74actq646 Fairchild Semiconductor, 74actq646 Datasheet - Page 2

• Manufacturer Part Number: 74actq646
• Description: 74acq646 * 74actq646 Quiet Series Octal Transceiver/registerwith 3-state Outputs
• Manufacturer: Fairchild Semiconductor

www.fairchildsemi.com
Logic Symbols
Function Table
H
L

X
Note 1: 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.
LOW Voltage Level
HIGH Voltage Level
Immaterial
LOW-to-HIGH Transition
G
H
H
H
L
L
L
L
L
L
L
L
DIR
H
H
H
H
X
X
X
L
L
L
L
CPAB CPBA
H or L H or L
H or L



X
X
X
X
X
X
Inputs
H or L



X
X
X
X
X
X
SAB
X
X
X
H
H
X
X
X
L
L
X
SBA
H
H
X
X
X
X
X
X
X
L
L
Data I/O (Note 1)
Output
A
Input
Input
0
–A
7
2
Output Clock A
B
Input
Input
0
–B
7
Isolation
Clock A
Clock B
A
A Register to B
Clock A
B
Clock B
B Register to A
Clock B
n
n
to B
to A
n
n
n
n
n
n
n
n
—Real Time (Transparent Mode)
—Real Time (Transparent Mode)
Data into A Register
Data into B Register
Data into A Register
Data into A Register and Output to B
Data into B Register
Data into B Register and Output to A
n
n
IEEE/IEC
(Stored Mode)
(Stored Mode)
Function
n
n