1N5254B Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N5254B is a 27 V, 500 mW Zener diode in DO-35 axial through-hole packaging manufactured by SMC Diode Solutions. This component is classified as obsolete, indicating discontinued production and limited availability from original sources. The 1N5254B serves voltage regulation and protection applications requiring precise 27 V reference voltage with ±5% tolerance. Identification of equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production requirements for legacy and new designs utilizing this voltage specification.

Substiute Parts

1N5254B

SMC Diode SolutionsIn Stock: 15041N5254B Datasheet

Current PartRFQ

1N5254B TR PBFREE

Central Semiconductor CorpIn Stock: 86111N5254B TR PBFREE Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1N5254B is determined by strict equivalence across the following critical parameters:

Zener Voltage (Vz): 27 V nominal with ±5% tolerance is the primary functional requirement. All substitute parts must maintain this exact voltage specification to ensure proper circuit operation in voltage regulation and protection applications.

Power Dissipation (Pmax): 500 mW maximum power rating establishes the thermal and current handling capability. Substitute parts must support this power level without exceeding thermal limits.

Package and Mounting: DO-35 axial through-hole packaging is mandatory for mechanical and electrical compatibility with existing PCB layouts and assembly processes.

Electrical Characteristics: Forward voltage (Vf), impedance (Zzt), and reverse leakage current must remain within specified ranges to maintain circuit performance and stability.

Environmental and Compliance Status: Operating temperature range, RoHS compliance, and REACH status determine suitability for specific application environments and regulatory jurisdictions.

The substitute part 1N5254B TR PBFREE, manufactured by Central Semiconductor Corp, meets all critical parameter requirements and is classified as active product status, providing superior supply chain availability compared to the obsolete original part.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: 1N5254B TR PBFREE (Central Semiconductor Corp)

The 1N5254B TR PBFREE is the direct functional equivalent for the obsolete 1N5254B. Selection of this substitute is based on the following engineering criteria:

Product Status: The substitute part maintains active production status, ensuring reliable supply chain availability and long-term sourcing capability. The original 1N5254B is obsolete, creating supply constraints for new production and design continuity.

Electrical Equivalence: All critical electrical parameters—Zener voltage, power rating, impedance, and forward voltage—are identical to the original part. This ensures drop-in compatibility without circuit redesign or performance degradation.

Compliance and Certifications: The substitute part is ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic components in most jurisdictions. The original part's compliance status is not specified, creating potential regulatory risk.

Operating Temperature Range: The substitute part extends the operating temperature range to -65°C to 200°C, providing enhanced performance capability in extreme temperature environments compared to the original specification.

Reverse Leakage Current: The substitute part exhibits higher reverse leakage current (100 µA @ 21 V versus 100 nA @ 20 V). This difference is acceptable for voltage regulation and protection applications where leakage current does not significantly impact circuit performance. Applications requiring ultra-low leakage specifications require detailed circuit analysis.

Packaging and Mechanical Compatibility: Both parts utilize identical DO-35 axial through-hole packaging, ensuring mechanical compatibility with existing PCB layouts and assembly processes without modification.

Frequently Asked Questions (FAQ)

Q: Can the 1N5254B TR PBFREE be used as a direct replacement for the 1N5254B in existing designs?

A: Yes. The 1N5254B TR PBFREE is electrically and mechanically equivalent to the 1N5254B across all critical parameters: 27 V Zener voltage, 500 mW power rating, ±5% tolerance, and DO-35 axial through-hole packaging. No circuit modifications are required for substitution.

Q: What is the significance of the higher reverse leakage current in the substitute part?

A: The substitute part exhibits reverse leakage current of 100 µA @ 21 V compared to 100 nA @ 20 V in the original part. This 1000-fold increase is acceptable for standard voltage regulation and protection applications. Applications with stringent leakage requirements or ultra-low standby current specifications require circuit-level analysis to confirm compatibility.

Q: Does the extended operating temperature range of the substitute part affect compatibility?

A: No. The substitute part's extended operating temperature range (-65°C to 200°C) is a superset of the original specification. This provides enhanced performance capability in extreme temperature environments without compromising compatibility in standard operating conditions.

Q: Is the ROHS3 compliance of the substitute part important for my application?

A: ROHS3 compliance indicates the substitute part meets current regulatory requirements for electronic components in most jurisdictions, particularly the European Union and similar regulatory regions. If your application or end market requires RoHS compliance, the substitute part satisfies this requirement. The original part's compliance status is not specified, creating potential regulatory risk.

Q: Are there any packaging differences between the original and substitute parts?

A: No. Both parts utilize identical DO-35 axial through-hole packaging. Mechanical compatibility with existing PCB layouts, assembly processes, and component placement equipment is maintained without modification.

Q: What is the difference between the "TR PBFREE" designation and the standard part number?

A: The "TR PBFREE" designation indicates the part is supplied in cut tape (CT) packaging and is lead-free (PBFREE), complying with RoHS directives. This is a packaging and material specification variant of the base 1N5254B part number, not a functional or electrical difference.

Q: Can I use the substitute part in new designs, or is it only for legacy product support?

A: The 1N5254B TR PBFREE is suitable for both new designs and legacy product support. Active production status ensures long-term availability and supply chain reliability for ongoing manufacturing requirements.