SA8.5-B Equivalent & Substitute Parts

Part Overview

The SA8.5-B is a Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for telecom applications. This unidirectional zener diode operates with an 8.5V reverse standoff voltage and provides 14.4V clamping at peak pulse current. The device is packaged in a DO-204AC (DO-15) through-hole axial configuration and is rated for 500W peak pulse power dissipation across an operating temperature range of -65°C to 175°C.

The SA8.5-B carries an obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this TVS diode specification.

Substiute Parts

SA8.5-B

Littelfuse Inc.In Stock: 1107SA8.5-B Datasheet

Current PartRFQ

SA8.5A

Taiwan Semiconductor CorporationIn Stock: 8461SA8.5A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA8.5-B is determined by strict equivalence across the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Voltage - Reverse Standoff (Typ): 8.5V
• Voltage - Breakdown (Min): 9.44V
• Voltage - Clamping (Max) @ Ipp: 14.4V
• Current - Peak Pulse (10/1000µs): ≥35.4A
• Power - Peak Pulse: 500W
• Type: Zener, Unidirectional

Mechanical Equivalence Criteria:

• Package / Case: DO-204AC (DO-15), Axial
• Mounting Type: Through Hole
• Unidirectional Channels: 1

The SA8.5A, manufactured by Taiwan Semiconductor Corporation, meets all electrical and mechanical substitution criteria. This part maintains identical voltage specifications, equivalent peak pulse current capability (36A), and identical package configuration. Both devices are RoHS compliant and operate across overlapping temperature ranges suitable for the intended application.

Parameter Comparison

Engineering Selection Recommendations

SA8.5A Selection Basis:

The SA8.5A is a direct functional equivalent to the SA8.5-B and is suitable for applications requiring replacement of the obsolete Littelfuse part. The SA8.5A maintains identical electrical performance across all critical voltage and power parameters. The peak pulse current specification of 36A exceeds the SA8.5-B requirement of 35.4A, providing equivalent or superior transient suppression capability.

The SA8.5A carries an active product status, ensuring ongoing availability and supply chain support. The device is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The operating temperature range of -55°C to 175°C encompasses the upper operating limit of the SA8.5-B and is suitable for telecom and general-purpose applications.

Both devices share identical DO-204AC (DO-15) axial through-hole packaging, enabling direct mechanical substitution without circuit board redesign or layout modification.

Frequently Asked Questions (FAQ)

Q: Can the SA8.5A directly replace the SA8.5-B in existing designs?

A: Yes. The SA8.5A is electrically and mechanically equivalent to the SA8.5-B. Both devices feature identical voltage specifications (8.5V standoff, 14.4V clamping), equivalent peak pulse current ratings, and identical DO-204AC through-hole axial packaging. Direct substitution is supported without circuit modification.

Q: What is the difference in peak pulse current between these parts?

A: The SA8.5-B is rated for 35.4A peak pulse current, while the SA8.5A is rated for 36A. This 0.6A difference represents a marginal increase in current handling capability and does not affect substitution compatibility. The SA8.5A meets or exceeds the SA8.5-B specification.

Q: Are there packaging differences between the SA8.5-B and SA8.5A?

A: No. Both parts use identical DO-204AC (DO-15) axial through-hole packaging. The SA8.5-B is supplied in standard packaging, while the SA8.5A is available in Tape & Reel (TR) format. The physical component dimensions and pin configuration are identical, supporting direct board-level substitution.

Q: What is the operating temperature difference, and does it affect substitution?

A: The SA8.5-B operates from -65°C to 175°C, while the SA8.5A operates from -55°C to 175°C. The SA8.5A has a narrower lower temperature limit by 10°C. For applications operating above -55°C, this difference is not relevant. For applications requiring operation below -55°C, the SA8.5-B specification must be maintained.

Q: Why is the SA8.5-B listed as obsolete?

A: The SA8.5-B carries an obsolete product status from Littelfuse Inc. The SA8.5A, manufactured by Taiwan Semiconductor Corporation, is an active product with ongoing production and supply availability, making it the recommended substitute for new designs and ongoing production support.

Q: Are both parts RoHS compliant?

A: Yes. The SA8.5-B is RoHS compliant. The SA8.5A is ROHS3 compliant, representing a more current environmental compliance standard. Both parts meet RoHS requirements for hazardous substance restrictions.