SN74ALS666DWE4

Overview

The SN74ALS666DWE4 is an 8-bit D-type transparent read-back latch with 3-state outputs manufactured by Texas Instruments. It belongs to the ALS logic series and operates within a supply voltage range of 4.5 V to 5.5 V. The device features true outputs, preset and clear inputs, and dual output enables. It supports bus-structured applications through its I/O-type read-back capability. The component is housed in a 24-pin Small-Outline (DW) package and is characterized for operation from 0°C to 70°C.

Feature Summary

• Provides 8-bit data storage with transparent latching functionality when the latch enable signal is active.
• Includes a read-back control input that routes stored data back onto the input data bus for verification.
• Features 3-state outputs controlled by separate enable inputs to facilitate bus-driven architectures.

Applications

• Bus-structured memory systems
• Data storage registers
• I/O interface circuits

Procurement Notes

Verify the specific ordering suffix 'E4' against current manufacturer documentation to confirm compliance details. Confirm the package type matches the required PCB footprint. Ensure the operating temperature range aligns with the system environment. Check for any recent lifecycle status changes or obsolescence notices before finalizing procurement plans.

Selection Notes

Select this component for designs requiring 8-bit latching with direct data read-back capabilities. The ALS series offers a balance of speed and power consumption suitable for standard digital logic applications. Consider the 3-state output configuration if multiple devices share a common data bus structure.

Part Context

This part is part of the SN74ALS666/667 family of 8-bit latches. The SN74ALS666 variant provides true outputs, while the SN74ALS667 provides inverted outputs. Both share identical pinouts and functional characteristics except for the output polarity. The DW package indicates a surface-mount small-outline form factor.

Replacement Considerations

SN74ALS666DW serves as a direct equivalent without the environmental suffix. SN74ALS667DW is functionally similar but provides inverted outputs instead of true outputs.