74VHC245 Octal Bidirectional Transceiver with 3-STATE Outputs
November 1992
Revised March 1999
74VHC245
Octal Bidirectional Transceiver with 3-STATE Outputs
General Description
The VHC245 is an advanced high speed CMOS octal bus
transceiver fabricated with silicon gate CMOS technology.
It achieves high speed operation similar to equivalent Bipo-
lar Schottky TTL while maintaining the CMOS low power
dissipation. The VHC245 is intended for bidirectional asyn-
chronous communication between data busses. The direc-
tion of data transmission is determined by the level of the
T/R input. The enable input can be used to disable the
device so that the busses are effectively isolated. All inputs
are equipped with protection circuits against static dis-
charge.
Features
s
High Speed: t
PD
=
4.0 ns (typ) at V
CC
=
5V
s
High Noise Immunity: V
NIH
=
V
NIL
=
28% V
CC
(Min)
s
Power Down Protection is provided on all inputs
s
Low Noise: V
OLP
=
0.9V (typ)
s
Low Power Dissipation:
I
CC
=
4
µA
(Max) @ T
A
=
25°C
s
Pin and Function Compatible with 74HC245
Ordering Code:
Order Number
74VHC245M
74VHC245SJ
74VHC245MTC
74VHC245N
Package Number
M20B
M20D
MTC20
N20A
Package Description
20-Lead Small Outline Integrated Package (SOIC), JEDEC MS-013, 0.300” Wide
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Surface mount packages are also available on Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Symbol
IEEE/IEC
Connection Diagram
Pin Description
Pin
Names
OE
T/R
A
0
–A
7
B
0
–B
7
Output Enable Input
Transmit/Receive Input
Side A Inputs or 3-STATE Outputs
Side B Inputs or 3-STATE Outputs
Description
Truth Table
Inputs
OE
L
L
H
T/R
L
H
X
Bus B Data to Bus A
Bus A Data to Bus B
HIGH-Z State
Outputs
H
=
HIGH Voltage Level L
=
LOW Voltage Level X
=
Immaterial
Any unused bus terminals during HIGH-Z State must be held HIGH or
LOW.
© 1999 Fairchild Semiconductor Corporation
DS011520.prf
www.fairchildsemi.com
74VHC245
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
CC
)
DC Input Voltage (V
IN
) (T/R, OE)
DC Output Voltage (V
OUT
)
Input Diode Current (I
IK
) (T/R, OE)
Output Diode Current (I
OK
)
DC Output Current (I
OUT
)
DC V
CC
/GND Current (I
CC
)
Storage Temperature (T
STG
)
Lead Temperature (T
L
)
(Soldering, 10 seconds)
260°C
−0.5V
to
+7.0V
−0.5V
to 7.0V
−0.5V
to V
CC
+
0.5V
−20
mA
±20
mA
±25
mA
±75
mA
−65°C
to
+150°C
Recommended Operating
Conditions
(Note 2)
Supply Voltage (V
CC
)
Input Voltage (V
IN
)(T/R, OE)
Output Voltage (V
OUT
)
Operating Temperature (T
OPR
)
Input Rise and Fall Time (t
r
, t
f
)
V
CC
=
3.3V
±
0.3V
V
CC
=
5.0V
±
0.5V
0
∼
100 ns/V
0
∼
20 ns/V
2.0V to 5.5V
0V to 5.5V
0V to V
CC
−40°C
to
+85°C
Note 1:
Absolute Maximum Ratings are values beyond which the device
may be damaged or have its useful life impaired. The databook specifica-
tions should be met, without exception, to ensure that the system design is
reliable over its power supply, temperature, and output/input loading vari-
ables. Fairchild does not recommend operation outside databook specifica-
tions.
Note 2:
Unused inputs or I/O pins must be held HIGH or LOW. They may
not float.
DC Electrical Characteristics
Symbol
V
IH
V
IL
V
OH
Parameter
HIGH Level
Input Voltage
LOW Level
Input Voltage
HIGH Level
Output Voltage
V
CC
(V)
2.0
3.0
−
5.5
2.0
3.0
−
5.5
2.0
3.0
4.5
3.0
4.5
V
OL
LOW Level
Output Voltage
2.0
3.0
4.5
3.0
4.5
I
OZ
3-STATE Output
Off-State Current
5.5
0
−
5.5
5.5
±0.25
±0.1
4.0
±2.5
±1.0
40.0
µA
µA
µA
1.9
2.9
4.4
2.58
3.94
0.0
0.0
0.0
0.1
0.1
0.1
0.36
0.36
2.0
3.0
4.5
T
A
=
25°C
Min
1.50
0.7 V
CC
0.50
0.3 V
CC
1.9
2.9
4.4
2.48
3.80
0.1
0.1
0.1
0.44
0.44
V
I
OL
=
4 mA
I
OL
=
8 mA
V
IN
=
V
CC
or GND
V
OUT
=
V
CC
or GND
V
IN
OE
=
V
IH
or V
IL
I
IN
(T/R, OE)
I
CC
Input Leakage
Current
Quiescent Supply Current
V
IN
=
V
CC
or GND
V
IN
=
5.5V or GND
V
V
I
OH
= −4
mA
I
OH
= −8
mA
V
IN
=
V
IH
I
OL
=
50
µA
or V
IL
V
Typ
Max
T
A
= −40°C
to
+85°C
Min
1.50
0.7 V
CC
0.50
0.3 V
CC
Max
V
V
V
IN
=
V
IH
I
OH
= −50 µA
or V
IL
Units
Conditions
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2
74VHC245
Noise Characteristics
Symbol
V
OLP
(Note 3)
V
OLV
(Note 3)
V
IHD
(Note 3)
V
ILD
(Note 3)
Parameter
Quiet Output Maximum
Dynamic V
OL
Quiet Output Minimum
Dynamic V
OL
Minimum HIGH Level
Dynamic Input Voltage
Maximum LOW Level
Dynamic Input Voltage
5.0
1.5
V
C
L
=
50 pF
5.0
3.5
V
C
L
=
50 pF
5.0
−0.9
−1.2
V
C
L
=
50 pF
V
CC
(V)
5.0
T
A
=
25°C
Typ
0.9
Limits
1.2
Units
V
C
L
=
50 pF
Conditions
Note 3:
Parameter guaranteed by design.
AC Electrical Characteristics
Symbol
t
PLH
t
PHL
Parameter
Propagation Delay
Time
5.0
±
0.5
t
PZL
t
PZH
3-STATE Output
Enable Time
5.0
±
0.5
t
PLZ
t
PHZ
t
OSLH
t
OSHL
C
IN
(T/R, OE)
C
I/O
C
PD
Output Capacitance
Power Dissipation
Capacitance
Note 4:
Parameter guaranteed by design. t
OSLH
=
|t
PLH max
−
t
PLH min
|; t
OSHL
=
|t
PHL max
−
t
PHL min
|
Note 5:
C
PD
is defined as the value of the internal equivalent capacitance which is calculated from the operating current consumption without load. Average
operating current can be obtained by the equation: I
CC
(opr.)
=
C
PD
* V
CC
* f
IN
+
I
CC
/8 (per Bit).
V
CC
(V)
3.3
±
0.3
T
A
=
25°C
Min
Typ
5.8
8.3
4.0
5.5
8.5
11.0
5.8
7.3
11.5
7.0
Max
8.4
11.9
5.5
7.5
13.2
16.7
8.5
10.6
15.8
9.7
1.5
1.0
4
10
T
A
= −40°C
to
+85°C
Min
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Max
10.0
13.5
6.5
8.5
15.5
19.0
10.0
12.0
18.0
11.0
1.5
1.0
10
Units
ns
ns
ns
ns
ns
ns
pF
Conditions
C
L
=
15 pF
C
L
=
50 pF
C
L
=
15 pF
C
L
=
50 pF
R
L
=
1 kΩ C
L
=
15 pF
C
L
=
50 pF
C
L
=
15 pF
C
L
=
50 pF
R
L
=
1 kΩ C
L
=
50 pF
C
L
=
50 pF
(Note 4)
C
L
=
50 pF
C
L
=
50 pF
V
CC
=
Open
V
CC
=
5.0V
(Note 5)
3.3
±
0.3
3-STATE Output
Disable Time
Output to Output
Skew
Input Capacitance
3.3
±
0.3
5.0
±
0.5
3.3
±
0.3
5.0
±
0.5
8
21
pF
pF
3
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74VHC245
Physical Dimensions
inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300” Wide
Package Number M20B
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
Package Number M20D
www.fairchildsemi.com
4
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