BZX55C47 Equivalent & Substitute Parts

Part Overview

The BZX55C47 is a 47 V Zener diode manufactured by onsemi, rated for 500 mW power dissipation in a DO-35 through-hole axial package. This component is classified as obsolete, necessitating identification of active equivalent parts for new designs and ongoing production requirements. Substitute parts must maintain the 47 V nominal Zener voltage while accommodating variations in power rating, package form factor, and electrical characteristics within acceptable engineering tolerances.

Substiute Parts

BZX55C47

onsemiIn Stock: 5161BZX55C47 Datasheet

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1N4756A

Lumimax Optoelectronic TechnologyIn Stock: 103191N4756A Datasheet

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1N5368B-TP

Micro Commercial CoIn Stock: 43671N5368B-TP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZX55C47 is determined by the following critical parameters:

Primary Matching Criteria:

• Voltage - Zener (Nom): 47 V (exact match required)
• Mounting Type: Through Hole (axial configuration)
• Operating Temperature Range: Must encompass or exceed -65°C to 200°C

Secondary Compatibility Factors:

• Power - Max: Substitute parts rated at or above 500 mW are acceptable
• Tolerance: ±5% or ±6% are equivalent for circuit design purposes
• Impedance (Max): Lower impedance values indicate improved performance characteristics
• Package / Case: DO-35, DO-41, and DO-15 are all axial through-hole formats with different thermal capabilities

The two identified substitute parts maintain the 47 V Zener voltage specification and through-hole mounting requirement. Both are currently active products, addressing the obsolescence status of the BZX55C47. Substitutes differ in power rating and package form factor, allowing selection based on thermal and spatial constraints of the application.

Parameter Comparison

Engineering Selection Recommendations

1N4756A Selection Criteria: The 1N4756A is an active product manufactured by Lumimax Optoelectronic Technology with 1 W power rating in a DO-41 package. This part provides a moderate power increase over the BZX55C47 while maintaining identical operating temperature range (-65°C to 200°C). The DO-41 package offers improved thermal dissipation compared to DO-35. Tolerance specification of ±5% meets or exceeds the original ±6% requirement. This substitute is suitable for applications requiring modest power increases without significant thermal management modifications.

1N5368B-TP Selection Criteria: The 1N5368B-TP is an active product manufactured by Micro Commercial Co with 5 W power rating in a DO-15 package. This part delivers substantially higher power dissipation capability and lower impedance (25 Ohms versus 110 Ohms), resulting in improved voltage regulation characteristics. The DO-15 package provides maximum thermal capability among the three options. Operating temperature range is -55°C to 150°C, which is narrower than the original specification. This substitute is appropriate for applications with elevated thermal requirements or where superior voltage regulation performance is necessary. Temperature range limitation must be evaluated against application requirements.

Compliance Considerations: Both substitute parts carry REACH Unaffected status and EAR99 ECCN classification, matching the original BZX55C47. The 1N5368B-TP holds ROHS3 Compliant certification, while the 1N4756A status is not specified in provided data. Both parts are currently in active production with substantial inventory availability.

Frequently Asked Questions (FAQ)

Q: Can the 1N4756A directly replace the BZX55C47 in existing designs?

A: The 1N4756A maintains the 47 V Zener voltage and through-hole mounting configuration. The primary design consideration is package form factor change from DO-35 to DO-41, which affects board layout and thermal characteristics. The 1 W power rating exceeds the original 500 mW specification, providing design margin. Electrical performance is compatible for applications operating within the -65°C to 200°C temperature range.

Q: What are the thermal implications of switching from DO-35 to DO-41 or DO-15 packages?

A: The DO-35 package has the smallest thermal footprint and lowest power dissipation capability (500 mW). The DO-41 package (1N4756A) provides intermediate thermal performance with 1 W rating. The DO-15 package (1N5368B-TP) offers the largest thermal mass and highest power rating (5 W). Selection depends on circuit power dissipation requirements and available board space for component placement.

Q: Are there impedance differences that affect circuit performance?

A: Yes. The BZX55C47 has maximum impedance of 110 Ohms. The 1N4756A reduces this to 80 Ohms, and the 1N5368B-TP further reduces it to 25 Ohms. Lower impedance provides better voltage regulation and faster transient response. Applications requiring superior voltage stability benefit from lower impedance substitutes.

Q: Does the 1N5368B-TP operating temperature range of -55°C to 150°C create compatibility issues?

A: The 1N5368B-TP temperature range is narrower than the original BZX55C47 specification (-65°C to 200°C). This substitute is compatible only with applications operating within the -55°C to 150°C window. Applications requiring the full -65°C to 200°C range must use the 1N4756A or identify alternative parts with extended temperature specifications.

Q: What is the significance of tolerance differences between ±6% and ±5%?

A: Both tolerance specifications are acceptable for Zener diode applications. The ±5% tolerance of substitute parts represents equivalent or improved precision compared to the original ±6% specification. This does not create compatibility concerns and may provide tighter voltage regulation in some circuit configurations.

Q: How do reverse leakage current differences impact circuit design?

A: The BZX55C47 specifies 100 nA reverse leakage at 35 V. The 1N4756A increases to 5 µA at 35.8 V, while the 1N5368B-TP is 500 nA at 35.8 V. Higher leakage current affects standby power consumption and circuit biasing. Applications with strict leakage requirements should evaluate the 1N5368B-TP as a compromise between the original and 1N4756A specifications.

Q: Are packaging format changes (DO-35 to DO-41 or DO-15) the only board-level considerations?

A: Package changes affect component footprint, lead spacing, and thermal dissipation path to the PCB. The DO-35 is the smallest format, while DO-41 and DO-15 are progressively larger. Board layout modifications may be required to accommodate different lead configurations. Thermal design must account for increased power dissipation capability of substitute parts if utilized at higher power levels.