SA85C-B Equivalent & Substitute Parts

Part Overview

The SA85C-B is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for telecom applications. This through-hole component features an 85V reverse standoff voltage with a 137V maximum clamping voltage and 3.7A peak pulse current capability. The part is classified as obsolete, necessitating identification of active equivalent alternatives to maintain design continuity and ensure ongoing component availability for new production and field replacements.

Substiute Parts

SA85C-B

Littelfuse Inc.In Stock: 1150SA85C-B Datasheet

Current PartRFQ

SA85CA

Taiwan Semiconductor CorporationIn Stock: 1197SA85CA Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA85C-B is determined by strict equivalence across the following critical parameters:

Voltage Parameters: Reverse standoff voltage of 85V, minimum breakdown voltage of 94.4V, and maximum clamping voltage of 137V must remain constant across all substitute parts.

Current and Power Ratings: Peak pulse current and peak pulse power specifications establish the transient suppression capability. Substitute parts must meet or exceed these ratings.

Package and Mounting: The DO-204AC (DO-15) axial through-hole package is a fixed requirement for mechanical and electrical compatibility within existing circuit designs.

Electrical Type: Zener diode topology with single bidirectional channel configuration must be maintained.

Temperature Range: Operating temperature specifications must support the intended application environment.

The SA85CA qualifies as a direct substitute based on matching all critical voltage, current, power, package, and electrical type parameters.

Parameter Comparison

Engineering Selection Recommendations

The SA85CA is a qualified substitute for the obsolete SA85C-B based on electrical and mechanical parameter equivalence. Both parts maintain identical voltage specifications (85V standoff, 94.4V breakdown, 137V clamping), power ratings (500W peak pulse), and package configuration (DO-204AC through-hole).

The SA85CA demonstrates superior peak pulse current capability at 3.8A compared to the SA85C-B at 3.7A, providing enhanced transient suppression margin. Both parts maintain RoHS compliance and unlimited moisture sensitivity rating (MSL 1).

The primary consideration is the operating temperature range. The SA85C-B supports -65°C to 175°C, while the SA85CA operates from -55°C to 175°C. Applications requiring operation below -55°C ambient or junction temperature must evaluate this specification difference against actual system requirements.

The SA85CA is actively manufactured and stocked, ensuring long-term component availability for production and field service applications.

Frequently Asked Questions (FAQ)

Q: Can the SA85CA directly replace the SA85C-B in existing designs?

A: Yes, the SA85CA provides direct electrical and mechanical substitution. Both parts share identical voltage ratings (85V standoff, 137V clamping), power specifications (500W), and DO-204AC through-hole packaging. The SA85CA actually exceeds the original specification with 3.8A peak pulse current versus 3.7A.

Q: What is the significance of the different operating temperature ranges?

A: The SA85C-B operates from -65°C to 175°C junction temperature, while the SA85CA operates from -55°C to 175°C. If your application requires operation below -55°C, the SA85CA may not be suitable. For standard commercial and industrial temperature ranges, this difference is typically not a limiting factor.

Q: Are both parts RoHS compliant?

A: Yes. The SA85C-B is RoHS Compliant, and the SA85CA is ROHS3 Compliant. Both meet current environmental and hazardous substance restrictions.

Q: What is the packaging difference between these parts?

A: The SA85C-B is supplied in standard packaging, while the SA85CA is supplied in Tape & Reel (TR) format. Both use the identical DO-204AC (DO-15) axial through-hole component package. Tape & Reel packaging is standard for automated assembly processes.

Q: Why is the SA85C-B listed as obsolete?

A: The SA85C-B is an older Littelfuse product that has been discontinued. The SA85CA from Taiwan Semiconductor Corporation provides equivalent functionality and is actively manufactured, making it the recommended alternative for new designs and ongoing production.

Q: Are there any compliance differences between the two parts?

A: Both parts are RoHS compliant and carry MSL 1 (Unlimited) moisture sensitivity rating. The SA85CA includes REACH Unaffected status. Both share the same ECCN (EAR99) and HTSUS (8541.10.0080) classifications.