DM74LS279N

Latches Overview

The DM74LS279N is a quad S-R latch integrated circuit manufactured by onsemi, formerly Fairchild Semiconductor. It operates within a supply voltage range of 4.75V to 5.25V and features four independent latches with active-low inputs. Two latches include an additional Set input ANDed with the primary Set input. The device utilizes a 16-lead Plastic Dual-In-Line (PDIP) package. Propagation delays from Set to Q range from 15ns to 25ns, while Reset to Q transitions occur between 27ns and 33ns at 5V.

Latches Feature Summary

• Contains four independent Set-Reset latches with active-low inputs for data storage
• Includes two latches with dual Set inputs where both must be HIGH to set the latch
• Voltage level triggered inputs unaffected by transition time of input data
• Outputs maintain state until overridden by valid Set or Reset signals

Latches Applications

• General-purpose digital logic circuits requiring memory storage elements
• Data buffering applications in microprocessor systems
• Control logic interfaces for industrial automation equipment
• Status register implementations in embedded hardware designs

Latches Procurement Notes

Verify that the ordering code matches the specific package variant required, as devices are also available in Tape and Reel formats specified by appending the suffix letter X. Confirm the manufacturer origin, noting historical production by Fairchild Semiconductor prior to acquisition by onsemi. Ensure compliance with RoHS standards applicable to the manufacturing date. Check for life support restrictions if the application involves critical safety systems.

Latches Selection Notes

Select this component when designing circuits requiring multiple independent latches with active-low control signals. Consider the dual Set input feature on two channels for complex logic gating requirements. Evaluate propagation delay specifications against system timing constraints, particularly for high-speed signal processing. Verify operating temperature range compatibility with the intended environmental conditions.

Latches Part Context

This component belongs to the 74LS series of logic integrated circuits, known for low-power Schottky technology. It provides a cost-effective solution for implementing basic memory functions in digital systems. The PDIP package facilitates through-hole mounting for prototyping and legacy board designs. It serves as a fundamental building block for sequential logic circuits requiring stable state retention.

Latches Replacement Considerations

Direct substitutes include SN74LS279AN from Texas Instruments and other 74LS279 variants from different manufacturers. Verify pinout compatibility and electrical characteristics before substitution. Ensure the replacement part supports the same active-low input logic and dual Set input functionality if required by the design.