74F646_04 FAIRCHILD [Fairchild Semiconductor], 74F646_04 Datasheet - Page 2

• Manufacturer Part Number: 74F646_04
• Description: Octal Transceiver/Register with 3-STATE Outputs
• Manufacturer: FAIRCHILD [Fairchild Semiconductor]

www.fairchildsemi.com
Unit Loading/Fan Out
Function Table
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;
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
A
B
CPAB, CPBA
SAB, SBA
G
DIR
0
0
i.e., data at the bus pins will be stored on every LOW-to-HIGH transition of the clock inputs.
G
H
H
H
–A
–B
L
L
L
L
L
L
L
L
H
Pin Names
7
7
HIGH Voltage Level
DIR
X
X
X
H
H
H
H
L
L
L
L
CPAB CPBA SAB
H or L H or L
H or L



X
X
X
X
X
X
Inputs
Data Register A Inputs/
3-STATE Outputs
Data Register B Inputs/
3-STATE Outputs
Clock Pulse Inputs
Select Inputs
Output Enable Input
Direction Control Input
H or L



X
X
X
X
X
X
L
LOW Voltage Level
Description
X
X
X
H
H
X
X
X
X
L
L
SBA
X
X
X
X
X
X
X
H
H
L
L
Data I/O (Note 1)
Output
A
Input
Input
0
–A
7
2
B
Output Clock A
X
Input
Input
0
–B
Irrelevant
600/106.6 (80)
600/106.6 (80)
7
HIGH/LOW
3.5/1.083
3.5/1.083
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
Isolation
Clock B
A
A Register to B
Clock A
B
Clock B
Clock A
Clock B
B Register to A
U.L.
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
LOW-to-HIGH Transition
n
n
(Stored Mode)
(Stored Mode)
Function
12 mA/64 mA (48 mA)
12 mA/64 mA (48 mA)
Output I
70 A/ 650 A
70 A/ 650 A
20 A/ 0.6 mA
20 A/ 0.6 mA
20 A/ 0.6 mA
20 A/ 0.6 mA
Input I
IH
OH
/I
/I
IL
OL
n
n