SN74ALS870DW

Overview

The SN74ALS870DW is a dual 16-word by 4-bit register file in a 24-pin SOIC package. It operates on a supply voltage of 4.5 V to 5.5 V with an operating temperature range of 0°C to 70°C. The device features two independent register files, each with individual write-enable controls and address lines. It includes two 4-bit data I/O ports (DQA and DQB) with 3-state buffer-type outputs designed to drive bus lines directly.

Feature Summary

• Features two 16-word by 4-bit register files with individual write-enable controls and address lines for independent operation.
• Includes two 4-bit data I/O ports capable of input/output configurations to support bus A and bus B connections.
• Outputs are 3-state buffer-type designs intended to drive bus lines directly without additional buffering.

Applications

• Multibus architecture systems
• Overlapping file operations
• Dual-input mode applications requiring prioritized B-input port

Procurement Notes

Verify the specific ordering suffix (e.g., DW, DWR, NSR) against the datasheet packaging information to confirm pin count, package type, and reel quantity. Ensure the component status is listed as ACTIVE for new designs. Confirm RoHS compliance and lead finish details match project requirements before finalizing procurement orders.

Selection Notes

Select this component when a design requires two separate 16x4 memory banks accessible via distinct control lines. The ALS logic family provides specific switching characteristics suitable for standard TTL-compatible interfaces. Verify that the required number of address lines and write enables aligns with the available pins on the chosen package variant.

Part Context

This device belongs to the Texas Instruments SN74ALS series of logic components. It functions as a specialized memory interface element rather than a standard gate or flip-flop. The dual register file structure allows for complex data routing between multiple buses within a single integrated circuit package.

Replacement Considerations

SN74ALS870DWE4

FAQ

How does the device handle write conflicts during dual-input mode?

The B-input port takes priority over the A-input port to prevent writing conflicts when both inputs are active simultaneously.

What is the function of the S0, S1, S2, and S3 select lines?

S0 and S1 determine which register file has access to which port. S2 controls whether the A ports are in input or output modes, while S3 performs the same function for the B ports.