BZX85C56 Equivalent & Substitute Parts

Part Overview

The BZX85C56 is a through-hole zener diode rated at 56 V nominal voltage with 1 W maximum power dissipation, manufactured by onsemi in the DO-41 package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The BZX85C56 operates across a wide temperature range from -65°C to 200°C and maintains ±7% voltage tolerance, suitable for voltage regulation and protection applications in electronic circuits.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	56	V
Power - Max	1	W
Tolerance	±7%	-
Impedance (Max)	120	Ohms
Current - Reverse Leakage @ Vr	500 nA @ 39 V	-
Voltage - Forward (Max) @ If	1.2 V @ 200 mA	-
Operating Temperature Range	-65°C to 200°C	-
Mounting Type	Through Hole	-
Package / Case	DO-204AL, DO-41, Axial	-

Substitute Part Grouping Explanation

Substitution of the BZX85C56 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Zener voltage: 56 V nominal
Package type: DO-41 / DO-204AL through-hole axial configuration
Mounting type: Through hole

Secondary Compatibility Factors:

Power rating: Equal to or greater than 1 W
Voltage tolerance: ±7% or tighter
Operating temperature range: Must encompass or exceed -65°C to 200°C
Impedance characteristics: Maximum 120 Ohms or lower preferred
Reverse leakage current: 500 nA @ 39 V or lower preferred

Substitute parts are grouped based on whether they meet the minimum electrical specifications while maintaining mechanical compatibility. Parts with higher power ratings, tighter tolerances, or improved temperature ranges are considered direct substitutes. Parts with lower power ratings or narrower temperature ranges require application-specific evaluation.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Reverse Leakage	Vf (Max) @ If	Temp Range	Status
BZX85C56	onsemi	56 V	±7%	1 W	120 Ω	500 nA @ 39 V	1.2 V @ 200 mA	-65°C to 200°C	Obsolete
1N4758A	SMC Diode Solutions	56 V	±5%	1 W	110 Ω	5 µA @ 42.6 V	1.2 V @ 200 mA	-65°C to 200°C	Obsolete
1N5087	Microchip Technology	56 V	±5%	3 W	70 Ω	1 µA @ 42.6 V	Not specified	-65°C to 175°C	Active
1N5943B3P-TP	Micro Commercial Co	56 V	±5%	3 W	86 Ω	1 µA @ 42.6 V	1.5 V @ 200 mA	-55°C to 150°C	Active
1N5943BP-TP	Micro Commercial Co	56 V	±5%	1.5 W	86 Ω	1 µA @ 42.6 V	1.5 V @ 200 mA	-55°C to 175°C	Active
2EZ56D5	Microsemi Corporation	56 V	±5%	2 W	55 Ω	500 nA @ 42.6 V	1.2 V @ 200 mA	-65°C to 150°C	Active
2EZ56D5-TP	Micro Commercial Co	56 V	±5%	2 W	55 Ω	500 nA @ 42.6 V	1.2 V @ 200 mA	-55°C to 150°C	Active
BZV85-C56,113	NXP Semiconductors	56 V	±5%	1.3 W	150 Ω	50 nA @ 39 V	1 V @ 50 mA	-65°C to 200°C	Active
BZV85-C56,133	NXP USA Inc.	56 V	±5%	1.3 W	150 Ω	50 nA @ 39 V	1 V @ 50 mA	-65°C to 200°C	Active

Engineering Selection Recommendations

Direct Substitutes (Preferred):

The BZV85-C56,113 and BZV85-C56,133 from NXP Semiconductors and NXP USA Inc. respectively are the most suitable direct substitutes. Both parts maintain the full operating temperature range of -65°C to 200°C, matching the BZX85C56 specification. These parts feature tighter voltage tolerance (±5%), improved impedance characteristics (150 Ω maximum), and active product status ensuring long-term availability. The 1.3 W power rating exceeds the 1 W requirement of the original part.

Secondary Substitutes (Application-Dependent):

The 2EZ56D5 from Microsemi Corporation and 2EZ56D5-TP from Micro Commercial Co provide enhanced power dissipation at 2 W with superior impedance performance (55 Ω maximum). Both maintain the -65°C lower temperature limit and feature ±5% tolerance. The 2EZ56D5 operates to 150°C, while the 2EZ56D5-TP operates to 150°C (TJ). These parts are suitable for applications requiring higher power handling within the specified voltage range.

Higher Power Alternatives:

The 1N5087 from Microchip Technology and 1N5943B3P-TP from Micro Commercial Co offer 3 W power ratings with improved impedance (70 Ω and 86 Ω respectively). The 1N5087 maintains the -65°C lower temperature limit and operates to 175°C. These parts are appropriate for designs requiring significant thermal margin or higher current dissipation.

Obsolete Alternatives:

The 1N4758A from SMC Diode Solutions is functionally equivalent to the BZX85C56 with matching 1 W power rating and full temperature range (-65°C to 200°C), but carries obsolete product status. This part should not be selected for new designs.

All substitute parts listed maintain REACH compliance and EAR99 export classification consistent with the original BZX85C56.

Frequently Asked Questions (FAQ)

Q: Can the BZX85C56 be replaced with any 56 V zener diode?

A: No. Substitution requires matching the 56 V nominal zener voltage, DO-41 through-hole package configuration, and maintaining electrical specifications within acceptable limits. Power rating, impedance, temperature range, and tolerance must be evaluated for the specific application.

Q: What is the difference between the BZV85-C56,113 and BZV85-C56,133?

A: Both parts are electrically identical 56 V, 1.3 W zener diodes with ±5% tolerance and -65°C to 200°C operating range. The difference lies in manufacturer designation: BZV85-C56,113 is from NXP Semiconductors, while BZV85-C56,133 is from NXP USA Inc. Both are active products suitable for direct substitution.

Q: Why do some substitute parts have higher power ratings than the original BZX85C56?

A: Higher power ratings provide thermal margin and allow the component to operate at lower junction temperatures under the same current conditions. This improves reliability and extends component life. Parts with 1.5 W, 2 W, or 3 W ratings are backward-compatible with 1 W applications.

Q: Is the 1N5087 a suitable substitute despite its lower maximum operating temperature?

A: The 1N5087 operates to 175°C, which is 25°C below the BZX85C56 specification of 200°C. This part is suitable only if the application does not require operation above 175°C. For designs requiring the full 200°C capability, select BZV85-C56,113, BZV85-C56,133, or 1N4758A.

Q: What does the ±5% tolerance mean compared to the original ±7%?

A: Tolerance specifies the allowable deviation from the nominal 56 V zener voltage. The ±5% tolerance on substitute parts is tighter than the original ±7%, meaning the actual voltage will be closer to 56 V. This provides better voltage regulation performance and is a beneficial characteristic for substitution.

Q: Can I use the 2EZ56D5-TP in place of the BZX85C56 if my circuit operates below 150°C?

A: Yes. The 2EZ56D5-TP is suitable for applications where the maximum operating temperature does not exceed 150°C. This part offers superior impedance (55 Ω) and double the power rating (2 W), making it an excellent choice for designs with thermal headroom below 150°C.

Q: Are all substitute parts RoHS compliant?

A: The 1N5087 and 2EZ56D5 are explicitly marked as ROHS3 compliant. Other parts do not specify RoHS status in the provided data. Verify RoHS compliance requirements with the component supplier if this is a design requirement.

Q: What is the significance of impedance (Zzt) in zener diode selection?

A: Impedance affects the dynamic voltage regulation characteristics of the zener diode. Lower impedance values provide better voltage stability under varying load conditions. Substitute parts with impedance equal to or lower than the original specification maintain or improve regulation performance.

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