SN74LS393NS Equivalent & Substitute Parts

Part Overview

The SN74LS393NS is a binary counter IC manufactured by Texas Instruments, classified as a Logic component in the 74LS series. This device functions as a 2-element, 4-bit binary counter with negative edge triggering and asynchronous reset capability. The part is designated as Last Time Buy status, indicating it is no longer in active production. Finding equivalent substitute parts is necessary to ensure continued availability for new designs, maintenance applications, and production continuity.

Substiute Parts

SN74LS393NS

Texas InstrumentsIn Stock: 1708SN74LS393NS Datasheet

Current PartRFQ

SN74LS393NSR

Texas InstrumentsIn Stock: 3579SN74LS393NSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS393NS is determined by strict equivalence across the following critical parameters:

• Logic Type: Binary Counter (2 Element, 4 Bit configuration)
• Trigger Type: Negative Edge
• Reset Type: Asynchronous
• Count Rate: 35 MHz minimum
• Voltage Supply Range: 4.75 V ~ 5.25 V
• Package / Case: 14-SOIC form factor
• Mounting Type: Surface Mount
• Operating Temperature Range: 0°C ~ 70°C

The SN74LS393NSR qualifies as a direct substitute because it maintains identical electrical specifications, functional characteristics, and physical packaging. The primary difference is packaging format (Cut Tape & Digi-Reel versus Tube) and product status (Active versus Last Time Buy).

Parameter Comparison

Engineering Selection Recommendations

The SN74LS393NSR is the manufacturer-recommended substitute for the SN74LS393NS. Selection between these parts should be based on the following criteria:

SN74LS393NS (Last Time Buy): Use only for replacement or repair of existing assemblies where the original part number must be maintained for traceability or documentation purposes. Inventory is limited to 1,641 pieces.

SN74LS393NSR (Active): Recommended for all new designs and production applications. This part maintains full electrical and functional equivalence while offering Active product status and greater availability (3,486 pieces in stock). Both parts are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

The packaging format difference (Tube versus Cut Tape & Digi-Reel) does not affect electrical performance or PCB assembly compatibility. Selection should be based on procurement requirements and supply chain considerations.

Frequently Asked Questions (FAQ)

Q: Can SN74LS393NSR be used as a direct replacement for SN74LS393NS in existing designs?

A: Yes. The SN74LS393NSR is electrically and functionally identical to the SN74LS393NS. All electrical parameters, timing specifications, and package dimensions are equivalent. The parts are pin-for-pin compatible and require no circuit modifications.

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

A: Tube packaging is used for lower-volume orders and manual assembly processes. Cut Tape & Digi-Reel packaging is used for automated pick-and-place assembly and higher-volume production. Both formats contain the same component with identical electrical specifications. The packaging format does not affect component performance or reliability.

Q: Why is SN74LS393NS marked as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued active production of this part number. Existing inventory is available for a limited time. The SN74LS393NSR remains in active production and is the recommended alternative for new applications.

Q: Are there any compliance or certification differences between these parts?

A: No. Both SN74LS393NS and SN74LS393NSR are ROHS3 compliant, REACH unaffected, and carry identical environmental and regulatory certifications. Both parts meet the same quality and reliability standards.

Q: What is the operating temperature range for these parts?

A: Both parts operate within the range of 0°C to 70°C (TA). This specification applies to both the SN74LS393NS and SN74LS393NSR and must be verified against your application requirements.

Q: Can these parts be used in applications requiring higher count rates?

A: No. Both parts are specified for a maximum count rate of 35 MHz. Applications requiring higher frequency operation require alternative components with higher count rate specifications.