1N5256 Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N5256 is a 30 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 1N5256 functions as a voltage regulation and transient protection element in electronic circuits requiring 30 V Zener reference characteristics.

Due to obsolete status, locating original 1N5256 units from primary inventory channels presents supply chain challenges. Substitute parts with identical electrical specifications and compatible packaging enable continued circuit functionality and design continuity.

Substiute Parts

1N5256

SMC Diode SolutionsIn Stock: 8201N5256 Datasheet

Current PartRFQ

1N5256B TR PBFREE

Central Semiconductor CorpIn Stock: 51561N5256B TR PBFREE Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1N5256 is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Matching Parameters:

• Zener voltage: 30 V nominal
• Power dissipation rating: 500 mW
• Package type: DO-35 axial through-hole
• Impedance (Zzt): 49 Ohms maximum
• Reverse leakage current: 100 nA @ 23 V
• Forward voltage: 1.1 V @ 200 mA

Acceptable Variations:

• Zener voltage tolerance: Original part specifies no tolerance; substitute parts with ±5% tolerance remain functionally equivalent
• Operating temperature range: Substitute parts with extended lower temperature limits (-65°C) provide enhanced thermal performance without compromising upper limit compatibility
• Product status: Active production status of substitute parts ensures ongoing availability

The 1N5256B TR PBFREE from Central Semiconductor Corp satisfies all critical matching parameters and provides superior supply chain availability through active production status.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: 1N5256B TR PBFREE

The 1N5256B TR PBFREE from Central Semiconductor Corp is the direct functional equivalent for the obsolete 1N5256. Selection of this substitute is based on the following engineering criteria:

Electrical Equivalence: All critical electrical parameters match the original specification: 30 V Zener voltage, 500 mW power rating, 49 Ohms impedance, and identical leakage and forward voltage characteristics.

Package Compatibility: Both components use DO-35 axial through-hole packaging, ensuring direct PCB layout compatibility without redesign.

Product Status: Active production status of the 1N5256B TR PBFREE ensures reliable supply chain access and long-term availability, eliminating obsolescence risk associated with the original part.

Compliance Certifications: The substitute part carries ROHS3 compliance certification, meeting current regulatory requirements for electronic component manufacturing and distribution. Both parts maintain REACH Unaffected status and identical Moisture Sensitivity Level (MSL) ratings.

Operating Temperature: The substitute part extends the lower operating temperature limit to -65°C while maintaining the 200°C upper limit, providing enhanced thermal performance envelope without compromising circuit operation.

Frequently Asked Questions (FAQ)

Q: Can the 1N5256B TR PBFREE directly replace the 1N5256 without circuit modification?

A: Yes. The 1N5256B TR PBFREE provides identical electrical specifications across all critical parameters: 30 V Zener voltage, 500 mW power rating, 49 Ohms impedance, and matching leakage and forward voltage characteristics. The DO-35 axial through-hole package is mechanically identical, enabling direct substitution without PCB redesign.

Q: What is the significance of the ±5% tolerance specification on the 1N5256B TR PBFREE?

A: The original 1N5256 does not specify a tolerance value. The 1N5256B TR PBFREE specifies ±5% tolerance on the 30 V Zener voltage, meaning the actual Zener voltage will fall between 28.5 V and 31.5 V. This tolerance range is standard for Zener diodes and does not affect functional equivalence in typical voltage regulation and transient protection applications.

Q: Does the extended operating temperature range of the 1N5256B TR PBFREE affect compatibility?

A: No. The substitute part extends the lower operating temperature limit to -65°C while maintaining the 200°C upper limit. This expanded range provides enhanced thermal performance and does not introduce compatibility issues. Circuits designed for the original part operate within the substitute part's temperature envelope.

Q: What is the difference between the original SMC Diode Solutions 1N5256 and the Central Semiconductor Corp 1N5256B TR PBFREE?

A: Both parts are functionally equivalent Zener diodes with identical electrical specifications. The primary difference is manufacturer source and product status: the original is obsolete (discontinued production), while the substitute is in active production. The substitute also includes ROHS3 compliance certification and specified Zener voltage tolerance.

Q: Is the DO-35 package the same across both parts?

A: Yes. Both the 1N5256 and 1N5256B TR PBFREE use the DO-35 axial through-hole package (also designated DO-204AH). The physical dimensions, lead configuration, and PCB mounting characteristics are identical, enabling direct component substitution without layout changes.

Q: What does "PBFREE" designation indicate on the 1N5256B TR PBFREE part number?

A: PBFREE indicates lead-free construction, meaning the component does not contain lead in its solder connections or internal structure. This designation reflects compliance with ROHS3 regulations and modern manufacturing standards for electronic components.

Q: Are there any electrical performance differences between the two parts in circuit operation?

A: No. The electrical performance characteristics are identical: 30 V Zener voltage, 500 mW power dissipation, 49 Ohms impedance, 100 nA reverse leakage current, and 1.1 V forward voltage. Circuit behavior and performance are equivalent.