SA28A-B Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA28A-B is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. This through-hole component operates across a temperature range of -55°C to 175°C and is housed in a DO-204AC (DO-15) axial package. The SA28A-B maintains active product status with 1112 units currently in stock and full ROHS3 compliance.

Substitute parts become necessary when the primary SA28A-B component reaches end-of-life status, experiences supply chain constraints, or when alternative sourcing is required to meet project timelines and inventory requirements.

Substiute Parts

SA28A-B

Littelfuse Inc.In Stock: 1217SA28A-B Datasheet

Current PartRFQ

SA28A

Fairchild SemiconductorIn Stock: 6156SA28A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SA28A-B is determined by strict electrical and mechanical parameter matching:

Critical Matching Parameters:

• Voltage - Reverse Standoff (Typ): 28V
• Voltage - Breakdown (Min): 31.1V
• Voltage - Clamping (Max) @ Ipp: 45.4V
• Current - Peak Pulse (10/1000µs): 11.2A
• Power - Peak Pulse: 500W
• Package / Case: DO-204AC (DO-15), Axial
• Mounting Type: Through Hole
• Operating Temperature Range: -55°C to 175°C

The SA28A (Fairchild Semiconductor) qualifies as a direct substitute based on identical electrical specifications and mechanical compatibility. Both components share the same voltage ratings, peak pulse current capacity, power dissipation capability, and physical package configuration.

Parameter Comparison

Engineering Selection Recommendations

SA28A-B (Littelfuse Inc.) - Primary Selection

• Active product status ensures long-term availability and manufacturer support
• Current inventory of 1112 units supports immediate procurement
• ROHS3 compliance and REACH unaffected status meet environmental regulatory requirements
• Recommended for new designs and applications requiring sustained component supply

SA28A (Fairchild Semiconductor) - Substitute Selection

• Obsolete product status indicates limited future availability
• Current inventory of 6100 units provides near-term sourcing capability
• Identical electrical and mechanical specifications ensure direct circuit compatibility
• Suitable for legacy system maintenance, repair, and retrofit applications where component replacement is necessary
• ROHS3 compliance maintains environmental regulatory alignment

Selection between these components should prioritize the SA28A-B for new applications due to active product status. The SA28A serves as a viable alternative when SA28A-B supply is constrained or when supporting existing systems already utilizing Fairchild components.

Frequently Asked Questions (FAQ)

Q: Can SA28A (Fairchild) be used as a direct replacement for SA28A-B (Littelfuse)? A: Yes. Both components share identical voltage ratings (28V standoff, 31.1V breakdown minimum, 45.4V clamping maximum), peak pulse current (11.2A), power dissipation (500W), operating temperature range (-55°C to 175°C), and DO-204AC axial package configuration. Electrical and mechanical compatibility is complete.

Q: What is the primary difference between these two parts? A: The SA28A-B is an active product from Littelfuse with current manufacturing support. The SA28A from Fairchild is obsolete, indicating discontinued production. Both maintain identical functional specifications and package form factors.

Q: Are there any compliance or certification differences? A: Both components are ROHS3 compliant. The SA28A-B is REACH unaffected. Both carry EAR99 export classification and identical HTSUS codes (8541.10.0080). No compliance barriers exist for substitution.

Q: Can these parts be used interchangeably in PCB designs? A: Yes. The identical DO-204AC (DO-15) axial package and through-hole mounting type ensure mechanical and electrical interchangeability on printed circuit boards. No PCB layout modifications are required.

Q: Which part should be specified for new product designs? A: Specify SA28A-B (Littelfuse) for new designs. Active product status ensures manufacturer support, long-term availability, and compliance with current supply chain standards.

Q: What applications are these components suitable for? A: Both components are rated for general-purpose transient voltage suppression applications requiring 28V standoff protection with 11.2A peak pulse current handling capability.