SA20-B Transient Voltage Suppressor (TVS) Equivalent & Substitute Parts

Part Overview

The SA20-B is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for telecom applications. This through-hole component features a 20V reverse standoff voltage with a 32.4V maximum clamping voltage and 15.7A peak pulse current capability in a DO-204AC (DO-15) axial package format.

The SA20-B is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for systems utilizing this component.

Substiute Parts

SA20-B

Littelfuse Inc.In Stock: 803SA20-B Datasheet

Current PartRFQ

SA20A

Fairchild SemiconductorIn Stock: 300483SA20A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA20-B is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Voltage - Reverse Standoff (Typ): 20V
• Voltage - Breakdown (Min): 22.2V
• Voltage - Clamping (Max) @ Ipp: 32.4V
• Current - Peak Pulse (10/1000µs): 15.7A
• Power - Peak Pulse: 500W
• Unidirectional Channels: 1
• Type: Zener

Mechanical Equivalence Criteria:

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

The SA20A, manufactured by Fairchild Semiconductor, meets all specified electrical and mechanical parameters for direct substitution with the SA20-B. Both components are classified as obsolete and share identical voltage ratings, current handling, power dissipation, and package configuration.

Parameter Comparison

*Note: SA20A operating temperature minimum is -55°C versus SA20-B at -65°C. Applications requiring operation below -55°C require verification against system specifications.

Engineering Selection Recommendations

SA20A as Direct Substitute:

The SA20A from Fairchild Semiconductor is a direct electrical and mechanical equivalent to the SA20-B. Both components are obsolete products with identical voltage ratings, current handling capacity, power dissipation, and DO-204AC through-hole package configuration.

Compliance Considerations:

Both the SA20-B and SA20A are RoHS compliant, meeting environmental regulatory requirements. The SA20A carries ROHS3 certification, indicating compliance with the most current RoHS standards.

Temperature Range Consideration:

The SA20A specifies an operating temperature range of -55°C to 175°C, compared to the SA20-B range of -65°C to 175°C. For applications requiring operation at temperatures below -55°C, the SA20A may not be suitable. System design specifications must be reviewed to determine if the lower temperature limit of the SA20A is acceptable for the intended application.

Availability:

The SA20A is available in significantly higher inventory quantities (300,400 pieces) compared to the SA20-B (709 pieces), making it the preferred substitute for ongoing production requirements.

Frequently Asked Questions (FAQ)

Q: Can the SA20A replace the SA20-B in all applications?

A: The SA20A is electrically and mechanically equivalent to the SA20-B across all specified parameters. However, applications requiring operation below -55°C must be evaluated against system temperature specifications, as the SA20A minimum operating temperature is -55°C versus the SA20-B at -65°C.

Q: Are the package configurations identical?

A: Yes. Both the SA20-B and SA20A use the DO-204AC (DO-15) axial through-hole package. They are mechanically interchangeable in PCB designs and through-hole mounting applications.

Q: What is the difference in RoHS compliance between the two parts?

A: Both parts are RoHS compliant. The SA20A carries ROHS3 certification, representing the current RoHS standard. The SA20-B is listed as RoHS Compliant. Both meet environmental regulatory requirements for electronic component manufacturing and use.

Q: Why is the SA20A preferred despite the narrower temperature range?

A: The SA20A is preferred for supply chain continuity due to significantly higher inventory availability (300,400 pieces versus 709 pieces). For applications operating within the -55°C to 175°C range, the SA20A provides equivalent performance with assured supply.

Q: Are there any electrical performance differences between SA20-B and SA20A?

A: No. Both components share identical electrical specifications: 20V reverse standoff voltage, 22.2V minimum breakdown voltage, 32.4V maximum clamping voltage, 15.7A peak pulse current, and 500W peak pulse power rating.

Q: What applications are these components suitable for?

A: The SA20-B is specified for telecom applications. The SA20A is designated for general purpose applications. Both are unidirectional Zener-type TVS diodes suitable for transient voltage suppression in electronic circuits.