BZX85B91-TAP Equivalent & Substitute Parts

Part Overview

The BZX85B91-TAP is a 91 V, 1.3 W Zener diode manufactured by Vishay General Semiconductor - Diodes Division in a through-hole DO-204AL (DO-41) axial package. This component is classified as obsolete, though 1171 pieces remain in stock as new original inventory. The part is AEC-Q101 qualified for automotive applications and RoHS3 compliant.

Due to the obsolete product status of the BZX85B91-TAP, equivalent and substitute Zener diodes are necessary for new designs, ongoing production support, and long-term component availability assurance. Substitute parts must maintain the 91 V nominal Zener voltage while accommodating variations in power rating, tolerance, and reverse leakage characteristics within acceptable application parameters.

Substiute Parts

BZX85B91-TAP

Vishay General Semiconductor - Diodes DivisionIn Stock: 1238BZX85B91-TAP Datasheet

Current PartRFQ

1N4763 G

Microsemi CorporationIn Stock: 7261N4763 G Datasheet

MFR RecommendedRFQ

1N4763AG

Microsemi CorporationIn Stock: 9071N4763AG Datasheet

MFR RecommendedRFQ

1N4763AUR

Microchip TechnologyIn Stock: 11711N4763AUR Datasheet

MFR RecommendedRFQ

1N5948AG

Microsemi CorporationIn Stock: 10801N5948AG Datasheet

MFR RecommendedRFQ

1N5948CG

Microsemi CorporationIn Stock: 11201N5948CG Datasheet

MFR RecommendedRFQ

1N5948DG

Microsemi CorporationIn Stock: 10921N5948DG Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZX85B91-TAP is determined by the following critical parameters:

Primary Matching Criteria:

• Voltage - Zener (Nom): 91 V (exact match required)
• Mounting Type: Through Hole (for direct PCB compatibility)
• Package / Case: DO-204AL (DO-41) Axial (for mechanical fit)

Secondary Compatibility Parameters:

• Power - Max: Equal to or greater than 1.3 W
• Impedance (Max): 250 Ohms or lower
• Operating Temperature: Minimum 175°C
• Tolerance: ±2% or tighter (for precision applications)

Acceptable Variations:

• Reverse leakage current may differ from the original specification
• Manufacturer may vary (Microsemi Corporation, Microchip Technology)
• Product status may be Active (preferred over Obsolete)

Substitute parts are grouped into two categories: through-hole axial packages (direct mechanical replacement) and surface-mount alternatives (for design flexibility in new applications).

Parameter Comparison

Engineering Selection Recommendations

For Through-Hole Axial Package Applications (Direct Mechanical Replacement):

The 1N5948 series (1N5948DG, 1N5948CG, 1N5948AG) provides the closest functional equivalence to the BZX85B91-TAP. All three variants maintain the 91 V nominal Zener voltage, through-hole mounting, and DO-204AL (DO-41) axial package. The 1N5948DG offers ±1% tolerance matching the original ±2% specification, while the 1N5948CG provides ±2% tolerance. The 1N5948AG operates at ±10% tolerance. All three feature 1.25 W maximum power rating, exceeding the original 1.3 W specification, and lower impedance (200 Ohms) compared to the original 250 Ohms. These parts are manufactured by Microsemi Corporation and carry Active product status.

The 1N4763 series (1N4763AG, 1N4763G) also maintains the 91 V voltage and through-hole DO-204AL (DO-41) package but operates at reduced 1 W maximum power. The 1N4763AG provides ±5% tolerance, while 1N4763G operates at ±10% tolerance. These parts are suitable for applications where the 1.3 W power specification is not a limiting constraint.

For Surface-Mount Applications (Design Flexibility):

The 1N4763AUR, manufactured by Microchip Technology, provides a 91 V, 1 W Zener diode in a surface-mount DO-213AB (MELF) package with ±5% tolerance. This part is applicable to new designs requiring surface-mount technology but does not provide direct mechanical replacement for through-hole PCB layouts.

Compliance Considerations:

All substitute parts carry RoHS non-compliant status, whereas the original BZX85B91-TAP is RoHS3 compliant. Applications subject to RoHS3 regulatory requirements must account for this compliance difference. All substitute parts maintain REACH Unaffected status and EAR99 export classification, matching the original part.

The original BZX85B91-TAP carries AEC-Q101 automotive qualification. Substitute parts do not explicitly list automotive qualification in the provided specifications. Applications requiring automotive-grade components must evaluate this qualification gap against specific application requirements.

Frequently Asked Questions (FAQ)

Q: Can the 1N4763 series substitute for the BZX85B91-TAP in all applications?

A: The 1N4763 series maintains the 91 V nominal Zener voltage and through-hole DO-204AL (DO-41) package, enabling mechanical and electrical compatibility. However, the 1 W maximum power rating is lower than the original 1.3 W specification. Substitution is valid only for applications where power dissipation does not exceed 1 W. Reverse leakage current is higher (5 µA versus 500 nA), which may affect precision voltage regulation applications.

Q: What is the difference between 1N5948DG, 1N5948CG, and 1N5948AG?

A: All three parts are 91 V, 1.25 W Zener diodes in DO-204AL (DO-41) packages manufactured by Microsemi Corporation. The primary difference is tolerance specification: 1N5948DG operates at ±1%, 1N5948CG at ±2%, and 1N5948AG at ±10%. For applications requiring precision voltage regulation, the 1N5948DG is preferred. All three feature identical impedance (200 Ohms) and reverse leakage current (1 µA @ 69.2 V).

Q: Is the 1N4763AUR a direct replacement for the BZX85B91-TAP?

A: The 1N4763AUR is not a direct mechanical replacement. While it maintains the 91 V nominal Zener voltage and ±5% tolerance, it is a surface-mount component in a DO-213AB (MELF) package, whereas the original is a through-hole axial component. The 1N4763AUR is applicable only to new designs utilizing surface-mount technology or hybrid layouts.

Q: Why do substitute parts have higher reverse leakage current than the original?

A: Reverse leakage current variation is a normal characteristic across different Zener diode manufacturers and product lines. The 1N4763 series exhibits 5 µA @ 69.2 V compared to the original 500 nA @ 68 V. The 1N5948 series exhibits 1 µA @ 69.2 V, representing a middle ground. Applications sensitive to leakage current must evaluate this parameter against circuit requirements.

Q: Are substitute parts suitable for automotive applications?

A: The original BZX85B91-TAP carries AEC-Q101 automotive qualification. Substitute parts do not explicitly list automotive qualification in the provided specifications. Applications requiring automotive-grade components must verify qualification status with the manufacturer or evaluate the application against specific automotive standards independently.

Q: What is the impact of RoHS compliance differences?

A: The original BZX85B91-TAP is RoHS3 compliant, while all substitute parts are RoHS non-compliant. Applications subject to RoHS3 regulatory requirements (primarily in European markets) must account for this compliance difference. Non-compliant parts may not be acceptable for products marketed in regions with mandatory RoHS3 enforcement.

Q: Can I use a 1 W Zener diode where a 1.3 W part is specified?

A: Substitution depends on actual power dissipation in the application. If the circuit dissipates less than 1 W, a 1 W rated part is acceptable. If the circuit approaches or exceeds 1 W dissipation, the 1.25 W rated 1N5948 series is required to maintain adequate thermal margin and component reliability.

Q: What does impedance (Zzt) mean in Zener diode specifications?

A: Impedance (Zzt) is the dynamic impedance of the Zener diode in the reverse-bias region. Lower impedance indicates better voltage regulation characteristics and reduced output impedance. The original part specifies 250 Ohms maximum, while the 1N5948 series specifies 200 Ohms maximum, indicating superior regulation performance in the substitute.