1/10
June 2001
s
HIGH SPEED: t
PD
= 4.5 ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A (MAX.) at T
A
=25C
s
COMPATIBLE WITH TTL OUTPUTS:
V
IH
= 2V (MIN.), V
IL
= 0.8V (MAX)
s
POWER DOWN PROTECTION ON INPUTS
& OUTPUTS
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8 mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 4.5V to 5.5V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 245
s
IMPROVED LATCH-UP IMMUNITY
s
LOW NOISE: V
OLP
= 0.9V (MAX.)
DESCRIPTION
The 74VHCT245A is an advanced high-speed
CMOS OCTAL BUS TRANSCEIVER (3-STATE)
fabricated with sub-micron silicon gate and
double-layer metal wiring C
2
MOS technology.
This IC is intended for two-way asynchronous
communication between data busses; the
direction of data transmission is determined by
DIR input. The enable input G can be used to
disable the device so that the busses are
effectively isolated.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
All floating bus terminals during High Z State must
be held HIGH or LOW.
74VHCT245A
OCTAL BUS
TRANSCEIVER (3-STATE)
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
SOP
74VHCT245AM
74VHCT245AMTR
TSSOP
74VHCT245ATTR
TSSOP
SOP
74VHCT245A
2/10
INPUT/ OUTPUT EQUIVALENT CIRCUIT
INPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
TRUTH TABLE
X : Don`t Care
Z : High Impedance
PIN No
SYMBOL
NAME AND FUNCTION
1
DIR
Directional Control
2, 3, 4, 5, 6,
7, 8, 9
A1 to A8
Data Inputs/Outputs
18, 17, 16,
15, 14, 13,
12, 11
B1 to B8
Data Inputs/Outputs
19
G
Enable Input
10
GND
Ground (0V)
20
V
CC
Positive Supply Voltage
INPUTS
FUNCTION
OUTPUT
G
DIR
A BUS
B BUS
L
L
OUTPUT
INPUT
A = B
L
H
INPUT
OUTPUT
B = A
H
X
Z
Z
Z
74VHCT245A
3/10
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
1) Output in OFF State
2) High or Low State. Io absolute maximum rating must be observed
RECOMMENDED OPERATING CONDITIONS
1) Output in OFF State
2) High or Low State. Io absolute maximum rating must be observed
3) VIN from 0.8V to 2V
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7.0
V
V
I
DC Input Voltage (DIR, G)
-0.5 to +7.0
V
V
I/O
DC BUS I/O Voltage (see note 1)
-0.5 to +7.0
V
V
I/O
DC BUS I/O Voltage (see note 2)
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
- 20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
25
mA
I
CC
or I
GND
DC V
CC
or Ground Current
75
mA
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to 5.5
V
V
I/O
BUS I/O Voltage (see note 1)
0 to 5.5
V
V
I/O
BUS I/O Voltage (see note 2)
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
dt/dv
Input Rise and Fall Time (see note 3) (V
CC
= 5.0
0.5V)
0 to 20
ns/V
74VHCT245A
4/10
DC SPECIFICATIONS
AC ELECTRICAL CHARACTERISTICS (Input t
r
= t
f
= 3ns)
(*) Voltage range is 5.0V
0.5V
Note 1 : Parameter guaranteed by design. t
soLH
= |t
pLHm
- t
pLHn
|, t
soHL
= |t
pHLm
- t
pHLn
|
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
4.5 to
5.5
2
2
2
V
V
IL
Low Level Input
Voltage
4.5 to
5.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-50
A
4.4
4.5
4.4
4.4
V
4.5
I
O
=-8 mA
3.94
3.8
3.7
V
OL
Low Level Output
Voltage
4.5
I
O
=50
A
0.0
0.1
0.1
0.1
V
4.5
I
O
=8 mA
0.36
0.44
0.55
Ioz
High Impedance
Output Leakage
Current
5.5
V
I
= V
IH
or V
IL
V
O
= 0V to 5.5V
0.25
2.5
2.5
A
I
I
Input Leakage
Current
0 to
5.5
V
I
= 5.5V or GND
0.1
1.0
1.0
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
40
A
I
CC
Additional Worst
Case Supply
Current
5.5
One Input at 3.4V,
other input at V
CC
or GND
1.35
1.5
1.5
mA
I
OPD
Output Leakage
Current
0
V
OUT
= 5.5V
0.5
5.0
5.0
A
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(*)
(V)
C
L
(pF)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
PLH
t
PHL
Propagation Delay
Time
5.0
15
4.5
7.5
1.0
8.5
1.0
10.0
ns
5.0
50
5.3
8.7
1.0
9.5
1.0
11.0
t
PZL
t
PZH
Output Enable
Time
5.0
15
RL = 1K
9.0
13.8
1.0
15.0
1.0
16.0
ns
5.0
50
9.7
14.8
1.0
16.0
1.0
17.0
t
PLZ
t
PHZ
Output Disable
Time
5.0
50
RL = 1K
10.0
15.4
1.0
16.5
1.0
17.5
ns
t
OSLH
t
OSHL
Output to Output
Skew Time (note 1)
5.0
50
1.0
1.0
1.0
ns
74VHCT245A
5/10
CAPACITIVE CHARACTERISTICS
1) C
PD
is defined as the value of the IC's internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/8 (per circuit)
DYNAMIC SWITCHING CHARACTERISTICS
1) Worst case package.
2) Max number of outputs defined as (n). Data inputs are driven 0V to 3.0V, (n-1) outputs switching and one output at GND.
3) Max number of data inputs (n) switching. (n-1) switching 0V to 3.0V. Inputs under test switching: 3.0V to threshold (V
ILD
), 0V to threshold
(V
IHD
), f=1MHz.
Symbol
Parameter
Test Condition
Value
Unit
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
6
10
10
10
pF
C
I/O
Bus Input
Capacitance
8
pF
C
PD
Power Dissipation
Capacitance
(note 1)
18
pF
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
OLP
Dynamic Low
Voltage Quiet
Output (note 1, 2)
5.0
C
L
= 50 pF
0.6
0.9
V
V
OLV
-0.9
-0.6
V
IHD
Dynamic High
Voltage Input
(note 1, 3)
5.0
2.0
V
ILD
Dynamic Low
Voltage Input
(note 1, 3)
5.0
0.8
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