BZX85B43-TAP Equivalent & Substitute Parts

Part Overview

The BZX85B43-TAP is an automotive-grade Zener diode manufactured by Vishay General Semiconductor - Diodes Division. This through-hole component operates at a nominal Zener voltage of 43 V with a maximum power dissipation of 1.3 W. The device is qualified to AEC-Q101 automotive standards and maintains active product status. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required for applications where the primary part is unavailable or when design flexibility permits alternative sourcing.

Substiute Parts

BZX85B43-TAP

Vishay General Semiconductor - Diodes DivisionIn Stock: 1014BZX85B43-TAP Datasheet

Current PartRFQ

1N4755A

Lumimax Optoelectronic TechnologyIn Stock: 43431N4755A Datasheet

MFR RecommendedRFQ

BZX79-C43,133

Nexperia USA Inc.In Stock: 10909BZX79-C43,133 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZX85B43-TAP is determined by the following critical parameters:

Primary Substitution Criteria:

• Zener voltage nominal value: 43 V (exact match required)
• Mounting type: Through Hole (mechanical compatibility)
• Package compatibility: DO-41 series packages (physical fit)
• RoHS compliance status (regulatory requirement)

Secondary Compatibility Factors:

• Power dissipation capacity (minimum 1.3 W preferred; lower ratings acceptable for reduced-power applications)
• Voltage tolerance (±2% preferred; ±5% acceptable with design margin verification)
• Operating temperature range (minimum -55°C to 175°C required for automotive applications)
• Impedance characteristics (affects circuit response; higher impedance acceptable in most applications)

The identified substitute parts maintain the 43 V Zener voltage specification and through-hole mounting configuration. Variations in power rating, tolerance, and impedance reflect different manufacturing series and design approaches while preserving core functional compatibility.

Parameter Comparison

Engineering Selection Recommendations

BZX85B43-TAP (Primary Selection)

The BZX85B43-TAP is the specified component for applications requiring automotive-grade reliability. This part carries AEC-Q101 qualification and automotive grade designation, meeting stringent automotive industry standards. The ±2% voltage tolerance provides superior voltage regulation accuracy. The 1.3 W power rating and 50 Ohm impedance specification support high-performance circuit designs. ROHS3 compliance and unlimited moisture sensitivity level (MSL 1) confirm suitability for production environments without special handling requirements.

1N4755A (Substitute - Equivalent Power Rating)

The 1N4755A maintains the 43 V Zener voltage and offers comparable 1 W power dissipation. This part is suitable for applications where automotive qualification is not mandatory. The ±5% voltage tolerance is acceptable in designs with adequate margin. The extended operating temperature range (-65 to 200°C) exceeds the primary part specification. RoHS compliance is confirmed. This substitute is mechanically compatible with DO-41 package requirements.

BZX79-C43,133 (Substitute - Reduced Power Rating)

The BZX79-C43,133 maintains the 43 V Zener voltage with reduced 400 mW power dissipation. This part is applicable to low-power circuit designs where the full 1.3 W capacity is not required. The ±5% voltage tolerance and higher impedance (150 Ohms) reflect the lower power classification. ROHS3 compliance and unlimited MSL confirm production compatibility. The DO-35 package differs from the primary part; physical board layout verification is necessary for mechanical fit.

Frequently Asked Questions (FAQ)

Q: Can the 1N4755A directly replace the BZX85B43-TAP in automotive applications?

A: The 1N4755A maintains electrical compatibility through identical 43 V Zener voltage and comparable 1 W power rating. However, the primary part carries AEC-Q101 automotive qualification while the 1N4755A does not. Automotive application suitability depends on specific design requirements and qualification protocols established for the end application.

Q: What is the impact of the ±5% tolerance in substitute parts compared to the ±2% tolerance of the BZX85B43-TAP?

A: The ±2% tolerance of the primary part provides tighter voltage regulation (±0.86 V at 43 V nominal). Substitute parts with ±5% tolerance provide ±2.15 V regulation window. Circuit designs must accommodate this wider tolerance band through appropriate margin allocation in voltage reference and protection circuits.

Q: Is the BZX79-C43,133 suitable for applications designed for 1.3 W power dissipation?

A: The BZX79-C43,133 is rated for 400 mW maximum power dissipation, which is approximately 31% of the primary part's 1.3 W rating. This substitute is applicable only to applications where actual power dissipation does not exceed 400 mW. Applications requiring the full 1.3 W capacity must use the primary part or the 1N4755A.

Q: Are there package compatibility issues between the substitute parts and the BZX85B43-TAP?

A: The BZX85B43-TAP and 1N4755A both use DO-41 packages and are mechanically interchangeable. The BZX79-C43,133 uses a DO-35 package, which has different physical dimensions. Board layout and component footprint verification is required before substituting the BZX79-C43,133.

Q: What is the significance of the reverse leakage current differences among these parts?

A: The BZX85B43-TAP specifies 500 nA reverse leakage at 33 V. The 1N4755A specifies 5 µA at 32.7 V, and the BZX79-C43,133 specifies 55 µA at 700 mV. Higher reverse leakage affects circuit performance in high-impedance applications and temperature-sensitive designs. The primary part's lower leakage current provides superior performance in precision voltage reference circuits.

Q: Do all three parts meet RoHS compliance requirements?

A: Yes. The BZX85B43-TAP and BZX79-C43,133 are ROHS3 compliant. The 1N4755A is RoHS compliant. All three parts meet current RoHS regulatory requirements for electronic component manufacturing and assembly.

Q: What is the operating temperature range consideration for substitute selection?

A: The BZX85B43-TAP operates from -55°C to 175°C. Both substitute parts extend this range to -65 to 200°C. For applications operating within the primary part's temperature range, all three parts are compatible. Applications requiring extended temperature operation benefit from the substitute parts' wider range.