74F161ASCX Binary Counter 4-Bit Logic IC Equivalent & Substitute Parts

Part Overview

The 74F161ASCX is a 4-bit binary counter logic IC manufactured by onsemi, designed for synchronous counting applications with positive edge triggering. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The 74F161 series provides reliable counting functionality in digital logic circuits with a maximum count rate of 120 MHz and operates across the standard TTL voltage range of 4.5V to 5.5V.

Substiute Parts

74F161ASCX

onsemiIn Stock: 163974F161ASCX Datasheet

Current PartRFQ

SN74F161AD

Texas InstrumentsIn Stock: 2507SN74F161AD Datasheet

DirectRFQ

SN74F161ADR

Texas InstrumentsIn Stock: 3094SN74F161ADR Datasheet

DirectRFQ

SN74F161ANSR

Texas InstrumentsIn Stock: 2892SN74F161ANSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 74F161ASCX are classified based on electrical and mechanical compatibility within the 74F161 series. The substitution logic is determined by the following critical parameters:

Electrical Compatibility Parameters:

• Logic Type: Binary Counter (identical across all substitutes)
• Number of Bits per Element: 4 (identical across all substitutes)
• Direction: Up (identical across all substitutes)
• Reset Type: Asynchronous (identical across all substitutes)
• Timing: Synchronous (identical across all substitutes)
• Trigger Type: Positive Edge (identical across all substitutes)
• Voltage Supply Range: 4.5V ~ 5.5V (identical across all substitutes)
• Operating Temperature: 0°C ~ 70°C (identical across all substitutes)

Mechanical Compatibility Parameters:

• Mounting Type: Surface Mount (identical across all substitutes)
• Package Type: 16-SOIC or 16-SO variants

Performance Consideration:

• Count Rate: Main part rated at 120 MHz; substitute parts rated at 100 MHz (acceptable for most applications within the same series specification)

Substitutes are grouped into two categories: Direct Substitutes (identical package footprint) and Similar Substitutes (compatible package with minor dimensional variation).

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Identical Footprint):

SN74F161ADR (Texas Instruments) is the primary recommended substitute. This part maintains identical electrical specifications and package dimensions (16-SOIC, 0.154", 3.90mm width) as the 74F161ASCX. The part is currently in Active product status with ROHS3 compliance, ensuring long-term availability and regulatory compliance for new designs and production runs.

SN74F161AD (Texas Instruments) is an alternative direct substitute with Last Time Buy status. This part shares identical electrical and mechanical specifications with SN74F161ADR but is available in Tube packaging rather than Tape & Reel format. Selection depends on packaging requirements for assembly processes.

Similar Substitute (Compatible Package Variant):

SN74F161ANSR (Texas Instruments) is a compatible substitute with a wider package body (16-SOIC, 0.209", 5.30mm width). This part maintains all electrical specifications and surface mount compatibility but requires PCB layout verification due to the increased package width. This option is suitable for applications where package width variation is acceptable and does not conflict with board layout constraints.

Selection Criteria:

For new production designs requiring long-term component availability, SN74F161ADR is the optimal choice due to Active product status and ROHS3 compliance. For legacy system maintenance where the original onsemi part is no longer available, any of the three Texas Instruments substitutes provide functional equivalence. Package footprint compatibility must be verified against PCB layout before final selection, particularly for SN74F161ANSR due to its wider body dimension.

Frequently Asked Questions (FAQ)

Q: Can SN74F161ADR be used as a direct replacement for 74F161ASCX on existing PCBs?

A: Yes. SN74F161ADR maintains identical electrical specifications and package footprint (16-SOIC, 0.154", 3.90mm width). No PCB modifications are required for direct substitution.

Q: What is the difference between SN74F161AD and SN74F161ADR?

A: Both parts are electrically and mechanically identical. The difference is packaging format: SN74F161AD is supplied in Tube packaging, while SN74F161ADR is supplied in Tape & Reel format. Selection depends on assembly process requirements and volume needs.

Q: Why is the count rate specification different (120 MHz vs. 100 MHz)?

A: The 74F161ASCX is rated at 120 MHz maximum count rate, while Texas Instruments substitutes are rated at 100 MHz. Both specifications are within the 74F series performance envelope. For applications requiring the full 120 MHz specification, design margin analysis is necessary to confirm 100 MHz operation is acceptable.

Q: Can SN74F161ANSR be used as a substitute if my PCB has limited space?

A: SN74F161ANSR has a wider package body (0.209" vs. 0.154" width). PCB layout must be reviewed to confirm the increased width does not create clearance conflicts with adjacent components or board edge constraints. If space is limited, SN74F161ADR or SN74F161AD are preferred options.

Q: Are all substitute parts RoHS compliant?

A: Yes. All Texas Instruments substitutes (SN74F161AD, SN74F161ADR, SN74F161ANSR) are ROHS3 compliant. The original 74F161ASCX is REACH Unaffected. For applications requiring RoHS compliance, Texas Instruments substitutes are the appropriate choice.

Q: What is the product status significance for component selection?

A: SN74F161ADR has Active status, ensuring continued availability and support. SN74F161AD has Last Time Buy status, indicating limited future availability. For new designs, SN74F161ADR is recommended. For legacy system maintenance, either part is acceptable depending on inventory planning requirements.