DM74ALS652WMX

Overview

The DM74ALS652WMX is an octal 3-STATE bus transceiver and register manufactured by onsemi, utilizing the Advanced Schottky TTL logic series. It integrates an octal transceiver with two independent D-type registers for data storage and transfer between buses or internal memory. The device operates within a supply voltage range of 4.5V to 5.5V and supports a maximum clock frequency of 40 MHz. Propagation delays vary from 5ns to 35ns depending on signal path and load conditions (50pF). It features totem-pole outputs capable of driving low-impedance loads directly without pull-up components. The component is housed in a 24-Lead Small Outline Integrated Circuit (SOIC) package.

Feature Summary

• Integrates an octal bus transceiver with dual independent D-type edge-triggered registers for real-time and stored data selection.
• Features totem-pole 3-STATE outputs designed to drive highly capacitive or low-impedance bus lines directly.
• Includes multiplexed control pins to select between real-time input data and internally stored register data.
• Utilizes advanced oxide-isolated, ion-implanted Schottky TTL process technology.

Applications

• Implementing buffer registers in digital systems
• Configuring I/O ports for microprocessor interfaces
• Serving as bidirectional bus drivers in organized bus architectures
• Functioning as working registers for temporary data storage

Procurement Notes

Verify the specific ordering suffix 'X' confirms tape and reel packaging when sourcing this component. Confirm that the manufacturer designation aligns with current corporate records, as legacy Fairchild Semiconductor products are now managed under onsemi. Ensure compatibility with existing 74ALS logic families regarding voltage levels and interface requirements before integration.

Selection Notes

Select this component for applications requiring simultaneous bidirectional data transfer and storage capabilities within a single integrated circuit. The 3-STATE output capability allows direct connection to system buses without additional buffering hardware. Consider the 24-pin SOIC package constraints for PCB layout and verify that the operating temperature range meets the environmental specifications of the target application.

Part Context

This device belongs to the 74ALS logic family, known for high-speed performance compared to standard TTL. It combines the functionality of a bus transceiver with storage elements, reducing component count in complex digital designs. The octal configuration provides eight parallel data paths, making it suitable for wide data bus implementations in computer and communication systems.

Replacement Considerations

Direct substitutes include the DM74ALS652 without the 'X' suffix for different packaging options. Other compatible devices within the same family include the DM74ALS646 and DM74AS652, though pinouts and specific electrical characteristics should be verified against the original design requirements.

FAQ

How does the device handle transitions between real-time and stored data?

The SAB and SBA control pins allow selection between real-time and stored data using a "make before break" configuration to eliminate glitches during transitions.

What is the maximum clock frequency supported by the DM74ALS652?

The recommended operating conditions specify a maximum clock frequency of 40 MHz.

Can the outputs drive bus lines directly?

Yes, the totem-pole 3-STATE outputs are designed to drive bus lines directly without the need for interface or pull-up components.