CD74HC640E

Overview

The CD74HC640E is an octal bus transceiver manufactured by Texas Instruments, belonging to the HC logic family. It features eight bidirectional data channels with three-state outputs and inverting polarity. The device operates within a supply voltage range of 2 V to 6 V and supports low-level output currents of 7.8 mA and high-level output currents of -7.8 mA. It exhibits a propagation delay of 90 ns and maintains a maximum power supply current of 8 uA. The component is housed in a PDIP-20 package and functions reliably across an extended temperature range from -55 °C to +125 °C.

Feature Summary

• Provides bidirectional data transmission through eight independent channels with inverted logic polarity.
• Features three-state outputs that allow direct connection to bus lines without external drivers.
• Utilizes silicon gate CMOS technology for low power consumption while maintaining high-speed performance.

Applications

• Memory module address and data bus driving
• Clock distribution circuits
• Bidirectional data buffering

Procurement Notes

Verify the specific suffix 'E' confirms the PDIP-20 through-hole package variant when sourcing. Ensure the order specifies the standard commercial or industrial grade requirements matching the -55 °C to +125 °C operating range. Confirm RoHS compliance status directly with the manufacturer documentation prior to final procurement decisions.

Selection Notes

Select this component for designs requiring robust bidirectional data transfer between microprocessors and peripheral devices. The wide 2 V to 6 V supply range offers flexibility for various logic families. The inverting configuration must be accounted for in signal path design. Consider the PDIP-20 package constraints if surface mount space is limited.

Part Context

This part belongs to the SN74HC640 series of octal bus transceivers. It shares functional similarities with the CD74HC540, though the latter lacks bidirectional capability. The device is part of the broader 74HC logic family, designed to replace older TTL technologies with lower power consumption and higher noise immunity characteristics suitable for modern digital systems.

Replacement Considerations

SN74HC640N (PDIP-20 variant)

FAQ

Is the CD74HC640E compatible with 3.3 V logic levels?

Yes, the device operates within a supply voltage range of 2 V to 6 V, making it compatible with 3.3 V logic systems.

What is the output configuration of this transceiver?

The CD74HC640E features three-state outputs with inverting polarity, allowing for controlled bus isolation.