74VHCT245A
OCTAL BUS
TRANSCEIVER (3-STATE)
s
s
s
s
s
s
s
s
s
s
HIGH SPEED: t
PD
= 4.5 ns (TYP.) at V
CC
= 5V
LOW POWER DISSIPATION:
I
CC
= 4
µA
(MAX.) at T
A
=25°C
COMPATIBLE WITH TTL OUTPUTS:
V
IH
= 2V (MIN.), V
IL
= 0.8V (MAX)
POWER DOWN PROTECTION ON INPUTS
& OUTPUTS
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8 mA (MIN)
BALANCED PROPAGATION DELAYS:
t
PLH
≅
t
PHL
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 4.5V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 245
IMPROVED LATCH-UP IMMUNITY
LOW NOISE: V
OLP
= 0.9V (MAX.)
SOP
TSSOP
Table 1: Order Codes
PACKAGE
SOP
TSSOP
T&R
74VHCT245AMTR
74VHCT245ATTR
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.
Figure 1: Pin Connection And IEC Logic Symbols
December 2004
Rev. 4
1/13
74VHCT245A
Figure 2: Input/ Output Equivalent Circuit
Figure 3: Input Equivalent Circuit
Table 2: Pin Description
PIN N°
1
2, 3, 4, 5, 6,
7, 8, 9
18, 17, 16,
15, 14, 13,
12, 11
19
10
20
SYMBOL
DIR
A1 to A8
B1 to B8
NAME AND FUNCTION
Directional Control
Data Inputs/Outputs
Data Inputs/Outputs
G
GND
V
CC
Enable Input
Ground (0V)
Positive Supply Voltage
Table 3: Truth Table
INPUTS
G
L
L
H
X : Don‘t Care
Z : High Impedance
FUNCTION
OUTPUT
DIR
L
H
X
A BUS
OUTPUT
INPUT
Z
B BUS
INPUT
OUTPUT
Z
A=B
B=A
Z
2/13
74VHCT245A
Table 4: Absolute Maximum Ratings
Symbol
V
CC
V
I
V
I/O
V
I/O
I
IK
I
OK
I
O
Supply Voltage
DC Input Voltage (DIR, G)
DC BUS I/O Voltage (see note 1)
DC BUS I/O Voltage (see note 2)
DC Input Diode Current
DC Output Diode Current
DC Output Current
Parameter
Value
-0.5 to +7.0
-0.5 to +7.0
-0.5 to +7.0
-0.5 to V
CC
+ 0.5
- 20
±
20
±
25
±
75
-65 to +150
300
Unit
V
V
V
V
mA
mA
mA
mA
°C
°C
I
CC
or I
GND
DC V
CC
or Ground Current
Storage Temperature
T
stg
T
L
Lead Temperature (10 sec)
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. I
O
absolute maximum rating must be observed
Table 5: Recommended Operating Conditions
Symbol
V
CC
V
I
V
I/O
V
I/O
T
op
dt/dv
Supply Voltage
Input Voltage
BUS I/O Voltage (see note 1)
BUS I/O Voltage (see note 2)
Operating Temperature
Input Rise and Fall Time (see note 3) (V
CC
= 5.0
±
0.5V)
Parameter
Value
4.5 to 5.5
0 to 5.5
0 to 5.5
0 to V
CC
-55 to 125
0 to 20
Unit
V
V
V
V
°C
ns/V
1) Output in OFF State
2) High or Low State. I
O
absolute maximum rating must be observed
3) V
IN
from 0.8V to 2V
3/13
74VHCT245A
Table 6: DC Specifications
Test Condition
Symbol
Parameter
V
CC
(V)
4.5 to
5.5
4.5 to
5.5
4.5
4.5
4.5
4.5
5.5
0 to
5.5
5.5
5.5
0
I
O
=-50
µA
I
O
=-8 mA
I
O
=50
µA
I
O
=8 mA
V
I
= V
IH
or V
IL
V
O
= 0V to 5.5V
V
I
= 5.5V or GND
V
I
= V
CC
or GND
One Input at 3.4V,
other input at V
CC
or GND
V
OUT
= 5.5V
T
A
= 25°C
Min.
2
0.8
4.4
3.94
0.0
0.1
0.36
±0.25
±
0.1
4
1.35
0.5
4.5
4.4
3.8
0.1
0.44
±
2.5
±
1.0
40
1.5
5.0
Typ.
Max.
Value
-40 to 85°C
Min.
2
0.8
4.4
3.7
0.1
0.55
±
2.5
±
1.0
40
1.5
5.0
Max.
-55 to 125°C
Min.
2
0.8
Max.
V
V
V
V
µA
µA
µA
mA
µA
Unit
V
IH
V
IL
V
OH
V
OL
I
OZ
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
Low Level Output
Voltage
High Impedance
Output Leakage
Current
Input Leakage
Current
Quiescent Supply
Current
Additional Worst
Case Supply
Current
Output Leakage
Current
I
I
I
CC
+I
CC
I
OPD
Table 7: AC Electrical Characteristics
(Input t
r
= t
f
= 3ns)
Test Condition
Symbol
Parameter
V
CC
(*)
C
L
(V)
(pF)
5.0
5.0
5.0
5.0
5.0
5.0
15
50
15
50
50
50
RL = 1K
Ω
RL = 1K
Ω
T
A
= 25°C
Min.
Typ.
4.5
5.3
9.0
9.7
10.0
Max.
7.5
8.7
13.8
14.8
15.4
1.0
Value
-40 to 85°C
Min.
1.0
1.0
1.0
1.0
1.0
Max.
8.5
9.5
15.0
16.0
16.5
1.0
-55 to 125°C
Min.
1.0
1.0
1.0
1.0
1.0
Max.
10.0
11.0
16.0
17.0
17.5
1.0
ns
ns
ns
ns
Unit
t
PLH
t
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
t
OSLH
t
OSHL
Propagation Delay
Time
Output Enable
Time
Output Disable
Time
Output to Output
Skew Time (note 1)
(*) 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
|
4/13
74VHCT245A
Table 8: Capacitive Characteristics
Test Condition
Symbol
Parameter
T
A
= 25°C
Min.
C
IN
C
I/O
C
PD
Input Capacitance
Bus Input
Capacitance
Power Dissipation
Capacitance
(note 1)
Typ.
6
8
18
Max.
10
Value
-40 to 85°C
Min.
Max.
10
-55 to 125°C
Min.
Max.
10
pF
pF
pF
Unit
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)
Table 4: DYNAMIC SWITCHING CHARACTERISTICS
Test Condition
Symbol
Parameter
V
CC
(V)
5.0
T
A
= 25°C
Min.
Typ.
0.6
-0.9
C
L
= 50 pF
2.0
-0.6
V
Max.
0.9
Value
-40 to 85°C
Min.
Max.
-55 to 125°C
Min.
Max.
Unit
V
OLP
V
OLV
V
IHD
V
ILD
Dynamic Low
Voltage Quiet
Output (note 1, 2)
Dynamic High
Voltage Input
(note 1, 3)
Dynamic Low
Voltage Input
(note 1, 3)
5.0
5.0
0.8
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.
5/13
