SN74LS123NS Equivalent & Substitute Parts

Part Overview

The SN74LS123NS is a monostable multivibrator logic integrated circuit manufactured by Texas Instruments. This device features two independent circuits with a propagation delay of 34 ns and operates within the standard TTL voltage supply range of 4.75 V to 5.25 V. The part is packaged in a 16-SOIC surface mount configuration and is classified as discontinued at DiGi Electronics, making identification of compatible alternatives essential for ongoing design support and procurement.

Substiute Parts

SN74LS123NS

Texas InstrumentsIn Stock: 7514SN74LS123NS Datasheet

Current PartRFQ

SN74LS123NSR

Texas InstrumentsIn Stock: 4542SN74LS123NSR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS123NS is determined by the following critical parameters:

• Logic type and circuit configuration (monostable multivibrator with 2 independent circuits)
• Package and case specification (16-SOIC surface mount)
• Electrical characteristics (supply voltage range, output current ratings)
• Propagation delay performance (34 ns baseline)
• Compliance certifications (RoHS3, REACH status)

The SN74LS123NSR qualifies as a direct substitute based on matching all core functional and physical parameters. The primary distinction is packaging format (Tape & Reel versus Tube) and a faster propagation delay specification (28 ns versus 34 ns), which represents improved performance within the same electrical envelope.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS123NSR is the direct substitute for the SN74LS123NS. Both parts maintain identical electrical specifications, package geometry, and compliance certifications. The SN74LS123NSR offers the advantage of active product status with current manufacturing availability, whereas the SN74LS123NS is discontinued. The faster propagation delay of the SN74LS123NSR (28 ns) provides performance margin without compromising compatibility. Selection between these parts should be based on procurement requirements and packaging format preference (Tube versus Tape & Reel).

Frequently Asked Questions (FAQ)

Q: Can the SN74LS123NSR replace the SN74LS123NS in existing designs?

A: Yes. Both parts share identical package geometry (16-SOIC), electrical characteristics (supply voltage, output current), and functional specifications (monostable multivibrator with 2 independent circuits). The SN74LS123NSR operates with faster propagation delay (28 ns versus 34 ns), which is compatible with designs specified for the original part.

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging (SN74LS123NS) is used for lower-volume orders and manual handling. Tape & Reel packaging (SN74LS123NSR) is designed for automated assembly processes and higher-volume production. Both formats contain identical die and electrical performance.

Q: Are both parts RoHS3 compliant?

A: Yes. Both the SN74LS123NS and SN74LS123NSR are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Why is the SN74LS123NS listed as discontinued?

A: The SN74LS123NS is discontinued at DiGi Electronics. The SN74LS123NSR remains in active production and is the recommended source for new procurement.

Q: Does the faster propagation delay of the SN74LS123NSR affect circuit operation?

A: No. The 28 ns propagation delay of the SN74LS123NSR is faster than the 34 ns specification of the SN74LS123NS. Designs specified for 34 ns will operate correctly with the faster part, as timing margins are maintained or improved.