BZX85B39-TAP Equivalent & Substitute Parts

Part Overview

The BZX85B39-TAP is a Zener diode rated at 39 V nominal voltage with 1.3 W maximum power dissipation, manufactured by Vishay General Semiconductor - Diodes Division. This through-hole component operates across a temperature range of -55°C to 175°C and carries AEC-Q101 automotive qualification. The part is currently active in production with 649 pieces in stock. Equivalent and substitute parts are identified when electrical parameters align within acceptable tolerances and mechanical compatibility is maintained for the DO-41 axial package format.

Substiute Parts

BZX85B39-TAP

Vishay General Semiconductor - Diodes DivisionIn Stock: 727BZX85B39-TAP Datasheet

Current PartRFQ

1N4754A

Lumimax Optoelectronic TechnologyIn Stock: 60241N4754A Datasheet

MFR RecommendedRFQ

1N4754A-T50A

onsemiIn Stock: 62911N4754A-T50A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZX85B39-TAP is determined by the following critical parameters:

Electrical Compatibility Criteria:

• Zener voltage must be 39 V nominal
• Package format must be DO-41 axial through-hole
• Operating temperature range must encompass or exceed the application requirements
• RoHS and REACH compliance status must be maintained

Acceptable Parameter Variations:

• Tolerance: The BZX85B39-TAP specifies ±2%, while substitute parts may have ±5% tolerance. This variation is acceptable when circuit design accounts for the wider tolerance band.
• Power Rating: Substitute parts rated at 1 W are acceptable for applications where the BZX85B39-TAP's 1.3 W rating is not a minimum requirement.
• Impedance: Variations between 50 Ohms and 60 Ohms are acceptable for standard zener diode applications.
• Reverse Leakage Current: Substitute parts with higher leakage specifications (5 µA vs. 500 nA) are acceptable when circuit design does not depend on ultra-low leakage performance.

Mechanical Compatibility: All substitute parts must use the DO-41 axial package format to ensure direct physical and electrical compatibility with existing PCB layouts and through-hole mounting requirements.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: BZX85B39-TAP

The BZX85B39-TAP remains the primary choice for applications requiring automotive-grade components. This part carries AEC-Q101 qualification, which certifies compliance with automotive reliability standards. The ±2% tolerance specification provides tighter voltage regulation compared to substitute options. The 1.3 W power rating offers additional margin for applications with higher power dissipation requirements. This part is suitable for automotive and industrial applications where qualification status is mandatory.

Secondary Selection: 1N4754A-T50A (onsemi)

The 1N4754A-T50A is the preferred substitute when the BZX85B39-TAP is unavailable. This part maintains ROHS3 compliance and carries active product status. The operating temperature range of -65°C to 200°C exceeds the BZX85B39-TAP specification, providing broader environmental coverage. The 1 W power rating is acceptable for applications where the additional 0.3 W margin of the primary part is not required. This part is supplied in Cut Tape (CT) packaging, suitable for automated assembly processes.

Tertiary Selection: 1N4754A (Lumimax)

The 1N4754A from Lumimax provides electrical equivalence with 39 V nominal voltage and identical package format. This part is suitable for non-automotive applications where AEC-Q101 qualification is not required. The extended temperature range and RoHS compliance support general industrial use. Higher inventory availability (5990 pieces) may provide supply chain advantages in high-volume procurement scenarios.

Compliance Considerations:

All three parts maintain REACH Unaffected status and comply with RoHS directives. The BZX85B39-TAP and 1N4754A-T50A both carry ROHS3 certification. Selection should prioritize the BZX85B39-TAP for automotive applications and the 1N4754A-T50A for general industrial applications requiring equivalent performance with broader temperature coverage.

Frequently Asked Questions (FAQ)

Q: Can the 1N4754A substitute directly for the BZX85B39-TAP in automotive applications?

A: The 1N4754A from Lumimax lacks automotive qualification (AEC-Q101). For automotive applications, the 1N4754A-T50A from onsemi is the appropriate substitute, as it maintains active product status and RoHS3 compliance. However, the absence of AEC-Q101 qualification on the 1N4754A-T50A may require design review for safety-critical automotive systems.

Q: What is the impact of the ±5% tolerance on substitute parts compared to the ±2% tolerance of the BZX85B39-TAP?

A: The wider ±5% tolerance on substitute parts (1N4754A and 1N4754A-T50A) results in a zener voltage range of 37.05 V to 40.95 V, compared to 38.22 V to 39.78 V for the BZX85B39-TAP. Circuit designs must accommodate this wider tolerance band. Applications requiring precise voltage regulation should specify the BZX85B39-TAP.

Q: Are the 1 W substitute parts suitable for applications designed for the 1.3 W BZX85B39-TAP?

A: The 1 W power rating of substitute parts is acceptable only when circuit analysis confirms that maximum power dissipation does not exceed 1 W. Applications with higher power dissipation requirements must use the BZX85B39-TAP or verify that substitute parts operate within safe thermal limits.

Q: What is the significance of the reverse leakage current difference between the BZX85B39-TAP and substitute parts?

A: The BZX85B39-TAP specifies 500 nA reverse leakage at 30 V, while substitute parts specify 5 µA at 29.7 V. This tenfold difference is acceptable for standard zener applications. Applications requiring ultra-low leakage performance, such as precision analog circuits or high-impedance measurement systems, should use the BZX85B39-TAP.

Q: Can substitute parts be used interchangeably in existing PCB designs?

A: Yes. All substitute parts use the DO-41 axial package format, which is mechanically and electrically compatible with existing through-hole PCB layouts. Direct physical substitution is possible without PCB redesign. However, electrical performance differences (tolerance, power rating, leakage current) must be evaluated against circuit requirements.

Q: What is the difference between the Lumimax 1N4754A and the onsemi 1N4754A-T50A?

A: Both parts share identical electrical specifications (39 V, ±5%, 1 W). The primary differences are manufacturer, packaging format (Lumimax supplied in standard packaging; onsemi supplied in Cut Tape), and compliance certifications (onsemi carries ROHS3 certification). The onsemi part is preferred for applications requiring documented ROHS3 compliance.

Q: Is the extended operating temperature range of substitute parts (-65°C to 200°C) an advantage over the BZX85B39-TAP (-55°C to 175°C)?

A: The extended temperature range of substitute parts provides broader environmental coverage and may be advantageous for applications operating at temperature extremes. However, this does not compensate for the loss of automotive qualification (AEC-Q101) on the Lumimax part or the absence of automotive-grade certification on the onsemi part for safety-critical automotive systems.