SN74ALS990NG4

Overview

The SN74ALS990NG4 is an octal D-type transparent read-back latch manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and supports a propagation delay of 6 ns. The device features low-level output current of 8 mA and high-level output current of -400 µA. It is characterized for operation from 0°C to 70°C and utilizes a 20-pin PDIP package.

Feature Summary

• Octal D-type transparent latch architecture designed for storing input data bus contents
• Read-back capability allowing internal state verification without external feedback loops
• Tri-state outputs enabling direct connection to system buses

Applications

• Data storage in microprocessor-based systems
• Bus interface buffering applications
• Digital logic circuit design requiring parallel data retention

Procurement Notes

Verify the specific suffix 'G4' indicates RoHS compliance and green manufacturing status as per Texas Instruments documentation. Confirm the 20-PDIP package dimensions match your PCB footprint requirements. Ensure the operating temperature range of 0°C to 70°C aligns with your environmental specifications before finalizing procurement.

Selection Notes

Select this component when an octal latch with tri-state outputs and read-back functionality is required. It is suitable for designs needing high-speed data latching with a 6 ns propagation delay. Consider the through-hole mounting requirement associated with the PDIP package when choosing between surface mount and leaded options.

Part Context

This part belongs to the SN74ALS series, representing Advanced Low-power Schottky logic technology. It serves as a digital storage element within the broader family of Texas Instruments logic integrated circuits, providing reliable data retention for digital systems.

Replacement Considerations

Check for SN74ALS990N as a potential equivalent variant. Verify pin compatibility and electrical characteristics against the original datasheet before substitution.