54LCX245
Low Voltage Bidirectional Transceiver with 5V Tolerant
Inputs and Outputs
General Description
The LCX245 contains eight non-inverting bidirectional buff-
ers with TRI-STATE™outputs and is intended for bus ori-
ented applications. The device is designed for low voltage
(3.3V) V
CC
applications with capability of interfacing to a 5V
signal environment. The T/R input determines the direction
of data flow through the device. The OE input disables both
theAand B ports by placing them in a high impedance state.
The LCX245 is fabricated with an advanced CMOS technol-
ogy to achieve high speed operation while maintaining
CMOS low power dissipation.
Features
n5V tolerant inputs and outputs
n9ns t
PD
max, 10µA I
CCQ
max
nPower down high impedance inputs and outputs
nSupports live insertion/withdrawal
n2.0V–3.6V V
CC
supply operation
n±24 mA output drive
nImplements patented noise/EMI reduction circuitry
nFunctionally compatible with the 54 series 245
nESD performance:
Human body model >2000V
Machine model >200V
nStandard Microcircuit Drawing (SMD) 5962-97543
Logic Symbols
Pin Descriptions
Pin Names Description
OE Output Enable Input
T/R Transmit/Receive Input
A
0
–A
7
Side A Inputs or 3-STATE Outputs
B
0
–B
7
Side B Inputs or 3-STATE Outputs
Connection Diagram
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
DS101022-1
Pin Assignment
for DIP and Cerpack
DS101022-3
Pin Assignment
for LCC
DS101022-6
December 1998
54LCX245 Low Voltage Bidirectional Transceiver with 5V Tolerant Inputs and Outputs
© 1998 National Semiconductor Corporation DS101022 www.national.com
Truth Table
Inputs Outputs
OE T/R
L L Bus B
0
–B
7
Data to Bus A
0
–A
7
L H Bus A
0
–A
7
Data to Bus B
0
–B
7
H X HIGH Z State on A
0
–A
7
,B
0
–B
7
(Note 1)
H=High Voltage Level
L=Low Voltage Level
X=Immaterial
Z=High Impedance
Note 1: Unused bus terminals during HIGH Z State must be held HIGH or LOW.
Logic Diagram
DS101022-4
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Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
) −0.5V to +7.0V
DC Input Voltage (V
I
) −0.5V to +7.0V
DC Input Diode Current (I
IK
)
V
I
<GND −50 mA
DC Output Diode Current (I
OK
)
V
O
<GND −50mA
V
O
≥V
CC
+50mA
DC Output Voltage (V
O
)
Output in High or Low State -0.5V to V
CC
+ 0.5V
Output in TRI-STATE -0.5V to 7.0V
DC Output Source or Sink Current
(I
O
)±50mA
DC V
CC
or Ground Current ±200mA
Storage Temperature Range
(T
STG
) −65˚C to +150˚C
Junction Temperature (T
J
)
CDIP 175˚C
Recommended Operating
Conditions (Note 3)
Supply Voltage (V
CC
)
Operating 2.0V to 3.6V
Data Retention 1.5V to 3.6V
Input Voltage (V
I
) 0V to 5.5V
Output Voltage (V
O
)
High or Low State 0V to V
CC
TRI-STATE 0V to 5.5V
Operating Temperature (T
A
)
54LCX −55˚C to +125˚C
Minimum Input Edge Rate (∆t/∆V)
V
IN
from 0.8V to 2.0V, V
CC
= 3.0V 0ns/V to 10ns/V
Note 2: The Absolute Maximum Ratings are those values beyond which the
safety of the device cannot be guaranteed. The device should not be oper-
ated at these limits. The parametric values defined in the Electrical Charac-
teristics tables are not guaranteed at the Absolute Maximum Ratings. The
“Recommended Operating Conditions” table will define the conditions for ac-
tual device operation.
Note 3: IOAbsolute Maximum Rating must be observed.
DC Electrical Characteristics
Symbol Parameter Conditions VCC TA=−55˚C to +125˚C Units
(V) Min Max
VIH HIGH Level Input Voltage 2.7–3.6 2.0 V
VIL LOW Level Input Voltage 2.7–3.6 0.8 V
VOH HIGH Level Output Voltage IOH =−100 µA 2.7–3.6 VCC − 0.2 V
IOH =−12 mA 2.7 2.2 V
IOH =−12 mA 3.0 2.4 V
IOH =−24 mA 3.0 2.2 V
VOL LOW Level Output Voltage IOL =100 µA 2.7–3.6 0.2 V
IOL =12 mA 2.7 0.4 V
IOL =24 mA 3.0 0.55 V
IIInput Leakage Current 0 ≤VI≤5.5V 2.7–3.6 ±5.0 µA
VIKL Clamp Diode Voltage IM= -18mA 3.0 -1.2 V
IOZ TRI-STATE I/O Leakage 0 ≤VO≤5.5V 2.7–3.6 ±5.0 µA
VI=VIH or VIL
ICCZ Supply Current Outputs
TRI-STATE VI=5.5V or GND 2.7-3.6 10 µA
IOFF Power-Off Leakage Current VCC = 0V, VI= 0V, VM=
5.5V 0 100 µA
ICC Quiescent Supply Current VI=VCC or GND 2.7-3.6 10 µA
∆ICC Increase in ICC per Input VIH =VCC −0.6V 2.7–3.6 0.5 mA
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AC Electrical Characteristics
Symbol Parameter TA=−55˚C to +125˚C, CL=50pF, RL=500ΩUnits
VCC =3.3V ±0.3V VCC =2.7V
Min Max Min Max
tPHL Propagation Delay 1.5 8.0 1.5 9.0 ns
tPLH Anto Bnor Bnto An1.5 8.0 1.5 9.0
tPZL Output Enable Time 1.5 10.0 1.5 11.0 ns
tPZH 1.5 10.0 1.5 11.0
tPLZ Output Disable Time 1.5 8.0 1.5 9.0 ns
tPHZ 1.5 8.0 1.5 9.0
tOSHL Output to Output Skew 1.0 1.0 ns
tOSLH (Notes 4, 5) 1.0 1.0
Note 4: Skew is defined as the absolute value of the difference between the actual propagation delay for any two separate outputs of the same device. The speci-
fication applies to any outputs switching in the same direction, either HIGH to LOW (tOSHL) or LOW to HIGH (tOSLH).
Note 5: Guaranteed but not tested (design characterization data).
Dynamic Switching Characteristics
Symbol Parameter Conditions VCC
(V) TA=25˚C Units
Max
VOLP Quiet Output Dynamic Peak VOL CL=50 pF, VIH =3.0V, VIL =0V 3.0 1.0 V
VOLV Quiet Output Dynamic Valley VOL CL=50 pF, VIH =3.0V, V IL =0V 3.0 -0.8 V
Capacitance
Symbol Parameter Conditions Max Units
CIN Input Capacitance VCC =Open, VI=0V or VCC 10 pF
CI/O Input/Output Capacitance VCC =3.3V, VI=0V or VCC 12 pF
CPD Power Dissipation Capacitance VCC =3.3V, VI=0V or VCC,f=10 MHz 30 pF
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Physical Dimensions inches (millimeters) unless otherwise noted
20-Lead Ceramic Dual-in-line
Package Number J20A
20-Lead Cerpack
Package Number W20A
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DE-
VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-
CONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or sys-
tems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose fail-
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component in any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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20-Lead Leadless Chip Carrier
Package Number E20A
54LCX245 Low Voltage Bidirectional Transceiver with 5V Tolerant Inputs and Outputs
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
