SN74ALS666DW

Overview

The SN74ALS666DW 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 SOIC package.

Feature Summary

• Transparent data storage allowing Q outputs to follow D inputs while latch enable is high
• Read-back capability via OERB input to route stored data back onto the input data bus
• 3-state outputs controlled by OE1 and OE2 inputs for bus-structured applications

Applications

• Bus-structured memory systems
• Data storage and buffering
• Input/output interface circuits

Procurement Notes

Verify the specific ordering suffix matches the required package type and lead finish. Confirm RoHS compliance status and moisture sensitivity level ratings against project requirements. Ensure the active production status aligns with long-term availability needs. Check for any specific part marking variations that may affect traceability or identification in final assembly processes.

Selection Notes

Select this component when 8-bit transparent latching with simultaneous read-back functionality is required. The ALS logic family offers faster switching speeds compared to standard LS series. Verify that the 3-state output drive capabilities meet the load requirements of the connected bus lines. Consider the SOIC package dimensions for PCB layout constraints.

Part Context

This device belongs to the SN74ALS66x series of 8-bit D-type transparent read-back latches. It is functionally similar to the SN74ALS667 but provides true (non-inverting) outputs instead of inverted ones. Both variants share identical pinouts and electrical characteristics except for the output polarity.

Replacement Considerations

SN74ALS667DW