BZX79C39 Equivalent & Substitute Parts

Part Overview

The BZX79C39 is a Zener diode rated at 39 V nominal voltage with 500 mW maximum power dissipation in a DO-35 through-hole axial package. Manufactured by onsemi, this component is classified as obsolete, though 5200 pieces remain in stock as new original inventory. The obsolete status necessitates identification of active equivalent and substitute parts to ensure design continuity and long-term component availability for new production and maintenance applications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	39	V
Tolerance	±5%	—
Power - Max	500	mW
Impedance (Max)	130	Ohms
Current - Reverse Leakage @ Vr	50 nA @ 27.3 V	—
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 100 mA	—
Operating Temperature Range	-65 to 200	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—

Substitute Part Grouping Explanation

Substitution of the BZX79C39 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 39 V (exact match required)
Tolerance: ±5% or tighter (±1%, ±2% acceptable; ±10% acceptable with design review)
Power - Max: 500 mW or greater
Impedance (Max): 130 Ohms or lower
Operating Temperature Range: -65°C minimum and 200°C maximum (or equivalent minimum range)
Mounting Type: Through Hole
Package / Case: DO-35 or equivalent axial configuration

Substitute Categories:

Direct Electrical Equivalents (500 mW, DO-35 Package): Parts matching all primary criteria with identical power rating and package form factor. These include 1N5750B, 1N5750C, 1N5750D, 1N6014A, 1N6014C, and 1N6014D.
Nexperia BZX79-C39 Series (400 mW, ALF2 Package): Parts BZX79-C39,113, BZX79-C39,133, and BZX79-C39,143 provide equivalent electrical performance with slightly reduced power rating (400 mW) and alternative through-hole package configuration. These are suitable where power dissipation does not exceed 400 mW.
Higher Power Alternative (5 W, Axial Package): Part 1N5366BRLG provides significantly increased power handling (5 W) in an axial through-hole configuration, suitable for applications requiring higher power dissipation at 39 V nominal voltage.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Vr Leakage	Vf (Max)	Temp Range	Package	Status
BZX79C39	onsemi	39 V	±5%	500 mW	130 Ω	50 nA @ 27.3 V	1.5 V @ 100 mA	-65 to 200°C	DO-35	Obsolete
BZX79-C39,113	Nexperia USA Inc.	39 V	±5%	400 mW	130 Ω	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
BZX79-C39,133	NXP USA Inc.	39 V	±5%	400 mW	130 Ω	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
BZX79-C39,143	NXP Semiconductors	39 V	±5%	400 mW	130 Ω	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 200°C	ALF2	Active
1N5366BRLG	onsemi	39 V	±5%	5 W	14 Ω	500 nA @ 29.7 V	1.2 V @ 1 A	-65 to 200°C	Axial	Active
1N5750B	Microchip Technology	39 V	±5%	500 mW	130 Ω	100 nA @ 27 V	900 mV @ 10 mA	-65 to 175°C	DO-35	Active
1N5750C	Microchip Technology	39 V	±1%	500 mW	130 Ω	100 nA @ 27 V	900 mV @ 10 mA	-65 to 175°C	DO-35	Active
1N5750D	Microchip Technology	39 V	±1%	500 mW	130 Ω	100 nA @ 27 V	900 mV @ 10 mA	-65 to 175°C	DO-35	Active
1N6014A	Microchip Technology	39 V	±10%	500 mW	170 Ω	100 nA @ 25 V	1.1 V @ 200 mA	-65 to 175°C	DO-35	Active
1N6014C	Microchip Technology	39 V	±2%	500 mW	130 Ω	100 nA @ 30 V	1.1 V @ 200 mA	-65 to 175°C	DO-35	Active
1N6014D	Microchip Technology	39 V	±1%	500 mW	130 Ω	100 nA @ 30 V	1.1 V @ 200 mA	-65 to 175°C	DO-35	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical and Mechanical Performance):

The 1N5750C and 1N6014D are preferred direct replacements for the BZX79C39. Both parts are manufactured by Microchip Technology, are in active product status, and provide 39 V nominal voltage with 500 mW power rating in DO-35 through-hole axial packages. The 1N5750C offers ±1% tolerance compared to the original ±5%, providing tighter voltage regulation. The 1N6014D similarly provides ±1% tolerance with equivalent electrical specifications. Both parts maintain the -65°C to 175°C operating temperature range, which encompasses the original -65°C to 200°C specification for the majority of industrial applications.

For Applications with Reduced Power Dissipation (≤400 mW):

The Nexperia BZX79-C39 series (BZX79-C39,113, BZX79-C39,133, BZX79-C39,143) provides active alternatives with 400 mW maximum power rating. These parts maintain identical 39 V nominal voltage, ±5% tolerance, and 130 Ohm maximum impedance. The BZX79-C39,113 and BZX79-C39,133 are in active status with high inventory availability (925 and 264,753 pieces respectively). The ALF2 package configuration is mechanically compatible with through-hole PCB designs. These parts are suitable for designs where power dissipation does not exceed 400 mW.

For Applications Requiring Higher Power Dissipation:

The 1N5366BRLG, manufactured by onsemi, provides 5 W maximum power dissipation at 39 V nominal voltage in an axial through-hole package. This part is in active status and maintains the -65°C to 200°C operating temperature range matching the original specification. The 1N5366BRLG is suitable for applications requiring significantly higher power handling capability while maintaining the same nominal voltage regulation.

Compliance and Regulatory Status:

All recommended substitute parts carry REACH Unaffected status and EAR99 ECCN classification, matching the regulatory profile of the original BZX79C39. The Nexperia BZX79-C39 series and 1N5366BRLG carry RoHS3 compliance certification. Microchip Technology parts (1N5750 and 1N6014 series) are RoHS non-compliant; design teams requiring RoHS compliance should select Nexperia or onsemi alternatives.

Frequently Asked Questions (FAQ)

Q: Can the 1N5750B be used as a direct replacement for the BZX79C39?

A: The 1N5750B is electrically and mechanically compatible with the BZX79C39. Both parts provide 39 V nominal voltage, ±5% tolerance, 500 mW power rating, and DO-35 through-hole axial packaging. The primary difference is the operating temperature range: 1N5750B operates from -65°C to 175°C compared to the original -65°C to 200°C. For applications operating below 175°C, the 1N5750B is a suitable direct replacement.

Q: What is the difference between the BZX79-C39,113, BZX79-C39,133, and BZX79-C39,143?

A: These three parts are electrically identical, all providing 39 V nominal voltage, ±5% tolerance, 400 mW power rating, and 130 Ohm maximum impedance. The differences are manufacturer designation (Nexperia USA Inc., NXP USA Inc., and NXP Semiconductors respectively) and packaging format (Cut Tape and Bulk). All three are in active status. Selection between these parts is based on packaging preference and inventory availability.

Q: Why does the 1N6014A have a ±10% tolerance when the original BZX79C39 specifies ±5%?

A: The 1N6014A is a lower-tolerance variant within the 1N6014 family. While it maintains the same 39 V nominal voltage and 500 mW power rating, the ±10% tolerance specification indicates a wider acceptable voltage range (35.1 V to 42.9 V). This part is suitable for applications where voltage regulation tolerance is not critical. For applications requiring tighter voltage control, the 1N6014C (±2%) or 1N6014D (±1%) are preferred.

Q: Is the 1N5366BRLG suitable for all applications using the BZX79C39?

A: The 1N5366BRLG is electrically compatible (39 V nominal voltage, ±5% tolerance) but differs significantly in power rating (5 W versus 500 mW) and impedance (14 Ohms versus 130 Ohms). The lower impedance of the 1N5366BRLG results in different voltage regulation characteristics under load. This part is suitable for applications requiring higher power dissipation or where the lower impedance characteristic is beneficial. For direct replacement in existing designs, lower-power alternatives are more appropriate.

Q: What is the significance of the impedance (Zzt) parameter in selecting a substitute?

A: Impedance (Zzt) determines the dynamic voltage regulation of the Zener diode under changing load conditions. The BZX79C39 specifies 130 Ohm maximum impedance. Substitute parts with equal or lower impedance (such as 1N5750B, 1N5750C, 1N5750D, 1N6014C, and 1N6014D at 130 Ohms) provide equivalent or superior voltage regulation. The 1N6014A with 170 Ohm impedance exhibits slightly higher dynamic voltage variation. The 1N5366BRLG with 14 Ohm impedance provides significantly tighter voltage regulation but is intended for higher-power applications.

Q: Are there any RoHS compliance considerations when selecting a substitute?

A: The original BZX79C39 does not carry RoHS compliance certification. The Nexperia BZX79-C39 series (BZX79-C39,113, BZX79-C39,133, BZX79-C39,143) and 1N5366BRLG carry RoHS3 compliance. The Microchip Technology 1N5750 and 1N6014 series are RoHS non-compliant. For designs requiring RoHS compliance, select from the Nexperia or onsemi alternatives.

Q: Can the BZX79-C39,113 be used in place of the BZX79C39 if power dissipation is limited to 400 mW?

A: Yes. The BZX79-C39,113 provides identical electrical specifications (39 V nominal, ±5% tolerance, 130 Ohm impedance) and maintains the full -65°C to 200°C operating temperature range. The 400 mW power rating is sufficient for applications where actual power dissipation does not exceed this level. The ALF2 package is mechanically compatible with through-hole PCB designs. This part is in active status with good inventory availability.

Q: What is the difference between DO-35 and ALF2 packages?

A: Both DO-35 and ALF2 are through-hole axial package configurations suitable for PCB mounting. The primary difference is the physical form factor and lead configuration. DO-35 is the standard package for the original BZX79C39 and is used by Microchip Technology (1N5750 and 1N6014 series). ALF2 is the package designation used by Nexperia for the BZX79-C39 series. Both are compatible with standard through-hole PCB designs; selection depends on PCB layout requirements and component availability.

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