns
ns
ns
ns
ns
ns
Units
V
CC
=
4.5V to 5.5V
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4
DM74ALS874B
Physical Dimensions
inches (millimeters) unless otherwise noted
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
Package Number M24B
5
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