MC74AC646, MC74ACT646
FUNCTION TABLE
Inputs
G
H
H
L
L
L
L
DIR
X
X
L
L
H
H
CAB
H or L
X
X
X
H or L
CBA
H or L
X
X
X
X
SAB
X
X
X
X
L
H
SBA
X
X
L
H
X
X
A0–A7
Input
Output
Input
Data I/O*
Operation or Function
F nction
B0–B7
Input
Input
Output
Isolation
Store A and B Data
Real Time B Data to A Bus
Stored B Data to A Bus
Real Time A Data to B Bus
Stored A Data to B Bus
*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
VCC
Vin
Vout
Iin
Iout
ICC
Tstg
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Sink/Source Current, per Pin
DC VCC or GND Current per Output Pin
Storage Temperature
Value
–0.5 to +7.0
–0.5 to VCC +0.5
–0.5 to VCC +0.5
±20
±50
±50
–65 to +150
Unit
V
V
V
mA
mA
mA
°C
*Maximum Ratings 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
VCC
Vin, Vout
Supply Voltage
DC Input Voltage, Output Voltage (Ref. to GND)
VCC @ 3.0 V
tr, tf
Input Rise and Fall Time (Note 1)
′AC
Devices except Schmitt Inputs
VCC @ 4.5 V
VCC @ 5.5 V
tr, tf
TJ
TA
IOH
IOL
In ut
Input Rise and Fall Time (Note 2)
′ACT
Devices except Schmitt Inputs
Junction Temperature (PDIP)
Operating Ambient Temperature Range
Output Current – High
Output Current – Low
VCC @ 4.5 V
VCC @ 5.5 V
Parameter
′AC
′ACT
Min
2.0
4.5
0
–
–
–
–
–
–
–40
–
–
Typ
5.0
5.0
–
150
40
25
10
8.0
–
25
–
–
Max
6.0
5.5
VCC
–
–
–
–
ns/V
–
140
85
–24
24
°C
°C
mA
mA
ns/V
V
V
Unit
1. Vin from 30% to 70% VCC; see individual Data Sheets for devices that differ from the typical input rise and fall times.
2. Vin from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.
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