SA24-B Equivalent & Substitute Parts

Part Overview

The SA24-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 24V reverse standoff voltage with a 38.9V maximum clamping voltage and 13.1A peak pulse current capability in a through-hole DO-204AC (DO-15) axial package.

The SA24-B is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production and field service requirements for systems utilizing this component.

Substiute Parts

SA24-B

Littelfuse Inc.In Stock: 1149SA24-B Datasheet

Current PartRFQ

SA24A

Fairchild SemiconductorIn Stock: 1579SA24A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA24-B is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Voltage - Reverse Standoff (Typ): 24V
• Voltage - Breakdown (Min): 26.7V
• Voltage - Clamping (Max) @ Ipp: 38.9V
• Current - Peak Pulse (10/1000µs): 13.1A
• Power - Peak Pulse: 500W
• Type: Zener, Unidirectional (1 channel)

Mechanical Equivalence Criteria:

• Package / Case: DO-204AC (DO-15), Axial through-hole configuration
• Mounting Type: Through Hole

The SA24A, manufactured by Fairchild Semiconductor, meets all specified electrical and mechanical parameters for direct substitution. Both components are classified as obsolete and share identical voltage ratings, current handling, power dissipation, and physical packaging specifications.

Parameter Comparison

*Operating temperature lower limit differs: SA24-B operates from -65°C while SA24A operates from -55°C. Both reach 175°C maximum.

Engineering Selection Recommendations

SA24A as Direct Substitute:

The SA24A is electrically and mechanically equivalent to the SA24-B across all critical transient voltage suppression parameters. Both components are classified as obsolete products and share identical voltage ratings (24V standoff, 26.7V breakdown minimum, 38.9V clamping maximum), current handling (13.1A peak pulse), and power dissipation (500W peak pulse). Both are packaged in DO-204AC (DO-15) axial through-hole configuration.

Compliance Considerations:

The SA24-B carries RoHS Compliant certification, while the SA24A carries ROHS3 Compliant certification. Both meet current environmental and hazardous substance restriction standards. The SA24A represents a more recent compliance designation.

Temperature Range Consideration:

The SA24-B specifies an operating temperature range of -65°C to 175°C, while the SA24A specifies -55°C to 175°C. Applications requiring operation below -55°C must retain the SA24-B. For applications within the -55°C to 175°C range, the SA24A is suitable.

Inventory and Availability:

SA24-B: 1071 pieces in stock (Littelfuse) SA24A: 1530 pieces in stock (Fairchild)

Frequently Asked Questions (FAQ)

Q: Can the SA24A replace the SA24-B in all applications?

A: The SA24A is electrically and mechanically equivalent for applications operating within the -55°C to 175°C temperature range. Applications requiring operation below -55°C must use the SA24-B due to its extended lower temperature limit of -65°C.

Q: Are the physical packages identical?

A: Yes. Both the SA24-B and SA24A use the DO-204AC (DO-15) axial through-hole package. They are mechanically interchangeable in PCB layouts and through-hole mounting applications.

Q: What are the key electrical parameters that define substitution?

A: Substitution is determined by matching: Reverse Standoff Voltage (24V), Breakdown Voltage minimum (26.7V), Clamping Voltage maximum (38.9V), Peak Pulse Current (13.1A), and Peak Pulse Power (500W). The SA24A matches all these parameters.

Q: Do both parts have the same RoHS compliance status?

A: Both parts are RoHS compliant. The SA24-B carries RoHS Compliant designation, while the SA24A carries ROHS3 Compliant designation. Both meet current environmental standards.

Q: Are there any differences in applications between these parts?

A: The SA24-B is specified for telecom applications, while the SA24A is specified for general purpose applications. Both are suitable for transient voltage suppression in their respective application domains.

Q: What is the significance of both parts being obsolete?

A: Both components are classified as obsolete, indicating they are no longer in active production. Existing inventory from both manufacturers remains available. Long-term availability should be confirmed with suppliers for future production planning.