SN74ALS666DWG4

Overview

The SN74ALS666DWG4 is an 8-bit D-type transparent read-back latch with 3-state outputs manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature from 0°C to 70°C. The device features a propagation delay of up to 18 ns, low-level output current of 24 mA, and high-level output current of -2.6 mA. It utilizes a 24-pin Small-Outline (SOIC) package.

Feature Summary

• Provides I/O-type read-back inputs allowing stored data to be routed back onto the input data bus via the OERB control signal.
• Features a bus-structured pinout design suitable for efficient integration into bus-based system architectures.
• Includes dedicated preset and clear inputs for direct control over latch states independent of data inputs.

Applications

• Bus-structured applications requiring data storage and retrieval
• Systems utilizing 3-state buffer-type outputs for shared data lines
• Digital circuits needing transparent latching with read-back capability

Procurement Notes

Verify that the ordering suffix 'G4' corresponds to RoHS compliance and lead finish specifications as defined in the official packaging addendum. Confirm the SOIC-24 package dimensions and tube quantity match your assembly requirements. Ensure the component status remains active production before finalizing procurement plans.

Selection Notes

Select this component when an 8-bit transparent latch with read-back functionality is required. The ALS series offers specific speed and power characteristics compared to standard TTL. Verify that the 3-state output configuration aligns with the bus architecture needs of the target application design.

Part Context

This part belongs to the SN74ALS666/667 family of 8-bit D-type transparent read-back latches. The SN74ALS666 variant provides true outputs, whereas the SN74ALS667 provides inverted outputs. Both share identical pinouts and functional descriptions except for the output polarity.

Replacement Considerations

SN74ALS666DW is the non-G4 equivalent offering identical electrical and mechanical specifications without the G4 suffix designation.