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74F646 Octal Transceiver/Register with 3-STATE Outputs
March 1988
Revised January 2004
74F646
Octal Transceiver/Register with 3-STATE Outputs
General Description
These devices consist of bus transceiver circuits with
3-STATE, D-type flip-flops, and control circuitry arranged
for multiplexed transmission of data directly from the input
bus or from the internal registers. Data on the A or B bus
will be clocked into the registers as the appropriate clock
pin goes to a high logic level. Control G and direction pins
are provided to control the transceiver function. In the
transceiver mode, data present at the high impedance port
may be stored in either the A or the B register or in both.
The select controls can multiplex stored and real-time
(transparent mode) data. The direction control determines
which bus will receive data when the enable control G is
Active LOW. In the isolation mode (control G HIGH), A data
may be stored in the B register and/or B data may be
stored in the A register.
Features
s
Independent registers for A and B buses
s
Multiplexed real-time and stored data
s
74F646 has non-inverting data paths
s
3-STATE outputs
s
300 mil slim DIP
Ordering Code:
Order Number
74F646SC
74F646MSA
74F646SPC
Package Number
M24B
MSA24
N24C
Package Description
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
24-Lead Shrink Small Outline Package (SSOP), JEDEC MO-150, 5.3mm Wide
24-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
© 2004 Fairchild Semiconductor Corporation
DS009580
www.fairchildsemi.com
74F646
Unit Loading/Fan Out
Pin Names
A
0
–A
7
B
0
–B
7
CPAB, CPBA
SAB, SBA
G
DIR
Description
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
U.L.
HIGH/LOW
3.5/1.083
600/106.6 (80)
3.5/1.083
600/106.6 (80)
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
Input I
IH
/I
IL
Output I
OH
/I
OL
70
µ
A/
−
650
µ
A
−
12 mA/64 mA (48 mA)
70
µ
A/
−
650
µ
A
−
12 mA/64 mA (48 mA)
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
Function Table
Inputs
G
H
H
H
L
L
L
L
L
L
L
L
DIR
X
X
X
H
H
H
H
L
L
L
L
CPAB CPBA SAB
H or L H or L
X
X
SBA
X
X
X
X
X
X
X
L
L
H
H
Output
Input
Input
Input
Input
Data I/O (Note 1)
A
0
–A
7
B
0
–B
7
Isolation
Clock A
n
Data into A Register
Clock B
n
Data into B Register
A
n
to B
n
—Real Time (Transparent Mode)
Output Clock A
n
Data into A Register
A Register to B
n
(Stored Mode)
Clock A
n
Data into A Register and Output to B
n
B
n
to A
n
—Real Time (Transparent Mode)
Clock B
n
Data into B Register
B Register to A
n
(Stored Mode)
Clock B
n
Data into B Register and Output to A
n
X
=
Irrelevant
Function
X
X
X
X
X
X
X
L
L
H
H
X
X
X
X
X
X
X
X
X
H or L
H or L
H
=
HIGH Voltage Level
X
L
=
LOW Voltage Level
=
LOW-to-HIGH Transition
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 clock inputs.
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.
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2
74F646
Absolute Maximum Ratings
(Note 2)
Storage Temperature
Ambient Temperature under Bias
Junction Temperature under Bias
V
CC
Pin Potential to Ground Pin
Input Voltage (Note 3)
Input Current (Note 3)
Voltage Applied to Output
in HIGH State (with V
CC
=
0V)
Standard Output
3-STATE Output
Current Applied to Output
in LOW State (Max)
ESD Last Passing Voltage (Min)
twice the rated I
OL
(mA)
4000V
−
65
°
C to
+
150
°
C
−
55
°
C to
+
125
°
C
−
55
°
C to
+
150
°
C
−
0.5V to
+
7.0V
−
0.5V to
+
7.0V
−
30 mA to
+
5.0 mA
Recommended Operating
Conditions
Free Air Ambient Temperature
Supply Voltage
0
°
C to
+
70
°
C
+
4.5V to
+
5.5V
−
0.5V to V
CC
−
0.5V to
+
5.5V
Note 2:
Absolute maximum ratings are values beyond which the device
may be damaged or have its useful life impaired. Functional operation
under these conditions is not implied.
Note 3:
Either voltage limit or current limit is sufficient to protect inputs.
DC Electrical Characteristics
Symbol
V
IH
V
IL
V
CD
V
OH
V
OL
I
IH
I
BVI
I
BVIT
I
CEX
V
ID
I
OD
I
IL
I
IH
+
I
OZH
I
IL
+
I
OZL
I
OS
I
ZZ
I
CCH
I
CCL
I
CCZ
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH
Voltage
Output LOW
Voltage
Input HIGH
Current
Input HIGH Current
Breakdown Test
Input HIGH Current
Breakdown (I/O)
Output HIGH
Leakage Current
Input Leakage
Test
Output Leakage
Circuit Current
Input LOW Current
Output Leakage Current
Output Leakage Current
Output Short-Circuit Current
Bus Drainage Test
Power Supply Current
Power Supply Current
Power Supply Current
−100
4.75
3.75
−0.6
70
−650
−225
500
135
150
150
10% V
CC
10% V
CC
2.0
0.55
5.0
7.0
0.5
50
Min
2.0
0.8
−1.2
Typ
Max
Units
V
V
V
V
V
µA
µA
mA
µA
V
µA
mA
µA
µA
mA
µA
mA
mA
mA
Min
Min
Min
Max
Max
Max
Max
0.0
0.0
Max
Max
Max
Max
0.0V
Max
Max
Max
V
CC
Conditions
Recognized as a HIGH Signal
Recognized as a LOW Signal
I
IN
= −18
mA (Non I/O Pins)
I
OH
= −15
mA (A
n
, B
n
)
I
OL
=
64 mA (A
n
, B
n
)
V
IN
=
2.7V (Non I/O Pins)
V
IN
=
7.0V (Non I/O Pins)
V
IN
=
5.5V (A
n
, B
n
)
V
OUT
=
V
CC
I
ID
=
1.9
µA
All Other Pins Grounded
V
IOD
=
150 mV
All Other Pins Grounded
V
IN
=
0.5V (Non I/O Pins)
V
OUT
=
2.7V (A
n
, B
n
)
V
OUT
=
0.5V (A
n
, B
n
)
V
OUT
=
0V
V
OUT
=
5.25V
V
O
=
HIGH
V
O
=
LOW
V
O
=
HIGH Z
3
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74F646
AC Electrical Characteristics
T
A
= +25°C
Symbol
Parameter
V
CC
= +5.0V
C
L
=
50 pF
Min
f
MAX
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
t
PZH
t
PZL
t
PHZ
t
PLZ
Maximum Clock Frequency
Propagation Delay
Clock to Bus
Propagation Delay
Bus to Bus
Propagation Delay
SBA or SAB to A or B
Enable Time
OE to A or B
Disable Time
OE to A or B
Enable Time
DIR to A or B
Disable Time
DIR to A or B
90
2.0
2.0
1.0
1.0
2.0
2.0
2.0
2.0
1.0
2.0
2.0
2.0
1.0
2.0
7.0
8.0
7.0
6.5
8.5
8.0
8.5
12.0
7.5
9.0
14.0
13.0
9.0
11.0
Max
T
A
= −55°C
to
+125°C
V
CC
= +5.0V
C
L
=
50 pF
Min
75
2.0
2.0
1.0
1.0
2.0
2.0
2.0
2.0
1.0
2.0
2.0
2.0
1.0
2.0
8.5
9.5
8.0
8.0
11.0
10.0
10.0
13.5
9.0
11.0
16.0
15.0
10.0
12.0
Max
T
A
=
0°C to
+70°C
V
CC
= +5.0V
C
L
=
50 pF
Min
90
2.0
2.0
1.0
1.0
2.0
2.0
2.0
2.0
1.0
2.0
2.0
2.0
1.0
2.0
8.0
9.0
7.5
7.0
9.5
9.0
9.0
12.5
8.5
9.5
15.0
14.0
9.5
11.5
Max
MHz
ns
ns
ns
ns
ns
ns
ns
Units
AC Operating Requirements
T
A
= +25°C
Symbol
Parameter
V
CC
= +5.0V
Min
t
S
(H)
t
S
(L)
t
H
(H)
t
H
(L)
t
W
(H)
t
W
(L)
Setup Time, HIGH or LOW
Bus to Clock
Hold Time, HIGH or LOW
Bus to Clock
Clock Pulse Width
HIGH or LOW
5.0
5.0
2.0
2.0
5.0
5.0
Max
T
A
= −55°C
to
+125°C
V
CC
= +5.0V
Min
5.0
5.0
2.5
2.5
5.0
5.0
Max
T
A
=
0°C to
+70°C
V
CC
= +5.0V
Min
5.0
5.0
2.0
2.0
5.0
5.0
Max
ns
ns
ns
Units
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