MC74AC646, MC74ACT646
FUNCTION TABLE
Inputs
Data I/O*
Operation or Function
G
DIR
CAB
CBA
SAB
SBA
A –A
B –B
0 7
0
7
H
H
X
X
H or L
H or L
X
X
X
X
Isolation
Store A and B Data
Input
Output
Input
Input
Input
L
L
L
L
X
X
X
X
X
X
L
H
Real Time B Data to A Bus
Stored B Data to A Bus
L
L
H
H
X
X
X
L
H
X
X
Real Time A Data to B Bus
Stored A Data to B Bus
Output
H or L
*The data output functions may be enabled or disabled by various signals at the G and DIR inputs. Data input functions are always enabled;
i.e., data at the bus pins will be stored on every LOW–to–HIGH transition of the appropriate clock inputs.
NOTE: H = HIGH Voltage Level; L = LOW Voltage Level; X = Immaterial; = LOW–to–HIGH Transition
MAXIMUM RATINGS*
Symbol
Parameter
DC Supply Voltage (Referenced to GND)
Value
Unit
V
V
CC
–0.5 to +7.0
V
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
–0.5 to V
+0.5
V
in
CC
V
out
–0.5 to V
+0.5
V
CC
I
I
I
±20
mA
mA
mA
°C
in
DC Output Sink/Source Current, per Pin
±50
±50
out
CC
DC V
or GND Current per Output Pin
Storage Temperature
CC
T
stg
–65 to +150
*MaximumRatings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recom-
mended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Min
2.0
4.5
0
Typ
5.0
5.0
–
Max
6.0
Unit
′AC
V
Supply Voltage
V
V
CC
′ACT
5.5
V , V
in out
DC Input Voltage, Output Voltage (Ref. to GND)
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
@ 3.0 V
@ 4.5 V
@ 5.5 V
@ 4.5 V
@ 5.5 V
–
150
40
25
10
8.0
–
–
Input Rise and Fall Time (Note 1)
′AC Devices except Schmitt Inputs
–
–
–
–
–
ns/V
t , t
r f
–
–
Input Rise and Fall Time (Note 2)
′ACT Devices except Schmitt Inputs
t , t
r f
ns/V
–
T
J
Junction Temperature (PDIP)
Operating Ambient Temperature Range
Output Current – High
–
140
85
°C
°C
T
A
–40
–
25
–
I
I
–24
24
mA
mA
OH
Output Current – Low
–
–
OL
1. V from 30% to 70% V ; see individual Data Sheets for devices that differ from the typical input rise and fall times.
in
CC
2. V from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.
in
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