SN74LS395N データシートの表示（PDF） - Motorola => Freescale
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SN74LS395N Datasheet PDF : 6 Pages
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LOGIC DIAGRAM
S
Ds
SN 74LS395
P0
P1
P2
P3
CP
CP D
CD
Q
CP D
CD
Q
CP D
CD
Q
CP D
CD
Q
MR
OE
O0
O1
FUNCTION DESCRIPTION
The SN74LS395 contains four D-type edge-triggered
flip-flops and auxiliary gating to select a D input either from a
Parallel (Pn) input or from the preceding stage. When the
Select input is HIGH, the Pn inputs are enabled. A LOW signal
on the S input enables the serial inputs for shift-right opera-
tions, as indicated in the Truth Table.
State changes are initiated by HIGH-to-LOW transitions on
the Clock Pulse (CP) input. Signals on the Pn, Ds and S inputs
can change when the Clock is in either state, provided that the
recommended set-up and hold times are observed. When the
O2
O3 Q3
S input is LOW, a CP HIGH-LOW transition transfers data in
Q0 to Q1, Q1 to Q2, and Q2 to Q3. A left-shift is accomplished
by connecting the outputs back to the Pn inputs, but offset one
place to the left, i.e., O3 to P2, O2 to P1 and O1 to P0, with P3
acting as the linking input from another package.
When the OE input is HIGH, the output buffers are disabled
and the Q0 – Q3 outputs are in a high impedance condition.
The shifting, parallel loading or resetting operations can still be
accomplished, however.
MODE SELECT — TRUTH TABLE
Operating Mode
Asynchronous Reset
Shift, SET First Stage
Inputs @ tn
Outputs @ tn+1
MR
CP
S
Ds
Pn
O0
O1
O2
L
X
X
X
X
L
L
L
H
L
H
X
H
O0n
O1n
Shift, RESET First Stage
H
Parallel Load
H
L
L
X
L
O0n
O1n
H
X
Pn
P0
P1
P2
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
tn, n + 1 = time before and after CP HIGH-to-LOW transition
NOTE:
When OE is HIGH, outputs O0 – O3 are in the high impedance state; however, this does not affect other operations or the Q3 output.
O3
L
O2n
O2n
P3
GUARANTEED OPERATING RANGES
Symbol
Parameter
VCC
TA
IOH
IOL
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
Min
Typ
Max
Unit
4.75
5.0
5.25
V
0
25
70
°C
– 0.4
mA
8.0
mA
FAST AND LS TTL DATA
5-552
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