4-242
FAST AND LS TTL DATA
MC54/74F646
MC54/74F648
FUNCTION TABLE
Inputs
Data I/O*
Operation/Function
OE bar
DIR
CPAB
CPBA
SAB
SBA
A0–A7
Input
Input
Input
Input
B0–B7
Input
Input
Input
Input
H
H
H
H
X
X
X
X
H or L
↑
X
↑
H or L
X
↑
↑
X
X
X
X
X
X
X
X
Isolation
Store An Data in A Register
Store Bn Data in B Register
Store An/Bn Data in A/B Register
An to Bn — Real Time (Transparent Mode)
Store An Data in A Register
A Register to Bn (Stored Mode)
Clock An Data to Bn and into A Register
Bn to An — Real Time (Transparent Mode)
Store Bn Data in B Register
B Register to An (Stored Mode)
Clock An Data to Bn and into B Register
L
L
L
L
H
H
H
H
X
↑
H or L
↑
X
X
X
X
L
L
H
H
X
X
X
X
Input
Input
Input
Input
Output
Output
Output
Output
L
L
L
L
L
L
L
L
X
X
X
X
X
↑
H or L
↑
X
X
X
X
L
L
H
H
Output
Output
Output
Output
Input
Input
Input
Input
*The data output function may be enabled or disabled by various signals at the OE bar 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.
H = HIGH voltage level
L = LOW voltage level
X = Don’t Care
↑
= Low-to-High transition
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
Typ
Max
Unit
VCC
DC Supply Voltage
54, 74
4.5
5.0
5.5
V
TA
Operating Ambient Temperature Range
54
74
–55
0
25
25
125
70
°
C
IOH
Output Current
High
54
74
—
—
—
—
–12
–15
mA
IOL
Output Current
Low
54
74
—
—
—
—
48
64
mA