MC74LVX245M

Overview

The MC74LVX245 is an advanced high-speed CMOS octal bus transceiver designed for two-way asynchronous communication between data buses. It operates within a DC supply voltage range of 2.0 V to 3.6 V and features 5 V-tolerant inputs, allowing compatibility with 5 V systems. The device includes power-down protection on inputs and balanced propagation delays. Key electrical characteristics include a typical propagation delay (tPD) of 4.7 ns at VCC = 3.3 V and a maximum quiescent supply current (ICC) of 40 µA at TA = 85 °C.

Feature Summary

• Provides bidirectional data transmission controlled by the T/R input signal level.
• Features 5 V-tolerant inputs suitable for interfacing with different logic families.
• Includes output enable functionality to isolate buses when disabled.
• Offers power-down protection on all inputs against static discharge.

Applications

• Asynchronous communication between data buses
• Voltage level translation between 3.3 V and 5 V systems
• Bus-oriented memory and driver applications

Procurement Notes

Verify the specific package suffix required for your design, such as DWR2G for SOIC-20 or DTR2G for TSSOP-20, as these determine shipping quantities and reel specifications. Confirm that the selected variant meets the moisture sensitivity level requirements for your assembly process. Ensure that the ordering information matches the exact marking diagram needed for traceability in your manufacturing workflow.

Selection Notes

Select this component when designing systems requiring low-power, high-speed bidirectional data transfer between 3.3 V and 5 V domains. Consider the 5 V tolerance of the inputs if interfacing directly with legacy 5 V logic without additional level shifting circuitry. Evaluate the package options based on available board space and thermal dissipation needs, keeping in mind the maximum operating temperature range of -40 °C to +85 °C.

Part Context

This part belongs to the LVX series of advanced high-speed CMOS logic devices from onsemi. It is functionally compatible with other standard logic families but optimized for lower voltage operation compared to traditional HC or HCT families. The device serves as a core interface solution in digital systems where data integrity and speed are critical across mixed-voltage environments.

Replacement Considerations

Direct pin-compatible replacements may exist within the same LVX family or from other manufacturers offering equivalent octal bus transceivers. Verify that any substitute maintains the 5 V input tolerance and similar propagation delay characteristics to ensure system timing compliance.

FAQ

Can the MC74LVX245 be used to interface 5.0 V to 3.0 V systems directly?

No, a parasitic diode is formed between the bus and VCC terminals, preventing direct interface between 5.0 V and 3.0 V systems.

What happens if inputs are left floating?

All floating (high impedance) input or I/O pins must be fixed by means of pullup or pulldown resistors or bus terminator ICs to prevent undefined states.

How is the direction of data transmission determined?

The direction is determined by the level of the T/R input; a low level directs data from B to A, while a high level directs data from A to B.