SA28HE3/73 Equivalent & Substitute Parts

Part Overview

The SA28HE3/73 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, part of the TransZorb® series. This component is designed for transient voltage protection in through-hole applications with a 28V reverse standoff voltage and 50.1V maximum clamping voltage. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

SA28HE3/73

Vishay General Semiconductor - Diodes DivisionIn Stock: 1049SA28HE3/73 Datasheet

Current PartRFQ

SA28AHE3/73

Vishay General Semiconductor - Diodes DivisionIn Stock: 863SA28AHE3/73 Datasheet

DirectRFQ

LCE28A

Littelfuse Inc.In Stock: 2122LCE28A Datasheet

MFR RecommendedRFQ

SA28A

Fairchild SemiconductorIn Stock: 6156SA28A Datasheet

MFR RecommendedRFQ

SA28A-B

Littelfuse Inc.In Stock: 1217SA28A-B Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SA28HE3/73 is determined by the following critical parameters:

• Voltage Rating: Reverse standoff voltage of 28V and breakdown voltage minimum of 31.1V must be maintained
• Package Compatibility: DO-204AC (DO-15) axial through-hole package for direct mechanical and electrical fit
• Thermal Performance: Operating temperature range of -55°C to 175°C
• Compliance: ROHS3 compliance and automotive-grade qualification (AEC-Q101)

Substitute parts are grouped into two categories:

Direct Package Equivalents (DO-204AC / DO-15): SA28AHE3/73, SA28A, and SA28A-B maintain identical package geometry and can be used as direct replacements in existing PCB layouts.

Functional Equivalent with Package Variation (DO-201 / DO-27): LCE28A from Littelfuse Inc. provides equivalent voltage protection with enhanced current handling capability but requires mechanical accommodation for the larger DO-201 package footprint.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Package)

SA28AHE3/73 is the primary recommended substitute. It maintains the DO-204AC (DO-15) package, identical voltage ratings, and active product status from Vishay. This part provides the most straightforward design continuity with minimal PCB modification.

SA28A-B from Littelfuse Inc. is an alternative direct replacement with active product status. It maintains all critical electrical parameters and package compatibility while offering improved long-term availability through an active manufacturer.

For Enhanced Performance with Package Accommodation

LCE28A from Littelfuse Inc. is suitable when circuit design permits mechanical accommodation of the larger DO-201 (DO-27) package. This part offers significantly higher peak pulse current (33A) and power dissipation (1500W) compared to the original 10A / 500W specification, providing enhanced transient protection margin. Active product status ensures long-term supply continuity.

All recommended substitutes maintain ROHS3 compliance and automotive-grade qualification (AEC-Q101), ensuring regulatory and quality consistency with the original SA28HE3/73 specification.

Frequently Asked Questions (FAQ)

Q: Can SA28AHE3/73 be used as a direct drop-in replacement for SA28HE3/73?

A: Yes. SA28AHE3/73 maintains identical package geometry (DO-204AC / DO-15), reverse standoff voltage (28V), breakdown voltage (31.1V), and operating temperature range (-55°C to 175°C). The clamping voltage is slightly lower (45.4V vs. 50.1V), which is acceptable for most protection applications. No PCB modifications are required.

Q: What is the difference between SA28A and SA28A-B?

A: Both parts share identical electrical specifications (28V standoff, 31.1V breakdown, 45.4V clamping, 11.2A peak pulse). The primary difference is manufacturer: SA28A is from Fairchild Semiconductor (obsolete status), while SA28A-B is from Littelfuse Inc. (active status). SA28A-B is preferred for new designs due to active product status and supply availability.

Q: Why does LCE28A have higher current and power ratings?

A: LCE28A is manufactured in the larger DO-201 (DO-27) package, which provides greater thermal mass and current-handling capability. The 33A peak pulse current and 1500W power dissipation represent the physical capabilities of this package size. Voltage protection characteristics (28V standoff, 31.1V breakdown, 45.5V clamping) remain equivalent to the original part.

Q: Can LCE28A be used in the same PCB footprint as SA28HE3/73?

A: No. LCE28A uses the DO-201 (DO-27) package, which has different lead spacing and body dimensions compared to the DO-204AC (DO-15) package. PCB layout modification is required. Use LCE28A only when circuit design permits mechanical accommodation of the larger package.

Q: Are all substitute parts automotive-qualified?

A: SA28AHE3/73, SA28A, SA28A-B, and LCE28A all carry AEC-Q101 automotive qualification and ROHS3 compliance, matching the original SA28HE3/73 specification.

Q: What is the clamping voltage difference between SA28HE3/73 and its substitutes?

A: SA28HE3/73 specifies 50.1V maximum clamping voltage. SA28AHE3/73, SA28A, and SA28A-B specify 45.4V clamping voltage. LCE28A specifies 45.5V clamping voltage. The lower clamping voltage in substitutes is within acceptable protection margins for 28V standoff applications and does not compromise transient suppression effectiveness.