SA8.5 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SA8.5 is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection applications. The device features an 8.5V reverse standoff voltage with a 15.12V maximum clamping voltage and 35.4A peak pulse current capability in a through-hole DO-204AC (DO-15) axial package.

The SA8.5 is classified as obsolete. Identifying equivalent 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

SA8.5

Littelfuse Inc.In Stock: 985SA8.5 Datasheet

Current PartRFQ

SA8.5A

Taiwan Semiconductor CorporationIn Stock: 8461SA8.5A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SA8.5 is determined by the following critical electrical and mechanical parameters:

• Voltage - Reverse Standoff: Must match 8.5V (±tolerance)
• Voltage - Clamping (Max) @ Ipp: Must be within acceptable range (14.4V to 15.12V)
• Current - Peak Pulse (10/1000µs): Must meet or exceed 35.4A
• Power - Peak Pulse: Must support 500W minimum
• Package / Case: Must be DO-204AC (DO-15) axial through-hole
• Operating Temperature Range: Must cover -55°C to 175°C (TJ)
• Type: Zener unidirectional TVS diode
• Unidirectional Channels: 1

The SA8.5A from Taiwan Semiconductor Corporation qualifies as a direct substitute based on matching all critical parameters within acceptable engineering tolerances.

Parameter Comparison

Engineering Selection Recommendations

The SA8.5A from Taiwan Semiconductor Corporation is a qualified substitute for the obsolete SA8.5 from Littelfuse Inc. based on the following criteria:

All critical electrical parameters match or exceed the original specification. The reverse standoff voltage, peak pulse current, power dissipation, and operating temperature range are identical or compatible. The clamping voltage of the SA8.5A (14.4V) is lower than the original (15.12V), which provides improved transient suppression performance within acceptable design margins.

Both parts are ROHS3 compliant and carry identical moisture sensitivity levels (MSL 1 - Unlimited), ensuring regulatory and environmental compatibility.

The SA8.5A is currently in active production status with substantial inventory availability (8400 pcs), whereas the SA8.5 is obsolete. The SA8.5A is supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

The identical DO-204AC (DO-15) axial through-hole package ensures direct mechanical and electrical compatibility without PCB redesign or rework.

Frequently Asked Questions (FAQ)

Q: Can the SA8.5A be used as a direct replacement for the SA8.5 without circuit modification?

A: Yes. The SA8.5A meets all critical electrical and mechanical parameters. The identical package, mounting type, and operating temperature range enable direct substitution without PCB layout changes or design modifications.

Q: What is the significance of the clamping voltage difference (15.12V vs. 14.4V)?

A: The SA8.5A exhibits a lower maximum clamping voltage, which indicates faster transient suppression and potentially lower voltage stress on protected circuitry. This represents an improvement over the original specification and remains within acceptable design tolerances for general-purpose overvoltage protection applications.

Q: Are there compliance or certification differences between the two parts?

A: Both parts are ROHS3 compliant with identical moisture sensitivity levels (MSL 1). No compliance or certification gaps exist between the SA8.5 and SA8.5A.

Q: What packaging options are available for the SA8.5A?

A: The SA8.5A is supplied in Tape & Reel (TR) packaging, optimized for automated pick-and-place assembly. The original SA8.5 packaging information was not specified in available data.

Q: Why is the SA8.5 classified as obsolete?

A: The SA8.5 has been discontinued by Littelfuse Inc. The SA8.5A represents the active production equivalent within the SA series, ensuring continued availability and supply chain support.

Q: Are there any thermal or performance considerations when substituting the SA8.5A?

A: Both parts share identical operating temperature ranges (-55 to 175°C TJ) and peak pulse power ratings (500W). No thermal performance degradation or derating is required when using the SA8.5A as a substitute.