SA12-B Equivalent & Substitute Parts

Part Overview

The SA12-B is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for telecom applications. This component features a 12V reverse standoff voltage with a 19.9V maximum clamping voltage and 25.6A peak pulse current capability. The SA12-B is classified as obsolete, necessitating identification of equivalent substitute parts for ongoing design support and procurement continuity. Substitute parts must maintain electrical performance within the specified voltage and current parameters while accommodating packaging and compliance requirements.

Substiute Parts

SA12-B

Littelfuse Inc.In Stock: 1051SA12-B Datasheet

Current PartRFQ

SA12A

Fairchild SemiconductorIn Stock: 2436SA12A Datasheet

DirectRFQ

SA12A-B

Littelfuse Inc.In Stock: 1707SA12A-B Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SA12-B are qualified based on the following electrical and mechanical parameters:

Critical Matching Parameters:

• Voltage - Reverse Standoff: 12V
• Voltage - Clamping (Max) @ Ipp: 19.9V
• Voltage - Breakdown (Min): 13.3V
• Current - Peak Pulse (10/1000µs): minimum 25.1A
• Power - Peak Pulse: 500W
• Package / Case: DO-204AC or DO-15 (Axial)
• Mounting Type: Through Hole
• Type: Zener
• Unidirectional Channels: 1

The SA12A and SA12A-B meet these electrical specifications. The SA12A-B is manufactured by Littelfuse Inc. (same manufacturer as the main part) and maintains active product status with enhanced compliance certifications. The SA12A, manufactured by Fairchild Semiconductor, provides equivalent electrical performance with identical voltage parameters and comparable peak pulse current (25.1A versus 25.6A).

Parameter Comparison

Engineering Selection Recommendations

SA12A-B (Littelfuse Inc.): This substitute is the preferred selection for new designs and procurement. The SA12A-B maintains active product status, ensuring long-term availability and manufacturing support. It is manufactured by Littelfuse Inc., the original manufacturer of the SA12-B, providing design continuity. The part carries ROHS3 compliance and REACH Unaffected status, meeting current regulatory requirements. Electrical specifications are identical to the SA12-B, with peak pulse current matching at 25.6A. The operating temperature range (-55°C to 175°C) covers the majority of applications, with a 10°C reduction at the lower bound compared to the SA12-B.

SA12A (Fairchild Semiconductor): This substitute provides equivalent electrical performance with all critical voltage parameters matching the SA12-B. Peak pulse current is specified at 25.1A, representing a 0.5A reduction from the SA12-B. The SA12A is classified as obsolete, limiting its suitability for new procurement. Operating temperature range is not specified in available documentation. ROHS3 compliance is confirmed. This part is suitable only when SA12A-B availability is constrained and the 0.5A current reduction is acceptable for the application.

Frequently Asked Questions (FAQ)

Q: Can SA12A and SA12A-B be used interchangeably with SA12-B?

A: Both SA12A and SA12A-B meet the critical electrical specifications of the SA12-B: 12V reverse standoff voltage, 19.9V clamping voltage, and 500W peak pulse power. Both are packaged in DO-15 (DO-204AC) through-hole format. The SA12A-B is the preferred substitute due to active product status and identical peak pulse current (25.6A). The SA12A is functionally equivalent with a 0.5A reduction in peak pulse current.

Q: What is the difference between SA12A and SA12A-B?

A: Both parts share identical electrical specifications. The primary differences are: (1) Manufacturer—SA12A is Fairchild Semiconductor; SA12A-B is Littelfuse Inc.; (2) Product Status—SA12A is obsolete; SA12A-B is active; (3) Operating Temperature—SA12A-B specifies -55°C to 175°C; SA12A does not specify this range; (4) Peak Pulse Current—SA12A-B matches the SA12-B at 25.6A; SA12A is rated at 25.1A.

Q: Are there packaging differences between these parts?

A: All three parts use through-hole axial packaging. The SA12-B and SA12A-B are specified as DO-204AC (DO-15). The SA12A is specified as DO-15. These designations refer to the same physical package format and are mechanically compatible for PCB mounting.

Q: Which substitute should be selected for new designs?

A: SA12A-B is the recommended selection for new designs. It is the only active product among the three parts, ensuring manufacturing continuity and long-term availability. It is manufactured by Littelfuse Inc., the original SA12-B manufacturer, and carries current compliance certifications (ROHS3, REACH Unaffected).

Q: What compliance certifications apply to these parts?

A: SA12-B carries RoHS Compliance certification. SA12A and SA12A-B both carry ROHS3 Compliance certification. SA12A-B additionally carries REACH Unaffected status. All three parts are classified under ECCN EAR99 and HTSUS 8541.10.0080.

Q: Is the 0.5A difference in peak pulse current between SA12A and SA12-B significant?

A: The SA12A is rated at 25.1A peak pulse current compared to 25.6A for the SA12-B. This 0.5A reduction (approximately 2%) remains within typical application tolerances for TVS diode selection. However, applications with peak pulse current requirements exceeding 25.1A must use SA12A-B or the original SA12-B.

Q: What is the moisture sensitivity level for these parts?

A: SA12-B and SA12A-B both specify MSL 1 (Unlimited), indicating no moisture sensitivity restrictions for storage and handling. SA12A does not specify MSL in available documentation.