1KSMB91 Equivalent & Substitute Parts

Part Overview

The 1KSMB91 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for transient overvoltage protection in surface mount applications. This component features a 77.8V reverse standoff voltage with 125V maximum clamping voltage and 8A peak pulse current capability in a DO-214AA (SMB) package.

The 1KSMB91 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications requiring this voltage suppression specification.

Substiute Parts

1KSMB91

Littelfuse Inc.In Stock: 8871KSMB91 Datasheet

Current PartRFQ

1KSMB91A

Taiwan Semiconductor CorporationIn Stock: 94271KSMB91A Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1KSMB91 is determined by strict equivalence across the following electrical and mechanical parameters:

• Voltage Rating: Reverse standoff voltage of 77.8V, breakdown minimum of 86.5V, and maximum clamping voltage of 125V must be maintained
• Current Specification: Peak pulse current of 8A (10/1000µs pulse) is required
• Power Dissipation: Peak pulse power rating of 1000W must be supported
• Package Compatibility: DO-214AA (SMB) surface mount package is mandatory
• Device Type: Unidirectional Zener TVS diode configuration

The 1KSMB91A from Taiwan Semiconductor Corporation meets all specified electrical parameters and package requirements, qualifying it as a direct substitute for the obsolete 1KSMB91.

Parameter Comparison

Engineering Selection Recommendations

The 1KSMB91A is a qualified substitute for the obsolete 1KSMB91 based on the following criteria:

Electrical Equivalence: All critical voltage and current parameters are identical. The 1KSMB91A maintains the same 77.8V reverse standoff, 86.5V minimum breakdown, 125V maximum clamping voltage, and 8A peak pulse current specification.

Package Compatibility: Both devices utilize the DO-214AA (SMB) surface mount package, ensuring mechanical and thermal compatibility with existing PCB layouts and assembly processes.

Compliance Status: The 1KSMB91A holds ROHS3 compliance, meeting current regulatory requirements. The substitute part is classified as active product status, ensuring long-term availability and supply chain stability compared to the obsolete 1KSMB91.

Operating Temperature Range: The 1KSMB91A provides an extended operating temperature range (-55°C ~ 175°C) compared to the original part (-65°C ~ 150°C), offering improved performance margin in thermal environments.

Moisture Sensitivity: Both parts maintain MSL 1 (Unlimited) rating, indicating no moisture sensitivity constraints during storage or handling.

Frequently Asked Questions (FAQ)

Q: Can the 1KSMB91A be used as a direct replacement for the 1KSMB91 in existing designs?

A: Yes. The 1KSMB91A is electrically and mechanically equivalent to the 1KSMB91. All voltage ratings, current specifications, and package dimensions are identical, enabling direct substitution without circuit redesign.

Q: What is the primary reason for substituting the 1KSMB91?

A: The 1KSMB91 is classified as obsolete. The 1KSMB91A provides equivalent functionality with active product status, ensuring continued availability and supply chain support.

Q: Are there any differences in operating temperature ranges between the two parts?

A: The 1KSMB91A operates across a wider temperature range (-55°C ~ 175°C) compared to the 1KSMB91 (-65°C ~ 150°C). This extended range provides additional thermal margin but does not affect substitution compatibility for applications within the original part's temperature specification.

Q: Do both parts meet RoHS compliance requirements?

A: Yes. The 1KSMB91 is RoHS Compliant, and the 1KSMB91A is ROHS3 Compliant. Both parts satisfy current environmental and regulatory standards.

Q: Is the DO-214AA package identical between both parts?

A: Yes. Both the 1KSMB91 and 1KSMB91A use the DO-214AA (SMB) surface mount package. PCB footprints, solder pad layouts, and thermal characteristics are identical.

Q: What is the moisture sensitivity level for the 1KSMB91A?

A: The 1KSMB91A maintains MSL 1 (Unlimited) rating, indicating no moisture sensitivity constraints. Standard storage and handling procedures apply without special desiccant or humidity control requirements.

Q: Are there any differences in peak pulse power dissipation?

A: No. Both parts are rated for 1000W peak pulse power dissipation under 10/1000µs pulse conditions, ensuring equivalent thermal performance in transient suppression applications.