BZX55C15 Equivalent & Substitute Parts

Part Overview

The BZX55C15 is a 15 V Zener diode rated at 500 mW with ±6% tolerance, manufactured by onsemi in a through-hole DO-35 package. This component is classified as obsolete, indicating that direct procurement from the original manufacturer is no longer available. Equivalent and substitute parts are necessary to maintain circuit functionality and ensure continued supply chain access for applications requiring 15 V Zener regulation.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	15	V
Tolerance	±6%	%
Power - Max	500	mW
Impedance (Max)	30	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 11 V
Voltage - Forward (Vf) (Max) @ If	1.3	V @ 100 mA
Operating Temperature	-65 to 200	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—

Substitute Part Grouping Explanation

Substitution of the BZX55C15 is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 15 V (exact match required)
Power - Max: 500 mW (equal or greater)
Mounting Type: Through Hole
Package / Case: DO-35 or DO-204AH compatible

Tolerance Consideration: The BZX55C15 specifies ±6% tolerance. Substitute parts with ±5% tolerance meet this requirement as they represent tighter control and are functionally compatible.

Secondary Substitution Criteria:

Impedance (Max): 30 Ohms (equal or lower)
Operating Temperature: -65°C to 200°C (equal or greater range)
Current - Reverse Leakage: Lower values are acceptable

Substitute Categories:

Direct Equivalents (Full Parameter Match): Parts meeting all primary criteria with identical or superior electrical characteristics and active product status.

Parametric Equivalents (Voltage & Power Match): Parts with matching 15 V nominal voltage and 500 mW power rating, suitable for direct replacement in standard applications.

Similar Parts (Reduced Power Rating): Parts with 15 V nominal voltage but 400 mW power rating. These are suitable for applications where power dissipation does not exceed 400 mW.

Voltage-Adjacent Parts (Nominal Voltage Variation): Parts with nominal voltages within the tolerance band of the original specification. These are listed for reference but require circuit validation.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Vf (Max) @ If	Temp Range	Package	Status
BZX55C15	onsemi	15 V	±6%	500 mW	30 Ω	1.3 V @ 100 mA	-65 to 200°C	DO-35	Obsolete
BZX79C15-T50A	Fairchild Semiconductor	15 V	±5%	500 mW	30 Ω	1.5 V @ 100 mA	-65 to 200°C	DO-35	Active
BZX79C15-T50R	Fairchild Semiconductor	15 V	±5%	500 mW	30 Ω	1.5 V @ 100 mA	-65 to 200°C	DO-35	Active
BZX79C15	Taiwan Semiconductor Corporation	15 V	±5%	500 mW	30 Ω	1.5 V @ 100 mA	-65 to 175°C	DO-35	Active
BZX79-C15,113	Nexperia USA Inc.	15 V	±5%	400 mW	30 Ω	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
BZX79-C15,133	Nexperia USA Inc.	15 V	±5%	400 mW	30 Ω	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
BZX79-C15,143	Nexperia USA Inc.	15 V	±5%	400 mW	30 Ω	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
NZX15X,133	Nexperia USA Inc.	14.72 V	±2%	500 mW	40 Ω	1.5 V @ 200 mA	-55 to 175°C	ALF2	Active

Engineering Selection Recommendations

Recommended Direct Substitutes (Active Status, Full Compatibility):

The BZX79C15-T50A and BZX79C15-T50R from Fairchild Semiconductor are direct functional equivalents. Both parts maintain the 15 V nominal voltage, 500 mW power rating, and DO-35 package configuration. The ±5% tolerance represents improved specification control compared to the original ±6%. Both parts are in active production status with substantial inventory availability (45,200 and 35,677 units respectively). Operating temperature range extends to 200°C, matching the original specification.

The BZX79C15 from Taiwan Semiconductor Corporation is a parametric equivalent with identical electrical characteristics. This part is supplied in Tape & Reel packaging and carries RoHS3 compliance certification. The operating temperature range is -65°C to 175°C, which is 25°C lower than the original maximum. This part is suitable for applications not requiring operation above 175°C.

Alternative Substitutes (Active Status, Reduced Power Rating):

The BZX79-C15,113, BZX79-C15,133, and BZX79-C15,143 from Nexperia USA Inc. are functionally similar with 15 V nominal voltage and ±5% tolerance. These parts are rated at 400 mW maximum power, representing a 100 mW reduction from the original 500 mW specification. These parts are suitable for applications where power dissipation does not exceed 400 mW. All three variants are in active production with inventory availability ranging from 5,266 to 24,819 units. The ALF2 package is mechanically compatible with DO-35 applications. All parts carry RoHS3 compliance and ROHS3 certification.

Voltage-Adjacent Reference (Limited Compatibility):

The NZX15X,133 from Nexperia USA Inc. features a nominal voltage of 14.72 V with ±2% tolerance. This part falls within the tolerance band of the original BZX55C15 specification (15 V ±6% = 14.1 V to 15.9 V). The 500 mW power rating matches the original specification. However, the operating temperature range is -55°C to 175°C, which is narrower than the original -65°C to 200°C. This part is listed for reference only and requires circuit validation before implementation.

Frequently Asked Questions (FAQ)

Q: Can BZX79C15-T50A or BZX79C15-T50R be used as direct replacements for BZX55C15?

A: Yes. Both parts maintain the 15 V nominal voltage, 500 mW power rating, and DO-35 through-hole package. The ±5% tolerance is tighter than the original ±6%, ensuring improved voltage regulation accuracy. Both parts are in active production status.

Q: What is the difference between BZX79C15-T50A and BZX79C15-T50R?

A: Both parts are manufactured by Fairchild Semiconductor with identical electrical specifications. The designation suffix indicates different packaging or tape configurations. Both are suitable for direct substitution.

Q: Can I use BZX79-C15,113, BZX79-C15,133, or BZX79-C15,143 as replacements?

A: These parts are suitable only if your application does not require power dissipation exceeding 400 mW. The 15 V nominal voltage and ±5% tolerance match the original specification. The ALF2 package is mechanically compatible with DO-35 footprints. Verify that your circuit design does not exceed 400 mW power dissipation before implementation.

Q: What is the difference between the Nexperia BZX79-C15 variants (,113, ,133, ,143)?

A: All three variants share identical electrical specifications. The numeric suffixes indicate different packaging configurations or tape formats. Selection should be based on your procurement and assembly requirements.

Q: Is the BZX79C15 from Taiwan Semiconductor Corporation suitable for all applications?

A: The BZX79C15 is suitable for applications operating within -65°C to 175°C. If your application requires operation above 175°C, use the Fairchild BZX79C15-T50A or BZX79C15-T50R, which are rated to 200°C.

Q: Can I use NZX15X,133 as a replacement?

A: The NZX15X,133 has a nominal voltage of 14.72 V, which falls within the tolerance band of the original BZX55C15 (15 V ±6%). However, the operating temperature range is limited to -55°C to 175°C. Circuit validation is required before implementation, particularly if your application operates below -55°C or above 175°C.

Q: What compliance certifications should I verify for substitute parts?

A: All recommended substitute parts carry RoHS3 compliance and REACH Unaffected status, matching the original BZX55C15 specifications. ECCN classification is EAR99 for all parts listed.

Q: Does package type affect substitution compatibility?

A: The BZX55C15 uses DO-35 package. The Fairchild and Taiwan Semiconductor parts maintain DO-35 compatibility. The Nexperia parts use ALF2 package, which is mechanically compatible with DO-35 through-hole footprints. Verify PCB footprint compatibility before implementation.

Q: What inventory considerations should I account for?

A: The BZX55C15 is obsolete with 2,340 units in stock. Active substitute parts have significantly higher inventory: BZX79C15-T50A (45,200 units), BZX79C15-T50R (35,677 units), and BZX79C15 from Taiwan Semiconductor (4,600 units). Nexperia variants range from 5,266 to 24,819 units.

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