The data output functions may be enabled or disabled by various signals at OEAB or OEBA inputs. Data input functions are always enabled, i.e.,
data at the bus pins will be stored on every LOW-to-HIGH transition on the clock inputs. This also applies to data I/O (A and B: 8–15) and #2 control pins.
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2
74LCX16652
Functional Description
In the transceiver mode, data present at the HIGH imped-
ance port may be stored in either the A or B register or
both.
The select (SAB
n
, SBA
n
) controls can multiplex stored and
real-time.
The examples below demonstrate the four fundamental
bus-management functions that can be performed with the
74LCX16652.
Data on the A or B data bus, or both can be stored in the
internal D flip-flop by LOW-to-HIGH transitions at the
appropriate Clock Inputs (CPAB
n
, CPBA
n
) regardless of
the Select or Output Enable Inputs. When SAB and SBA
are in the real time transfer mode, it is also possible to
store data without using the internal D flip-flops by simulta-
neously enabling OEAB
n
and OEBA
n
. In this configuration
each Output reinforces its Input. Thus when all other data
sources to the two sets of bus lines are in a HIGH imped-
ance state, each set of bus lines will remain at its last state.
Real-Time
Transfer Bus B to Bus A
Real-Time
Transfer Bus A to Bus B
OEAB
1
OEBA
1
CPAB
1
CPBA
1
SAB
1
SBA
1
L
L
X
X
X
L
OEAB
1
OEBA
1
CPAB
1
CPBA
1
SAB
1
SBA
1
H
H
X
X
L
X
Transfer Storage
Data to A or B
Storage
OEAB
1
OEBA
1
CPAB
1
CPBA
1
SAB
1
SBA
1
H
L
H or L
H or L
H
H
OEAB
1
OEBA
1
CPAB
1
CPBA
1
SAB
1
SBA
1
X
L
L
H
X
H
X
X
X
X
X
X
X
X
3
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74LCX16652
Logic Diagram
Please note that these diagrams are provided only for the understanding of logic operations and should not be used to estimate propagation delays.
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4
74LCX16652
Absolute Maximum Ratings
(Note 3)
Symbol
V
CC
V
I
V
O
I
IK
I
OK
I
O
I
CC
I
GND
T
STG
Parameter
Supply Voltage
DC Input Voltage
DC Output Voltage
DC Input Diode Current
DC Output Diode Current
DC Output Source/Sink Current
DC Supply Current per Supply Pin
DC Ground Current per Ground Pin
Storage Temperature
Value
Conditions
Units
V
V
Output in 3-STATE
Output in HIGH or LOW State (Note 4)
V
I
<
GND
V
O
<
GND
V
O
>
V
CC
V
mA
mA
mA
mA
mA
−
0.5 to
+
7.0
−
0.5 to
+
7.0
−
0.5 to
+
7.0
−
0.5 to V
CC
+
0.5
−
50
−
50
+
50
±
50
±
100
±
100
−
65 to
+
150
°
C
Recommended Operating Conditions
(Note 5)
Symbol
V
CC
V
I
V
O
I
OH
/I
OL
Supply Voltage
Input Voltage
Output Voltage
Output Current
HIGH or LOW State
3-STATE
V
CC
=
3.0V
−
3.6V
V
CC
=
2.7V
−
3.0V
V
CC
=
2.3V
−
2.7V
T
A
Free-Air Operating Temperature
Input Edge Rate, V
IN
=
0.8V–2.0V, V
CC
=
3.0V
Parameter
Operating
Data Retention
Min
2.0
1.5
0
0
0
Max
3.6
3.6
5.5
V
CC
5.5
Units
V
V
V
±
24
±
12
±
8
−
40
0
85
10
mA
°
C
ns/V
∆
t/
∆
V
Note 3:
The Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated
at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the Absolute Maximum Ratings. The “Recom-
mended Operating Conditions” table will define the conditions for actual device operation.
Note 4:
I
O
Absolute Maximum Rating must be observed.
Note 5:
Unused (inputs or I/O's) must be held HIGH or LOW. They may not float.
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