HD74AC165/HD74ACT165
Parallel-Load 8-bit Shift Register
Description
This 8-bit serial shift register shifts data from Q
A
to Q
H
when clocked, Parallel inputs to each stage are
enabled by a low level at the Shift/Load Input. Also included is a gated clock input and a complementary
output from the eighth bit.
Clocking is accomplished through a 2-input NOR gate permitting one input to be used as a clock inhibit
function. Holding either of the clock inputs high inhibits clocking, and holding either clock input low with
the Shift/Load input high enables the other clock input. Data transfer occurs on the positive going edge of
the clock. Parallel loading is inhibited as long as the Shift/Load input is high. When taken low, data at the
parallel inputs is loaded directly into the register independent of the state of the clock.
Features
•
Outputs Source/Sink 24 mA
•
HD74ACT165 has TTL-Compatible Inputs
HD74AC165/HD74ACT165
Logic Diagram
Parallel
Inputs
A
B
C
D
E
F
G
H
Preset
Q
A
S
Clock
Q
A
R
Clear
Preset
Q
B
S
Clock
Q
B
R
Clear
Preset
Q
C
S
Clock
Q
C
R
Clear
Preset
Q
D
S
Clock
Q
D
R
Clear
Preset
Q
E
S
Clock
Q
E
R
Clear
Preset
Q
F
S
Clock
Q
F
R
Clear
Preset
Q
G
S
Clock
Q
G
R
Clear
Preset
Q
H
S
Clock
Q
H
R
Clear
Output
Q
H
Output
Q
H
S
I
S
L
CP
Clock
Inhibit
DC Characteristics
(unless otherwise specified)
Item
Maximum quiescent supply current
Maximum quiescent supply current
Maximum additional I
CC
/input
(HD74ACT165)
Symbol
I
CC
I
CC
I
CCT
Max
80
8.0
1.5
Unit
µA
µA
mA
Condition
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = Worst case
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = 25°C
V
IN
= V
CC
– 2.1 V, V
CC
= 5.5 V,
Ta = Worst case
4
HD74AC165/HD74ACT165
AC Characteristics: HD74AC165
Ta = +25°C
C
L
= 50 pF
Item
Maximum count
frequency
Propagation delay
CP to Q
H
or
Q
H
Propagation delay
CP to Q
H
or
Q
H
Propagation delay
H to Q
H
or
Q
H
Propagation delay
H to Q
H
or
Q
H
Propagation delay
S
L
to Q
H
or
Q
H
Propagation delay
S
L
to Q
H
or
Q
H
Note:
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
Symbol
f
max
V
CC
(V)*
1
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
Min
85
100
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Typ
—
—
11.0
8.0
12.0
8.5
13.5
9.5
9.0
6.5
11.5
8.5
10.0
7.5
Max
—
—
17.5
11.5
18.0
12.5
19.5
13.5
14.0
9.5
20.5
14.0
16.5
11.0
Ta = –40°C to +85°C
C
L
= 50 pF
Min
70
90
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Max
—
—
20.5
13.5
21.5
14.5
22.5
15.5
16.5
11.0
23.5
16.0
19.5
12.5
ns
ns
ns
ns
ns
ns
Unit
MHz
1. Voltage Range 3.3 is 3.3 V
±
0.3 V
Voltage Range 5.0 is 5.0 V
±
0.5 V
5
嵌入式系统
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