74F161ASJX Binary Counter 4-Bit Logic IC Equivalent & Substitute Parts

Part Overview

The 74F161ASJX is a 4-bit binary counter logic IC manufactured by onsemi, housed in a 16-SOP surface mount package. This component functions as a synchronous binary counter with asynchronous reset, capable of counting at 120 MHz with positive edge triggering. The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts maintain functional equivalence while offering improved availability and product status through active manufacturers.

Substiute Parts

74F161ASJX

onsemiIn Stock: 443574F161ASJX Datasheet

Current PartRFQ

SN74F161ANSR

Texas InstrumentsIn Stock: 2892SN74F161ANSR Datasheet

DirectRFQ

SN74F161AD

Texas InstrumentsIn Stock: 2507SN74F161AD Datasheet

SimilarRFQ

SN74F161ADR

Texas InstrumentsIn Stock: 3094SN74F161ADR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 74F161ASJX are qualified based on the following criteria:

Functional Parameters (Must Match):

• Logic Type: Binary Counter
• Number of Bits per Element: 4
• Number of Elements: 1
• Direction: Up
• Reset Type: Asynchronous
• Timing: Synchronous
• Trigger Type: Positive Edge
• Voltage Supply Range: 4.5 V ~ 5.5 V
• Operating Temperature Range: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Series: 74F

Allowed Variations:

• Count Rate: Substitute parts may operate at equal or higher frequency (100 MHz minimum acceptable)
• Package / Case: Different SOIC widths permitted (0.209" or 0.154") while maintaining 16-pin SOIC configuration
• Packaging Format: Tape & Reel or Tube acceptable for surface mount applications
• Product Status: Active or Last Time Buy status preferred over obsolete

All substitute parts listed maintain electrical and functional equivalence within these parameters.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SN74F161ADR (Texas Instruments)

The SN74F161ADR is the preferred substitute for the 74F161ASJX. This part maintains active product status with Texas Instruments, ensuring long-term availability and supply chain stability. It is ROHS3 compliant and carries REACH Unaffected certification. The 16-SOIC (0.154", 3.90mm) package is a standard form factor for modern surface mount assembly. Tape & Reel packaging supports automated production environments.

Secondary Recommendation: SN74F161ANSR (Texas Instruments)

The SN74F161ANSR provides an alternative with identical electrical specifications and active product status. This variant uses the 16-SOIC (0.209", 5.30mm) package, matching the original 74F161ASJX package width. This option is suitable for designs where PCB layout or assembly tooling is optimized for the wider SOIC footprint. Tape & Reel packaging is standard for high-volume applications.

Tertiary Option: SN74F161AD (Texas Instruments)

The SN74F161AD is functionally equivalent but carries Last Time Buy status, indicating limited future availability. This part should be selected only when existing inventory or design constraints require the 16-SOIC (0.154", 3.90mm) package and Tube packaging format. Tube packaging is suitable for lower-volume or manual assembly processes.

Selection Criteria Summary:

• All substitute parts maintain functional equivalence across all critical parameters
• Count rate reduction from 120 MHz to 100 MHz is within acceptable operating margins for 74F series logic applications
• Package width variation (0.209" vs 0.154") requires PCB layout verification but does not affect electrical performance
• Active product status (SN74F161ADR, SN74F161ANSR) ensures supply continuity
• ROHS3 compliance of all Texas Instruments variants supports environmental and regulatory requirements

Frequently Asked Questions (FAQ)

Q: Can the SN74F161ADR directly replace the 74F161ASJX without circuit modifications?

A: Yes. The SN74F161ADR maintains electrical equivalence across all functional parameters including logic type, bit width, reset behavior, timing characteristics, voltage supply range, and operating temperature range. The 100 MHz count rate is sufficient for applications designed for the 120 MHz original part. PCB layout must accommodate the 16-SOIC (0.154", 3.90mm) package footprint.

Q: What is the difference between the 16-SOIC (0.209") and 16-SOIC (0.154") packages?

A: Both are 16-pin SOIC packages with identical pin pitch and electrical characteristics. The dimension refers to package width. The 0.209" width (SN74F161ANSR) matches the original 74F161ASJX footprint. The 0.154" width (SN74F161AD, SN74F161ADR) is a narrower variant. PCB design and assembly equipment must support the selected package width. Electrical performance is identical.

Q: Why does the SN74F161ADR have a lower count rate (100 MHz vs 120 MHz)?

A: The 100 MHz specification for Texas Instruments parts represents the guaranteed maximum operating frequency under specified conditions. The 20 MHz difference does not affect functional equivalence for standard 74F series logic applications. Applications operating below 100 MHz experience no performance impact.

Q: Is the SN74F161AD suitable for new designs?

A: The SN74F161AD carries Last Time Buy status, indicating limited future availability. For new designs, SN74F161ADR or SN74F161ANSR are preferred to ensure long-term supply chain stability and support. SN74F161AD is appropriate only for legacy system maintenance or when existing inventory is available.

Q: What packaging format should I select for automated assembly?

A: Tape & Reel (TR) packaging is standard for automated surface mount assembly. Both SN74F161ANSR and SN74F161ADR are available in Tape & Reel format. Tube packaging (SN74F161AD) is suitable for manual or semi-automated processes with lower volume requirements.

Q: Are all substitute parts RoHS compliant?

A: All Texas Instruments substitute parts (SN74F161ANSR, SN74F161AD, SN74F161ADR) are ROHS3 compliant. The original 74F161ASJX RoHS status is not specified. ROHS3 compliance ensures compatibility with environmental and regulatory requirements for modern electronics manufacturing.

Q: Can I use these parts interchangeably in existing PCB designs?

A: Interchangeability depends on package selection. SN74F161ANSR uses the 0.209" SOIC width matching the original 74F161ASJX and can be used as a direct footprint replacement. SN74F161AD and SN74F161ADR use the 0.154" SOIC width and require PCB layout verification to confirm footprint compatibility. Pin assignments are identical across all variants.