MC74VHC245DTR2G

Overview

The MC74VHC245DTR2G is an octal bidirectional transceiver manufactured by onsemi, belonging to the 74VHC logic family. It operates within a supply voltage range of 2.0 V to 5.5 V and features three-state outputs. The device provides balanced propagation delays with a typical value of 4.0 ns at VCC = 5.0 V. It supports output currents of ±8 mA and maintains low static power consumption with maximum ICC of 4.0 µA at 25°C. The component is housed in a TSSOP-20 surface-mount package and is designed for high-speed data bus applications.

Feature Summary

• Provides high-speed bidirectional data transmission between two buses with balanced propagation delays.
• Features five-volt tolerant inputs and outputs, enabling safe interfacing with 5 V devices even when operating at lower supply voltages.
• Includes IOFF support to guarantee high-impedance states during power-off conditions, preventing back-driving on the data bus.

Applications

• Memory address driving in computing systems
• TTL level bus oriented transceiver applications
• High-speed data bus communication interfaces

Procurement Notes

Verify the specific suffix DTR2G against the manufacturer's current datasheet to confirm the tape-and-reel packaging configuration and lead-free status. Ensure the ordering part number matches the required RoHS compliance and automotive qualification requirements if applicable. Cross-reference the pinout diagram with the target PCB footprint to avoid assembly errors due to package variations.

Selection Notes

Select this component when designing systems requiring interface between 3.3 V and 5.0 V logic domains without external level shifters. The VHC series offers superior speed compared to standard HC or AC families while maintaining CMOS compatibility. Consider the ±8 mA drive capability for moderate capacitive loads and verify that the 2.0 V minimum supply meets the lowest system voltage requirement.

Part Context

This device is part of the MC74VHC245/MC74VHCT245A family of octal bus transceivers. While the VHCT variant utilizes TTL-compatible inputs for direct interfacing with legacy logic, the VHC version employs CMOS-compatible inputs. Both variants share the same physical package and functional direction control, differing primarily in input threshold characteristics and noise immunity profiles.

Replacement Considerations

MC74LCX245DTR2G: Offers similar functionality but with LVC technology and different electrical characteristics. MC74AC245DWR2G: Provides AC family performance with wider voltage tolerance but distinct pinout or parameter differences may require schematic review.

FAQ

What is the typical propagation delay for the MC74VHC245DTR2G?

The typical propagation delay (tPD) is 4.0 ns when operating at a supply voltage (VCC) of 5.0 V.

How does the IOFF feature benefit the circuit design?

The IOFF specification guarantees that the outputs enter a high-impedance state when VCC is 0 V, which prevents the device from back-driving the bus during power-down or hot-swap scenarios.