1N976B Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N976B is a 43 V, 500 mW Zener diode manufactured by onsemi in a DO-35 axial through-hole package. This component functions as a voltage regulator and protective device in electronic circuits. The 1N976B is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production requirements. Substitute parts must maintain the same nominal Zener voltage, power dissipation capability, and through-hole mounting characteristics to ensure functional compatibility in existing circuit designs.

Substiute Parts

1N976B

onsemiIn Stock: 9281N976B Datasheet

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1N4755A

Lumimax Optoelectronic TechnologyIn Stock: 43431N4755A Datasheet

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1N976A

Microchip TechnologyIn Stock: 8231N976A Datasheet

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1N976B-1

Microchip TechnologyIn Stock: 10961N976B-1 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1N976B is determined by the following critical parameters:

Electrical Parameters:

• Nominal Zener voltage of 43 V (primary functional requirement)
• Voltage tolerance of ±5% or tighter (ensures regulation accuracy)
• Maximum power dissipation of 500 mW or greater (ensures thermal capability)
• Impedance (Zzt) of 93 Ohms or lower (ensures dynamic response)
• Reverse leakage current of 5 µA or lower @ 32.7 V (ensures blocking performance)

Mechanical Parameters:

• Through-hole axial mounting configuration (ensures PCB compatibility)
• DO-35 or equivalent package footprint (ensures physical fit)

Environmental Parameters:

• Operating temperature range of -65°C to 175°C minimum (ensures functional operation across specified conditions)

Parts meeting all electrical and mechanical criteria are classified as direct substitutes. Parts with enhanced power ratings or improved specifications remain functionally compatible while providing additional design margin.

Parameter Comparison

Engineering Selection Recommendations

1N976B-1 (Microchip Technology)

The 1N976B-1 is the primary substitute for the obsolete 1N976B. This part maintains identical electrical specifications (43 V nominal, ±5% tolerance, 500 mW power rating, 93 Ohms impedance) and uses the same DO-35 package footprint. The 1N976B-1 is in active production status and carries ROHS3 compliance certification. The reverse leakage current is improved to 500 nA @ 33 V compared to 5 µA @ 32.7 V in the original part. Operating temperature range is -65°C to 175°C, which covers the primary operating window of the original specification. This part is suitable for direct replacement in existing designs without PCB modification.

1N4755A (Lumimax Optoelectronic Technology)

The 1N4755A is a compatible substitute with enhanced power dissipation capability (1 W versus 500 mW). This part maintains the 43 V nominal voltage and ±5% tolerance. The impedance is improved to 70 Ohms. The package is DO-41, which differs from the DO-35 footprint of the original part and requires PCB layout modification. The 1N4755A is in active production and RoHS compliant. This part is suitable for applications requiring higher power dissipation margin or improved dynamic response characteristics.

1N976A (Microchip Technology)

The 1N976A maintains the 43 V nominal voltage and 500 mW power rating with identical impedance (93 Ohms). However, the voltage tolerance is ±10%, which is wider than the original ±5% specification. The package is DO-7, which differs from the DO-35 footprint and requires PCB modification. The 1N976A is in active production but carries RoHS non-compliant status. This part is suitable only when tolerance relaxation and package change are acceptable in the design.

Frequently Asked Questions (FAQ)

Q: Can the 1N976B-1 be used as a direct replacement for the 1N976B without PCB modification?

A: Yes. The 1N976B-1 uses the same DO-35 package footprint and maintains identical electrical specifications (43 V, ±5%, 500 mW, 93 Ohms impedance). No PCB layout changes are required.

Q: What is the primary difference between the 1N976B-1 and the 1N4755A?

A: The 1N976B-1 maintains the original 500 mW power rating in a DO-35 package. The 1N4755A provides double the power dissipation (1 W) but uses a DO-41 package, requiring PCB modification. Both maintain 43 V nominal voltage and ±5% tolerance.

Q: Why does the 1N976A have a ±10% tolerance instead of ±5%?

A: The 1N976A is a different product variant with relaxed tolerance specifications. The wider tolerance may affect voltage regulation accuracy in precision applications. Use only when tolerance relaxation is acceptable.

Q: Can the 1N4755A be used in applications with space constraints?

A: No. The 1N4755A uses a DO-41 package, which is physically larger than the DO-35 package of the original 1N976B. PCB layout modification is required, and space constraints may prevent installation.

Q: What is the impact of improved reverse leakage current in the 1N976B-1?

A: The 1N976B-1 exhibits reverse leakage of 500 nA @ 33 V compared to 5 µA @ 32.7 V in the original part. Lower reverse leakage improves blocking performance and reduces standby current in voltage regulation circuits.

Q: Are all substitute parts RoHS compliant?

A: The 1N976B-1 is ROHS3 compliant and the 1N4755A is RoHS compliant. The 1N976A is RoHS non-compliant. Compliance requirements depend on end-use application and regional regulations.

Q: What is the maximum operating temperature for each substitute?

A: The 1N976B-1 and 1N976A operate to 175°C. The 1N4755A operates to 200°C, matching the original 1N976B specification. Temperature range selection depends on thermal environment requirements.