SA120-B Equivalent & Substitute Parts

Part Overview

The SA120-B is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for transient overvoltage protection in telecom applications. This component features a 120V reverse standoff voltage with a 193V maximum clamping voltage and 2.6A peak pulse current rating in a through-hole DO-204AC (DO-15) axial package.

The SA120-B is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production and maintenance requirements for systems utilizing this component.

Substiute Parts

SA120-B

Littelfuse Inc.In Stock: 789SA120-B Datasheet

Current PartRFQ

SA120A

Taiwan Semiconductor CorporationIn Stock: 1090SA120A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SA120-B TVS diode are identified based on strict electrical and mechanical parameter equivalence. The following criteria determine substitution eligibility:

Electrical Parameters (Must Match):

• Voltage - Reverse Standoff (Typ): 120V
• Voltage - Breakdown (Min): 133V
• Voltage - Clamping (Max) @ Ipp: 193V
• Power - Peak Pulse: 500W
• Type: Zener
• Unidirectional Channels: 1

Mechanical Parameters (Must Match):

• Package / Case: DO-204AC (DO-15)
• Mounting Type: Through Hole

Allowable Variations:

• Current - Peak Pulse (10/1000µs): ≥2.6A (higher values acceptable)
• Operating Temperature Range: May differ if minimum and maximum bounds encompass or equal the original specification
• Packaging Format: May differ (bulk, tape & reel, etc.)
• Manufacturer: Different manufacturers permitted if electrical and mechanical specifications are met

The SA120A meets all substitution criteria and is classified as an active product with improved current rating and current availability.

Parameter Comparison

Engineering Selection Recommendations

SA120A (Taiwan Semiconductor Corporation) - Primary Substitute

The SA120A is the direct equivalent substitute for the SA120-B. This part maintains identical electrical specifications across all critical parameters: reverse standoff voltage, breakdown voltage, clamping voltage, and power dissipation rating. The SA120A provides a 2.7A peak pulse current rating, which exceeds the SA120-B requirement of 2.6A, ensuring compatibility in all applications where the original part was specified.

The SA120A is classified as an active product with current manufacturing status and documented inventory availability (1073 pcs), providing reliable supply chain access compared to the obsolete SA120-B. The part carries ROHS3 compliance certification, representing enhanced environmental and regulatory adherence over the original RoHS Compliant designation.

The operating temperature range of the SA120A (-55°C to 175°C) is narrower than the SA120-B (-65°C to 175°C) at the lower bound. Applications requiring operation below -55°C require explicit verification against system requirements.

Both parts share identical mechanical specifications: DO-204AC (DO-15) axial through-hole package, enabling direct physical substitution without PCB layout modifications or mechanical redesign.

Frequently Asked Questions (FAQ)

Q: Can the SA120A directly replace the SA120-B in existing designs?

A: Yes. The SA120A meets all electrical and mechanical specifications required for SA120-B substitution. Both components feature identical reverse standoff voltage (120V), breakdown voltage (133V), clamping voltage (193V), power rating (500W), and package format (DO-204AC through-hole). The SA120A's higher peak pulse current (2.7A vs. 2.6A) provides additional margin. Direct PCB substitution is possible without layout changes.

Q: What is the difference in operating temperature range between these parts?

A: The SA120-B operates from -65°C to 175°C, while the SA120A operates from -55°C to 175°C. The SA120A has a higher minimum operating temperature by 10°C. Applications requiring operation at temperatures below -55°C must confirm compatibility with system thermal requirements before substitution.

Q: Are there packaging differences between SA120-B and SA120A?

A: Both parts use the DO-204AC (DO-15) axial through-hole package. The SA120-B is supplied in standard packaging, while the SA120A is supplied in Tape & Reel (TR) format. This difference affects handling and assembly processes but does not impact electrical performance or physical footprint. Component-level substitution is mechanically compatible.

Q: What compliance certifications apply to the SA120A?

A: The SA120A carries ROHS3 compliance certification and is REACH Unaffected. These certifications represent current regulatory standards for electronic components. The original SA120-B carries RoHS Compliant certification. The SA120A's enhanced compliance status supports modern procurement and environmental requirements.

Q: Why is the SA120-B classified as obsolete?

A: The SA120-B is no longer in active production. The SA120A serves as the active equivalent, providing identical electrical performance with improved availability and current compliance certifications. Transitioning to the SA120A ensures long-term supply chain continuity and access to documented technical support.

Q: Is the 2.7A peak pulse current of the SA120A compatible with SA120-B applications?

A: Yes. The SA120A's 2.7A peak pulse current exceeds the SA120-B specification of 2.6A. This higher rating provides additional transient suppression capability and margin in applications designed for the original 2.6A specification. No design modifications are required.