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Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s
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© 2003 Fairchild Semiconductor Corporation DS01 1540 www.fairchildsemi.com
January 1993
Revised September 2003
74LVX4245 8-Bit Dual Supply Translating Transceiver with 3-STATE Outputs
74LVX4245
8-Bit Dual Supply Translating Transceiver
with 3-STATE Outputs
General Description
The LVX 4245 is a du al-supp ly, 8 -bit tran slating transcei ver
that is designed to interface between a 5V bus and a 3V
bus in a mixed 3V/5V supply environment. The Transmit/
Receive (T/R) input determines the direction of data flow.
Transmit (active-HIGH) enables data from A Ports to B
Ports; R eceive (ac tive-LOW ) enable s data fro m B Ports to
A Ports. The Output Enable input, when HIGH, disables
both A and B Ports by placing them in a high impedance
condition. The A Port interfaces with the 5V bus; the B Port
interfaces with the 3V bus.
The LVX4245 is suitable for mixed voltage applications
such as laptop computers using 3.3V CPU’s and 5V LCD
displays.
Features
Bidirectional interface between 5V and 3V buses
Control inputs compatible with TTL level
5V data flow at A Port and 3V data flow at B Port
Outputs source/sink 24 mA at 5V bus; 12 mA at 3V bus
Guaranteed simultaneous switching noise level and
dynamic thresh ol d per for man ce
Implements patented EMI reduction circuitry
Functionally compatible with the 74 series 245
Ordering Code:
Devices also available in Tape and R eel. Specify by appending the suffix lett er X to the ordering code.
Logic Symbol
Connection Diagram
Pin Descriptions
Truth Table
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immateria l
Order Number Package Number Package Description
74LVX4245WM M24B 24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
74LVX4245QSC MQA24 24-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150" Wide
74LVX4245MTC MTC24 24-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Pin Nam es Descri ption
OE Output Enable Input
T/R Transmit/Receive Input
A0A7Side A Inputs or 3-STATE Outputs
B0B7Side B Inputs or 3-STATE Outputs
Inputs Outputs
OE T/R
L L Bus B Data to Bus A
L H Bus A Data to Bus B
H X HIGH-Z State
www.fairchildsemi.com 2
74LVX4245
Logic Diagram
3 www.fairchildsemi.com
74LVX4245
Absolute Maxim um Ratings(Note 1) Recommended Operating
Conditions (Note 2)
Note 1: The Absolute Maximum Ratings are those value s beyond whic h
the saf ety of the device cannot b e guaranteed . The device should not be
operated at these limits. The parametric values defined in the Electrical
Char ac teristics tables are not guaranteed at t he absolute maxim um ratings .
The R ecomm ended Ope rating Co ndition s table will define the condit ions
for actu al device operation.
Note 2: Unused inputs must he held HIGH or LOW. They may not floa t.
DC Electrical Characteristics
Supply Voltage (VCCA, VCCB)0.5V to +7.0V
DC Input Voltage (VI) @ OE, T/R 0.5V to VCCA + 0.5V
DC Input/Output Voltage (VI/O)
@ An0.5V to VCCA + 0.5V
@Bn0.5V to VCCB + 0.5V
DC Input Diode Current (IIN)
@ OE, T/R ±20 mA
DC Output Diode Current (IOK)±50 mA
DC O utput Source or Sink Current
(IO)±50 mA
DC VCC or Ground Current
per Output Pin (ICC or IGND)±50 mA
and Max Current @ ICCA ±200 mA
@ ICCB ±100 mA
Storage Temperature Range
(TSTG)65°C to +150°C
DC Latch-Up Source or
Sink Current ±300 mA
Supply Voltage
VCCA 4.5V to 5.5V
VCCB 2.7V to 3.6V
Input Voltage (VI) @ OE, T/R 0V to VCCA
Input/Output Voltage (VI/O)
@ An0V to VCCA
@ Bn0V to VCCB
Free Air Operating Temperature (TA)40°C to +85°C
Minimum Input Edge Rate (t/V) 8 ns/V
VIN from 30% to 70% of VCC
VCC @ 3.0V, 4.5V, 5.5V
Symbol Parameter VCCA VCCB TA +25°CT
A = 40°C to +85°CUnits Conditions
(V) (V) Typ Guaranteed Limits
VIHA Minimum An, T/R, 5.5 3.3 2.0 2.0
V
VOUT 0.1V or
HIGH Level OE 4.5 3.3 2.0 2.0 VCC 0.1V
VIHB Input Voltage Bn5.0 3.6 2.0 2.0
5.0 2.7 2.0 2.0
VILA Maximum An, T/R, 5.5 3.3 0.8 0.8
V
VOUT 0.1V or
LOW Level OE 4.5 3.3 0.8 0.8 VCC 0.1V
VILB Input Voltage Bn5.0 2.7 0.8 0.8
5.0 3.6 0.8 0.8
VOHA Minimum HIGH Level 4.5 3.0 4.5 4.4 4.4 VIOUT = 100 µA
Output Voltage 4.5 3.0 4.25 3.86 3.76 IOH = 24 mA
VOHB 4.5 3.0 2.99 2.9 2.9 VIOUT = 100 µA
4.5 3.0 2.8 2.4 2.4 IOH = 12 mA
4.5 2.7 2.5 2.4 2.4 IOL = 8 mA
VOLA Maximum LOW Level 4.5 3.0 0.002 0.1 0.1 V IOUT =100 µA
Output Voltage 4.5 3.0 0.18 0.36 0.44 IOL = 24 mA
VOLB 4.5 3.0 0.002 0.1 0.1 IOUT = 100 µA
4.5 3.0 0.1 0.31 0.4 V IOL = 12 mA
4.5 2.7 0.1 0.31 0.4 IOL = 8 mA
IIN Maximum Input VI = VCCA, GND
Leakage Current 5.5 3.6 ±0.1 ±1.0 µA
@ OE, T/R
IOZA Maximum 3-STATE VI = VIL, VIH
Output Leakage 5.5 3.6 ±0.5 ±5.0 µAOE = VCCA
@ AnVO = VCCA, GND
IOZB Maximum 3-STATE VI = VIL, VIH
Output Leakage 5.5 3.6 ±0.5 ±5.0 µAOE = VCCA
@ BnVO = VCCB, GND
ICC Maximum ICCT/Input 5.5 3.6 1.0 1.35 1.5 mA VI = VCCA 2.1V
@ An, T/R, OE
Input @ Bn5.5 3.6 0.35 0.5 mA VI = VCCB 0.6V
www.fairchildsemi.com 4
74LVX4245
DC Electrical Characteristics (Continued)
Note 3: Maximum test dura tio n 2. 0 ms, one ou t put loaded at a tim e.
Note 4: Worst case package.
Note 5: Max num ber of output s d ef ined as (n). D at a inputs are driven 0V to VCC level; one output at GN D .
Note 6: Max num ber of Data Inputs (n) swit c hing. (n1) inputs switch ing 0V to VCC level. I nput-unde r-t es t s w it c hing:
VCC level to threshold (VIHD), OV to thresh old (VILD) , f = 1 MHz.
AC Electrical Characteristics
Note 7: Voltage Range 5.0V is 5.0V ± 0.5V.
Note 8: Voltage Range 3.3V is 3.3V ± 0.3V.
Note 9: 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
specif ic ation applie s to an y out puts switching in the same direc t ion, either HIGH-to-LOW (tOSHL) or LOW-to-HIGH (t OSLH). Parameter guaranteed by design.
Symbol Parameter VCCA VCCB TA +25°CT
A = 40°C to +85°CUnits Conditions
(V) (V) Typ Guaranteed Limits
ICCA Quiescent VCCA An = VCCA or GND
Supply Current 5.5 3.6 8 80 µAB
n = VCCB or GND,
OE = GND T/R = GND
ICCB Quiescent VCCB An = VCCA or GND
Supply Current 5.5 3.6 5 50 µAB
n = VCCB or GND,
OE = GND T/R = VCCA
VOLPA Quiet Output Maximum 5.0 3.3 1.5 V(Note 4)(Note 5)
VOLPB Dynamic VOL 5.0 3.3 0.8
VOLVA Quiet Output Minimum 5.0 3.3 1.2 V(Note 4)(Note 5)
VOLVB Dynamic VOL 5.0 3.3 0.8
VIHDA Minimum HIGH Level 5.0 3.3 2.0 V(Note 4)(Note 6)
VIHDB Dynamic Input Voltage 5.0 3.3 2.0
VILDA Maximum LOW Level 5.0 3.3 0.8 V(Note 4)(Note 6)
VILDB Dynamic Input Voltage 5.0 3.3 0.8
Symbol Parameters
TA = +25°CT
A = 40°C to +85°CT
A = 40°C to +85°C
Units
CL = 50 pF CL = 50 pF CL = 50 pF
VCCA = 5V (Not e 7) VCCA = 5V (Note 7) VCCA = 5V (Note 7)
VCCB = 3.3V (Note 8) VCCB = 3.3V (Note 8) VCCB = 2.7V
Min Typ Max Min Max Min Max
tPHL Propagation Delay 1.0 5.1 8.5 1.0 9.0 1.0 10. 0 ns
tPLH A to B 1.0 5.3 8.5 1.0 9.0 1.0 10.0
tPHL Propagation Delay 1.0 5.4 8.5 1.0 9.0 1.0 10. 0 ns
tPLH B to A 1.0 5.5 8.5 1.0 9.0 1.0 10.0
tPZL Output Enable Time 1.0 6.5 10.0 1.0 10.5 1.0 11.5 ns
tPZH OE to B 1.0 6.7 10.0 1.0 10.5 1.0 11.5
tPZL Output Enable Time 1.0 5.2 9.0 1.0 9.5 1.0 10.0 ns
tPZH OE to A 1.0 5.8 9.0 1.0 9.5 1.0 10.0
tPHZ Output Disable Time 1.0 6.0 9.5 1.0 10.0 1.0 10.0 ns
tPLZ OE to B 1.0 3.3 6.5 1.0 7.0 1.0 7.5
tPHZ Output Disable Time 1.0 3.9 7.0 1.0 7.5 1.0 7.5 ns
tPLZ OE to A 1.0 2.9 6.5 1.0 7.0 1.0 7.5
tOSHL Output to Output
tOSLH Skew (Note 9) 1.0 1.5 1.5 1.5 ns
Data to Output
5 www.fairchildsemi.com
74LVX4245
Capacitance
Note 10: CPD is measu red at 10 MHz
8-Bit Dual Supply Translating Transceiver
The LVX4245 is a dual supply device capable of bidirec-
tional signal translation. This level shifting ability provides
an efficient interface between low voltage CPU local bus
with memo ry and a standar d bus defined by 5V I/O levels.
The device control inputs can be controlled by either the
low vol tage CPU an d core logi c or a bus arbitra tor w ith 5V
I/O levels.
Manufactured on a sub-micron CMOS process, the
LVX4245 is ideal for mixed voltage applications such as
notebook computers using 3.3V CPUs and 5V peripheral
devices.
Power Up Considerations
To insure the system does not experience unnecessary ICC
current draw, bus contention, or oscillations during power
up, the f ollowing guidel ines should be a dhered to (re fer to
Table 1):
Power up the control side of t he device first. This is the
VCCA.
OE should ramp with or ahead of VCCA. This will help
guar d against bus contention.
The Transmit/Receive control pin (T/R) should ramp with
or ahead of VCCA, this will ensure that the A Port data
pins are configured as inputs. With VCCA receiving
power first, the A I/O Port should be configured as inputs
to help guard against bus contention and oscillations.
A side data inp uts sh ould be dr iven to a val id logic l eve l.
This will prevent excessive current draw.
The above steps will ensure that no bus contention or oscil-
lations, and therefore no excessive current draw occurs
during the power up cycli ng of these devices. These steps
will help prevent possible damage t o the t ranslator device s
and potential damage to other system components.
TABLE 1. Low Voltage T ranslator Power Up Sequencing Table
Please reference Application Note AN-5001 for more detailed information on using Fairchilds LVX Low Voltage Dual
Supply CMOS Translating Transceivers.
Symbol Parameter Typ Units Conditions
CIN Input Capacitance 4.5 pF VCC = Open
CI/O Input/Output 15 pF VCCA = 5.0V
Capacitance VCCB = 3.3V
CPD Power Dissipation BA55 pF V
CCA = 5.0V
Capacitance (Note 10) AB40 pF V
CCB = 3.3V
Device Type VCCA VCCB T/R OE A Side
I/O B Side
I/O Floatable Pin
Allowed
74LVX4245 5V 3V ramp ramp logic outputs No
(power up 1st) (power up 2nd) with VCCA with VCCA 0V or VCCA
www.fairchildsemi.com 6
74LVX4245
Applications: Mixed Mode Dual Supply Interface Solution
LVX4245 is designed to solve 3V/5V interfacing issues
when C MO S de vi ces c ann ot toler ate I/O l eve ls ab ove the ir
applied VCC. If an I/O pin of 3V ICs is driven by 5V ICs, the
P-Channel transistor in 3V ICs will conduct causing current
flow from I/O bus to the 3V power supply. The resulting
high current flow ca n cause destr uction of 3V ICs through
latchup effects. To prevent this problem, a current limiting
resist or is used typi cally under d irect connect ion of 3V ICs
and 5V ICs, but it causes speed degradation.
In a better solution, the LVX4245 configures two different
output levels to handle the dual supply interface issues.
The A port is a dedicated 5V port to interface 5V ICs. The
B port is a dedicated port to interface 3V ICs. Figure 2
shows how LVX 4245 fits int o a system with 3V subsystem
and 5V subsystem.
This de vice is also co nfigured as a n 8-bit 245 t ransceiver,
giving the designer 3-STATE capabilities and the ability to
select either bidirectional or unidirectional modes. Since
the center 20 pins are also pin compatible to 74 series 245,
as shown in Figure 1, the de signe r co uld use this devic e i n
either a 3V system or a 5V system without any further work
to re-layout the board.
FIGURE 1. LVX4245 Pin Arrangement is Compatible to
20-Pin 74 Series 245
FIGURE 2. LVX4245 Fits into a System with 3V Subsystem and 5V Subsystem
7 www.fairchildsemi.com
74LVX4245
Physical Dim ensions inches (millimeters) unless otherwise noted
24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
Package Number M24B
24-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150" Wide
Package Number MQA24
www.fairchildsemi.com 8
74LVX4245 8-Bit Dual Supply Translating Transceiver with 3- STATE Outputs
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
24-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Package Number MTC24
Fairchild does not assu me any responsibility for use of any circuitry de scribed, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
LIFE SUPPORT POLICY
FAIRCHILDS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
1. Life suppor t de vices o r syste ms are devices or syste ms
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instructions for use provided in the labeling, can be rea-
sonably expected to result in a significant injury to the
user.
2. A critical compon ent i n any compon ent of a lif e supp ort
device or system whose failure to perform can be rea-
sonabl y ex pect ed to ca use the failu re of the life support
device or system, or to affect its safety or effectiveness.
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specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer
application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not
designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
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