74F161ASC Binary Counter IC Equivalent & Substitute Parts

Part Overview

The 74F161ASC is a 4-bit binary counter IC manufactured by onsemi, housed in a 16-SOIC package. This component functions as a synchronous counter with asynchronous reset, designed for digital logic applications requiring counting operations at high speed. The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Specification
Logic Type	Binary Counter
Number of Bits per Element	4 Bit
Number of Elements	1
Direction	Up
Reset Type	Asynchronous
Timing	Synchronous
Trigger Type	Positive Edge
Count Rate	120 MHz
Voltage Supply Range	4.5 V ~ 5.5 V
Operating Temperature	0°C ~ 70°C
Package / Case	16-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Series	74F

Substitute Part Grouping Explanation

Substitute parts for the 74F161ASC are classified based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

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

Direct substitutes maintain all electrical parameters and package compatibility. Similar substitutes maintain all electrical parameters but differ in package dimensions, requiring PCB layout evaluation.

Parameter Comparison

Parameter	74F161ASC (onsemi)	SN74F161AD (TI)	SN74F161ADR (TI)	SN74F161ANSR (TI)
Manufacturer	onsemi	Texas Instruments	Texas Instruments	Texas Instruments
Product Status	Obsolete	Last Time Buy	Active	Active
Logic Type	Binary Counter	Binary Counter	Binary Counter	Binary Counter
Number of Bits	4 Bit	4 Bit	4 Bit	4 Bit
Direction	Up	Up	Up	Up
Reset Type	Asynchronous	Asynchronous	Asynchronous	Asynchronous
Timing	Synchronous	Synchronous	Synchronous	Synchronous
Trigger Type	Positive Edge	Positive Edge	Positive Edge	Positive Edge
Count Rate	120 MHz	100 MHz	100 MHz	100 MHz
Voltage Supply	4.5 V ~ 5.5 V	4.5 V ~ 5.5 V	4.5 V ~ 5.5 V	4.5 V ~ 5.5 V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Package / Case	16-SOIC (0.154", 3.90mm)	16-SOIC (0.154", 3.90mm)	16-SOIC (0.154", 3.90mm)	16-SOIC (0.209", 5.30mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Packaging	Not specified	Tube	Tape & Reel (TR)	Tape & Reel (TR)
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Substitutes (Preferred):

SN74F161ADR (Texas Instruments) is the recommended primary substitute. This part maintains active product status, ensuring long-term availability and supply chain stability. It is ROHS3 compliant and supplied in Tape & Reel packaging, suitable for automated assembly processes. All electrical parameters and package dimensions are identical to the 74F161ASC.

SN74F161AD (Texas Instruments) serves as a secondary direct substitute with identical electrical and package specifications. This part carries Last Time Buy status, indicating limited future availability. It is supplied in Tube packaging, appropriate for manual assembly or lower-volume applications.

Similar Substitute (Package Variation):

SN74F161ANSR (Texas Instruments) maintains all electrical compatibility but differs in package width (0.209" versus 0.154"). This part is active and ROHS3 compliant. Selection requires PCB layout verification to accommodate the larger package footprint.

All substitute parts are manufactured by Texas Instruments, a primary source manufacturer in the 74F logic family, ensuring design continuity and reliability.

Frequently Asked Questions (FAQ)

Q: Can SN74F161ADR directly replace 74F161ASC without PCB modifications?

A: Yes. SN74F161ADR maintains identical electrical specifications and package dimensions (16-SOIC, 0.154" width). No PCB layout changes are required for direct substitution.

Q: What is the difference between SN74F161AD and SN74F161ADR?

A: Both parts are electrically identical with the same package dimensions. The primary difference is packaging format: SN74F161AD is supplied in Tube, while SN74F161ADR is supplied in Tape & Reel. Selection depends on assembly process requirements and volume.

Q: Why does SN74F161ANSR have a different package width?

A: SN74F161ANSR uses a 16-SO package (0.209" width) compared to the 16-SOIC package (0.154" width) of the original part. This represents a different package variant within the same logic family. PCB footprint compatibility must be verified before selection.

Q: Is the count rate difference between 120 MHz and 100 MHz significant for substitution?

A: The 74F161ASC specifies 120 MHz maximum count rate, while Texas Instruments substitutes specify 100 MHz. For applications operating below 100 MHz, substitution is valid. Applications requiring operation above 100 MHz require design review.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. SN74F161AD, SN74F161ADR, and SN74F161ANSR are all ROHS3 compliant. The original 74F161ASC RoHS status is not specified in available documentation.

Q: Which substitute part offers the best long-term availability?

A: SN74F161ADR (Active status) and SN74F161ANSR (Active status) both offer active product status, ensuring continued availability. SN74F161AD carries Last Time Buy status, indicating limited future procurement windows.

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