Datasheet

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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 LVX4245 is a dual-supply, 8-bit translating transceiver

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; Receive (active-LOW) enables data from 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 threshold performance

■ Implements patented EMI reduction circuitry

■ Functionally compatible with the 74 series 245

Ordering Code:

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Logic Symbol

Connection Diagram

Pin Descriptions

Truth Table

H = HIGH Voltage Level

L = LOW Voltage Level

X = Immaterial

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 Names Description

Output Enable Input

T/R

Transmit/Receive Input

–A

Side A Inputs or 3-STATE Outputs

–B

Side B Inputs or 3-STATE Outputs

Inputs Outputs

T/R

L L Bus B Data to Bus A

L H Bus A Data to Bus B

H X HIGH-Z State

Summary of content (8 pages)

PAGE 1
Revised September 2003 74LVX4245 8-Bit Dual Supply Translating Transceiver with 3-STATE Outputs General Description Features The LVX4245 is a dual-supply, 8-bit translating transceiver 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; Receive (active-LOW) enables data from B Ports to A Ports.
PAGE 2
74LVX4245 Logic Diagram www.fairchildsemi.
PAGE 3
Supply Voltage (VCCA, VCCB) DC Input Voltage (VI) @ OE, T/R Recommended Operating Conditions (Note 2) −0.5V to +7.0V −0.5V to VCCA + 0.5V Supply Voltage DC Input/Output Voltage (VI/O ) @ An −0.5V to VCCA + 0.5V @Bn −0.5V to VCCB + 0.5V 4.5V to 5.5V VCCB 2.7V to 3.
PAGE 4
74LVX4245 DC Electrical Characteristics Symbol ICCA Parameter (Continued) VCCA VCCB (V) (V) 5.5 3.6 TA +25°C TA = −40°C to +85°C Typ Units An = VCCA or GND Quiescent VCCA Supply Current Conditions Guaranteed Limits 8 80 µA Bn = VCCB or GND, OE = GND T/R = GND ICCB An = VCCA or GND Quiescent VCCB Supply Current 5.5 3.6 5 50 VOLPA Quiet Output Maximum 5.0 3.3 1.5 VOLPB Dynamic VOL 5.0 3.3 0.8 VOLVA Quiet Output Minimum 5.0 3.3 −1.2 VOLVB Dynamic VOL 5.0 3.3 −0.
PAGE 5
74LVX4245 Capacitance Symbol CIN CI/O Typ Units Conditions Input Capacitance Parameter 4.5 pF VCC = Open Input/Output 15 pF VCCA = 5.0V VCCB = 3.3V Capacitance CPD Power Dissipation B→A 55 pF VCCA = 5.0V Capacitance (Note 10) A→B 40 pF VCCB = 3.3V Note 10: CPD is measured at 10 MHz 8-Bit Dual Supply Translating Transceiver The LVX4245 is a dual supply device capable of bidirectional signal translation.
PAGE 6
74LVX4245 Applications: Mixed Mode Dual Supply Interface Solution either a 3V system or a 5V system without any further work to re-layout the board. LVX4245 is designed to solve 3V/5V interfacing issues when CMOS devices cannot tolerate I/O levels above their 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.
PAGE 7
4LVX4245 Physical Dimensions 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 7 www.fairchildsemi.
PAGE 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 assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications.