Page 1
74VHC245
OCTAL BUS
TRANSCEIVER (3-STATE)
■ HIGH SPEED: t
■ LOW POWER DISSIPATION:
I
= 4 µA (MAX.) at TA=25°C
CC
■ HIGH NOISE IMMUNITY:
V
= V
NIH
■ POWER DOWN PROTECTION ON
NIL
= 4.0 ns (TYP.) at VCC = 5V
PD
= 28% VCC (MIN.)
CONTROL INPUTS
■ SYMMETRICAL OUTPUT IMPEDANCE:
|I
| = IOL = 8 mA (MIN)
OH
■ BALANCED PROPAGATION DELAYS:
t
≅ t
PLH
■ OPERATING VOLTAGE RANGE:
V
CC
■ PIN AND FUNCTION COMPATIBLE WITH
PHL
(OPR) = 2V to 5.5V
74 SERIES 245
■ IMPROVED LATCH-UP IMMUNITY
■ LOW NOISE: V
= 0.9V (MAX.)
OLP
DESCRIPTION
The 74VHC245 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
TSSOPSOP
Table 1: Order Codes
PACKAGE T & R
SOP 74VHC245MTR
TSSOP 74VHC245TTR
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
effectivel y isolated.
All inputs and outputs are equipped with
protection circuits against static disc harge, 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
Rev. 6
1/12November 2004
Page 2
74VHC245
Figure 2: Input Equivalent Circuit Table 2: Pin Description
PIN N° SYMBOL NAME AND FUNCTION
1 DIR Directional Control
2, 3, 4, 5, 6,
7, 8, 9
18, 17, 16,
15, 14, 13,
12, 11
19 G
10 GND Ground (0V)
20 V
Table 3: Truth Table
A1 to A8 Data Inputs/Outputs
B1 to B8 Data Inputs/Outputs
Output Enable Input
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
HXZZZ
X : Don‘t Care
Z : High Impedance
Table 4: Absolute Maximum Ratings
Symbol Parameter Value Unit
V
V
V
V
I
I
OK
I
or I
I
CC
T
T
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
Supply Voltage
CC
DC Input Voltage (DIR, G)
I
Bus I/O Voltage -0.5 to VCC + 0.5
I/O
DC Output Voltage -0.5 to VCC + 0.5
O
DC Input Diode Current
IK
DC Output Diode Current
DC Output Current
O
DC VCC or Ground Current
GND
Storage Temperature
stg
Lead Temperature (10 sec)
L
-0.5 to +7.0 V
-0.5 to +7.0 V
V
V
- 20 mA
± 20 mA
± 25 mA
± 75 mA
-65 to +150 °C
300 °C
Table 5: Recommended Operating Conditions
Symbol Parameter Value Unit
V
V
V
V
T
dt/dv
1) VIN from 30 % t o 70% of V
Supply Voltage
CC
Input Voltage (DIR, G)
I
Bus I/O Voltage 0 to V
I/O
Output Voltage 0 to V
O
Operating Temperature
op
Input Rise and Fall Time (note 1) (V
(V
CC
= 3.3 ± 0.3V)
CC
= 5.0 ± 0.5V)
CC
2 to 5.5 V
0 to 5.5 V
CC
CC
-55 to 125 °C
0 to 100
0 to 20
2/12
V
V
ns/V
Page 3
Table 6: DC Specifications
Symbol Parameter
V
V
V
High Level Input
IH
Voltage
V
Low Level Input
IL
Voltage
High Level Output
OH
Voltage
Low Level Output
OL
Voltage
I
High Impedance
OZ
Output Leakage
Current
Input Leakage
I
I
Current
I
Quiescent Supply
CC
Current
74VHC245
Test Condition Value
= 25°C
T
V
(V)
CC
A
Min. Typ. Max. Min. Max. Min. Max.
2.0 1.5 1.5 1.5
3.0 to
5.5
0.7V
CC
2.0 0.5 0.5 0.5
3.0 to
5.5
2.0
3.0
4.5
3.0
4.5
2.0
3.0
4.5
3.0
4.5
5.5
0 to
5.5
5.5
IO=-50 µA
I
=-50 µA
O
=-50 µA
I
O
=-4 mA
I
O
=-8 mA
I
O
IO=50 µA
=50 µA
I
O
=50 µA
I
O
=4 mA
I
O
=8 mA
I
O
= VIH or V
V
I
IL
VO = VCC or GND
V
= 5.5V or GND
I
= VCC or GND
V
I
1.9 2.0 1.9 1.9
2.9 3.0 2.9 2.9
4.4 4.5 4.4 4.4
2.58 2.48 2.4
3.94 3.8 3.7
0.3V
0.0 0.1 0.1 0.1
0.0 0.1 0.1 0.1
0.0 0.1 0.1 0.1
±0.25 ± 2.5 ± 2.5 µA
-40 to 85°C -55 to 125°C
CC
0.7V
CC
0.3V
CC
0.7V
CC
0.36 0.44 0.55
0.36 0.44 0.55
± 0.1 ± 1 ± 1 µA
44040µA
0.3V
CC
Unit
V
V
V
V
3/12
Page 4
74VHC245
Table 7: AC Electrical Characteristics (Input tr = tf = 3ns)
Test Condition Value
Symbol Parameter
t
Propagation Delay
PLH
t
t
t
t
t
t
OSLH
t
OSHL
Time
PHL
Output Disable
PZL
Time
PZH
PLZ
Output Enable
PHZ
Time
Output to Output
Skew time (note 1)
V
3.3
3.3
5.0
5.0
3.3
3.3
5.0
5.0
3.3
5.0
3.3
5.0
C
CC
(V)
L
(pF)
(*)
15 5.8 8.4 1.0 10.0 1.0 10.0
(*)
50 8.3 11.9 1.0 13.5 1.0 13.5
(**)
15 4.0 5.5 1.0 6.5 1.0 6.5
(**)
50 5.5 7.5 1.0 8.5 1.0 8.5
(*)
15
(*)
50
(**)
15
(**)
50
(*)
50
(**)
50
(*)
50 1.5 1.5 1.5
(**)
50 1.0 1.0 1.0
R
L
R
L
R
L
R
L
R
L
R
L
= 1KΩ
= 1KΩ
= 1KΩ
= 1KΩ
= 1KΩ
= 1KΩ
T
Min. Typ. Max. Min. Max. Min. Max.
= 25°C
A
-40 to 85°C -55 to 125°C
8.5 13.2 1.0 15.5 1.0 15.5
11.0 16.7 1.0 19.0 1.0 19.0
5.8 8.5 1.0 10.0 1.0 10.0
7.3 10.6 1.0 12.0 1.0 12.0
11.5 15.8 1.0 18.0 1.0 18.0
7.0 9.7 1.0 11.0 1.0 11.0
Unit
ns
ns
ns
ns
(*) Voltage range is 3.3V ± 0.3V
(**) Voltage range is 5.0V ±
Note 1: Parameter guaranteed by design. t
0.5V
soLH
= |t
pLHm
- t
pLHn
|, t
soHL
= |t
pHLm
- t
pHLn
|
Table 8: Capacitive Characteristics
Test Condition Value
= 25°C
Symbol Parameter
T
A
Min. Typ. Max. Min. Max. Min. Max.
C
C
C
Input Capacitance
IN
Output
I/O
Capacitance
Power Dissipation
PD
Capacitance
410 10 10pF
8pF
21 pF
(note 1)
1) CPD 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
-40 to 85°C -55 to 125°C
= CPD x VCC x fIN + ICC/8 (per c ircuit )
CC(opr)
Unit
4/12
Page 5
Table 9: Dynamic Switching Characteristics
Test Condition Value
Symbol Parameter
V
V
Dynamic Low
OLP
Voltage Quiet
OLV
Output (note 1, 2)
V
(V)
5.0
CC
T
A
Min. Typ. Max. Min. Max. Min. Max.
0.6 0.9
-0.9 -0.6
-40 to 85°C -55 to 125°C
= 25°C
Dynamic High
V
IHD
Voltage Input
5.0 3.5 V
= 50 pF
C
L
(note 1, 3)
Dynamic Low
V
ILD
Voltage Input
5.0 1.5 V
(note 1, 3)
1) Worst case package.
2) Max number of outp ut s defined as (n). Data inpu t s are driven 0V to 5.0V, (n-1) outputs switc hi ng and one output at GND.
3) Max number of data inputs (n) switching. (n-1) switching 0V to 5.0V. Inputs under test switching: 5.0V to threshold (V
(V
), f=1MHz.
IHD
ILD
Figure 3: Test Circuit
74VHC245
Unit
V
), 0V to thresho l d
TEST SWITCH
t
, t
PLH
PHL
, t
t
PZL
PLZ
t
, t
PZH
PHZ
CL =15/ 50pF or e qui valent (includes jig an d probe capacit ance)
= R1 = 1KΩ or equivalent
R
L
R
= Z
of pulse generator (typically 50Ω)
T
OUT
Open
V
CC
GND
5/12
Page 6
74VHC245
Figure 4: Waveform - Propagation Delays (f=1MHz; 50% duty cycle)
Figure 5: Waveform - Output Enable And Disable Time (f=1MHz; 50% duty cycle)
6/12
Page 7
SO-20 MECHANICAL DATA
74VHC245
DIM.
A 2.35 2.65 0.093 0.104
A1 0.1 0.30 0.004 0.012
B 0.33 0.51 0.013 0.020
C 0.23 0.32 0.009 0.013
D 12.60 13.00 0.496 0.512
E 7.4 7.6 0.291 0.299
e 1.27 0.050
H 10.00 10.65 0.394 0.419
h 0.25 0.75 0.010 0.030
L 0.4 1.27 0.016 0.050
k0° 8° 0° 8°
ddd 0.100 0.004
MIN. TYP MAX. MIN. TYP. MAX.
mm. inch
0016022D
7/12
Page 8
74VHC245
TSSOP20 MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 1.2 0.047
A1 0.05 0.15 0.002 0.004 0.006
A2 0.8 1 1.05 0.031 0.039 0.041
b 0.19 0.30 0.007 0.012
c 0.09 0.20 0.004 0.0079
D 6.4 6.5 6.6 0.252 0.256 0.260
E 6.2 6.4 6.6 0.244 0.252 0.260
E1 4.3 4.4 4.48 0.169 0.173 0.176
e 0.65 BSC 0.0256 BSC
K0˚ 8˚0˚ 8˚
L 0.45 0.60 0.75 0.018 0.024 0.030
A2
A
A1
b
e
K
c
L
E
D
E1
PIN 1 IDENTIFICATION
8/12
1
0087225C
Page 9
74VHC245
Tape & Reel SO-20 MECHANICAL
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 30.4 1.197
Ao 10.8 11 0.425 0.433
Bo 13.2 13.4 0.520 0.528
Ko 3.1 3.3 0.122 0.130
Po 3.9 4.1 0.153 0.161
P 11.9 12.1 0.468 0.476
DATA
9/12
Page 10
74VHC245
Tape & Reel TSSOP20 MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.8 7 0.268 0.276
Bo 6.9 7.1 0.272 0.280
Ko 1.7 1.9 0.067 0.075
Po 3.9 4.1 0.153 0.161
P 11.9 12.1 0.468 0.476
10/12
Page 11
Table 10: Revision History
Date Revisio n Description of Changes
12-Nov-2004 6 Order Codes Revision - pag. 1.
74VHC245
11/12
Page 12
74VHC245
Information fur nished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
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