SA64ALF Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The SA64ALF is a unidirectional Zener-type transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in through-hole axial configurations. This component features a 64V reverse standoff voltage with a 103V maximum clamping voltage and 4.9A peak pulse current capability. The SA64ALF is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement.

Substiute Parts

SA64ALF

onsemiIn Stock: 1046SA64ALF Datasheet

Current PartRFQ

SA64A

Taiwan Semiconductor CorporationIn Stock: 3436SA64A Datasheet

DirectRFQ

1N8172

Microchip TechnologyIn Stock: 7271N8172 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SA64ALF is determined by strict alignment across the following critical parameters:

• Voltage - Reverse Standoff (Typ): 64V
• Voltage - Clamping (Max) @ Ipp: 103V
• Type: Zener, Unidirectional
• Mounting Type: Through Hole
• Package / Case: Axial or DO-204AC (DO-15) compatible

The SA64A qualifies as a direct manufacturer substitute, maintaining identical voltage specifications and clamping characteristics while offering improved product status (Active) and RoHS3 compliance. The 1N8172 qualifies as a similar substitute, meeting core voltage parameters but with reduced peak pulse current (1.45A versus 4.9A) and lower peak pulse power (150W versus 500W).

Parameter Comparison

Engineering Selection Recommendations

The SA64A represents the primary substitute for the obsolete SA64ALF. Both components share identical voltage specifications (64V standoff, 103V clamping) and equivalent peak pulse ratings (5A versus 4.9A). The SA64A offers superior product status (Active), extended operating temperature range (-55°C to 175°C versus -55°C to 150°C), and RoHS3 compliance, making it the preferred choice for new designs and long-term availability.

The 1N8172 from Microchip Technology qualifies as a secondary substitute when peak pulse current and power dissipation requirements can be reduced. This component maintains the critical voltage parameters but operates at 1.45A peak pulse current and 150W peak pulse power, representing a 70% reduction in current handling capacity compared to the SA64ALF. Selection of the 1N8172 is appropriate only for applications with lower transient energy requirements.

Frequently Asked Questions (FAQ)

Q: Can the SA64A directly replace the SA64ALF in existing designs?

A: Yes. The SA64A maintains identical voltage specifications (64V standoff, 103V clamping) and equivalent peak pulse current (5A versus 4.9A). Both components are through-hole axial devices with compatible DO-204AC (DO-15) packaging. The SA64A offers improved product status and compliance certifications.

Q: What are the limitations of using the 1N8172 as a substitute?

A: The 1N8172 meets the core voltage requirements but operates at significantly reduced peak pulse current (1.45A) and power dissipation (150W). This component is suitable only for applications where transient energy levels are lower than the original design specification. Verify that your circuit's peak pulse current and power requirements do not exceed 1.45A and 150W respectively.

Q: Are there packaging differences between these substitutes?

A: The SA64A is supplied in Tape & Reel (TR) format, while the SA64ALF and 1N8172 are available in bulk packaging. Both the SA64A and SA64ALF use DO-204AC (DO-15) axial packaging. The 1N8172 uses standard axial packaging. All three components are through-hole mounted and mechanically compatible.

Q: Does the extended operating temperature range of the SA64A affect circuit performance?

A: The SA64A extends the upper operating temperature limit from 150°C to 175°C. This provides additional thermal margin in high-temperature environments but does not alter the electrical performance within the original SA64ALF operating range (-55°C to 150°C).

Q: What compliance certifications should I consider when selecting a substitute?

A: The SA64A is RoHS3 compliant, while both the SA64ALF and 1N8172 are RoHS non-compliant. All three components are REACH Unaffected and classified under ECCN EAR99. Regulatory requirements for your application will determine whether RoHS compliance is mandatory.