SA28AG Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA28AG is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in through-hole axial configurations. This component operates with a 28V reverse standoff voltage and provides 45.4V maximum clamping voltage at peak pulse current. The SA28AG is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and component procurement.

Substiute Parts

SA28AG

onsemiIn Stock: 815SA28AG Datasheet

Current PartRFQ

SA28A

Fairchild SemiconductorIn Stock: 6156SA28A Datasheet

DirectRFQ

1N8163

Microchip TechnologyIn Stock: 7801N8163 Datasheet

SimilarRFQ

5KP28A-G

Comchip TechnologyIn Stock: 7265KP28A-G Datasheet

SimilarRFQ

SA28A-B

Littelfuse Inc.In Stock: 1217SA28A-B Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA28AG is determined by strict equivalence across the following critical electrical and mechanical parameters:

• Voltage Rating: Reverse standoff voltage of 28V ± tolerance, breakdown voltage minimum of 31.1V, and clamping voltage maximum of 45.4V
• Current Handling: Peak pulse current capability at 10/1000µs pulse duration
• Power Dissipation: Peak pulse power rating
• Package Compatibility: Through-hole axial or DO-204AC (DO-15) configurations
• Temperature Range: Operating temperature specifications

Substitute parts are grouped into two categories:

Direct Equivalents maintain identical or near-identical electrical specifications and package form factors, enabling direct board-level replacement without circuit modification.

Functional Equivalents meet the core voltage and current requirements but may differ in peak pulse current capacity or package configuration, requiring application-level verification of suitability.

Parameter Comparison

Engineering Selection Recommendations

SA28A-B (Littelfuse Inc.) is the primary recommended substitute. This part maintains identical voltage specifications (28V standoff, 31.1V breakdown, 45.4V clamping) and equivalent peak pulse current (11.2A vs. 11A). The SA28A-B is currently active in production, ROHS3 compliant, and rated for extended operating temperature (-55°C to 175°C). The DO-204AC (DO-15) package provides direct mechanical compatibility with the SA28AG axial form factor.

SA28A (Fairchild Semiconductor) provides equivalent electrical performance with 11.2A peak pulse current and identical voltage ratings. However, this part is obsolete, limiting long-term procurement viability. Use only when SA28A-B availability is constrained.

5KP28A-G (Comchip Technology) is suitable for applications requiring higher transient energy absorption. This part maintains the 28V voltage rating and 45.4V clamping voltage but provides significantly higher peak pulse current (110.13A) and power dissipation (5000W). The R-6 package differs from the standard axial form factor. Selection of this part requires verification that the larger package footprint accommodates board layout constraints.

1N8163 (Microchip Technology) is not recommended as a direct substitute. Although it maintains the 28V voltage rating, the peak pulse current (3.28A) and power dissipation (150W) are substantially lower than the SA28AG specification. This part is suitable only for applications with reduced transient current requirements. Additionally, this part is RoHS non-compliant.

Frequently Asked Questions (FAQ)

Q: Can SA28A-B be used as a direct replacement for SA28AG without circuit modification?

A: Yes. The SA28A-B maintains identical voltage specifications and equivalent peak pulse current within the same package family (DO-204AC/DO-15 axial). No circuit modification is required for direct substitution.

Q: What is the difference between the SA28AG and 5KP28A-G?

A: Both parts share the same 28V voltage rating and 45.4V clamping voltage. The primary difference is peak pulse current capacity: SA28AG handles 11A while 5KP28A-G handles 110.13A. The 5KP28A-G is designed for higher-energy transient suppression applications. The R-6 package of the 5KP28A-G is physically larger than the standard axial package, requiring board layout verification before substitution.

Q: Why is 1N8163 not recommended as a substitute?

A: The 1N8163 has significantly reduced peak pulse current (3.28A) and power dissipation (150W) compared to the SA28AG (11A, 500W). This part is suitable only for applications with lower transient current requirements. Additionally, 1N8163 is RoHS non-compliant, which may conflict with procurement or regulatory requirements.

Q: Are there temperature range differences between substitute parts?

A: Yes. The SA28AG operates from -55°C to 150°C. SA28A-B, SA28A, and 1N8163 extend to -55°C to 175°C, providing wider temperature margin. The 5KP28A-G matches the SA28AG at -55°C to 150°C. Verify application temperature requirements before selection.

Q: What compliance certifications should I verify for substitute parts?

A: SA28A-B and 5KP28A-G are ROHS3 compliant. The 1N8163 is RoHS non-compliant. All parts listed are REACH unaffected and classified as EAR99 for export control purposes. Verify compliance requirements with your procurement and regulatory teams.

Q: Can I use 5KP28A-G in a circuit designed for SA28AG?

A: Electrical substitution is valid due to matching voltage specifications. However, the R-6 package is physically larger than the standard axial package. Verify that board layout and component spacing accommodate the larger footprint before implementation.