BZX85C39 Equivalent & Substitute Parts

Part Overview

The BZX85C39 is a 39 V, 1 W Zener diode manufactured by onsemi in DO-41 through-hole packaging. This component is classified as obsolete, indicating discontinued production and limited availability. The BZX85C39 serves voltage regulation and protection applications requiring a nominal Zener voltage of 39 V with ±5% tolerance and 1 W maximum power dissipation. Due to obsolete status, equivalent substitute parts with matching or enhanced electrical characteristics are necessary for design continuity and procurement reliability.

Key Parameters

Parameter	BZX85C39 Value
Voltage - Zener (Nom) (Vz)	39 V
Tolerance	±5%
Power - Max	1 W
Impedance (Max) (Zzt)	45 Ohms
Current - Reverse Leakage @ Vr	500 nA @ 27 V
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 200 mA
Operating Temperature	-65°C ~ 200°C
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the BZX85C39 are selected based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Critical Matching Parameters:

Voltage - Zener (Nom) (Vz): 39 V (all substitutes maintain this specification)
Tolerance: ±5% (all substitutes maintain this specification)
Mounting Type: Through Hole (all substitutes maintain this specification)
Package / Case: DO-41 or DO-204AL (all substitutes maintain axial through-hole configuration)

Allowable Variation Parameters:

Power - Max: Substitutes with equal or greater power rating (1 W, 1.5 W, 2 W, or 3 W) are acceptable
Impedance (Max) (Zzt): Substitutes with equal or lower impedance are acceptable
Current - Reverse Leakage @ Vr: Substitutes with equal or lower leakage current are acceptable
Voltage - Forward (Vf) (Max) @ If: Substitutes with equal or lower forward voltage are acceptable
Operating Temperature: Substitutes with equal or wider temperature range are acceptable
Product Status: Active status substitutes provide superior procurement availability

Substitutes are grouped into two categories: direct equivalents (matching 1 W power rating) and enhanced alternatives (higher power ratings for increased thermal margin).

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power - Max	Zzt (Max)	Reverse Leakage @ Vr	Vf (Max) @ If	Operating Temp	Product Status
BZX85C39	onsemi	39 V	±5%	1 W	45 Ohms	500 nA @ 27 V	1.2 V @ 200 mA	-65°C ~ 200°C	Obsolete
1N4754A	Lumimax Optoelectronic Technology	39 V	±5%	1 W	60 Ohms	5 µA @ 29.7 V	1.2 V @ 200 mA	-65°C ~ 200°C	Active
1EZ39D5-TP	Micro Commercial Co	39 V	±5%	1 W	60 Ohms	5 µA @ 29.7 V	1.2 V @ 200 mA	-55°C ~ 150°C	Active
1N5939BP-TP	Micro Commercial Co	39 V	±5%	1.5 W	45 Ohms	1 µA @ 29.7 V	1.5 V @ 200 mA	-55°C ~ 175°C	Active
1N5939B3P-TP	Micro Commercial Co	39 V	±5%	3 W	45 Ohms	1 µA @ 29.7 V	1.5 V @ 200 mA	-55°C ~ 175°C	Active
2EZ39D5-TP	Micro Commercial Co	39 V	±5%	2 W	30 Ohms	500 nA @ 29.7 V	1.2 V @ 200 mA	-55°C ~ 150°C	Active
2EZ39D5-AP	Micro Commercial Co	39 V	±5%	2 W	30 Ohms	500 nA @ 29.7 V	1.2 V @ 200 mA	-55°C ~ 150°C	Active
2EZ39D5	Microsemi Corporation	39 V	±5%	2 W	30 Ohms	500 nA @ 29.7 V	1.2 V @ 200 mA	-65°C ~ 150°C	Active

Engineering Selection Recommendations

Direct Equivalent (1 W Power Rating):

The 1N4754A manufactured by Lumimax Optoelectronic Technology provides the closest functional equivalent to the BZX85C39. Both components share identical Zener voltage (39 V), tolerance (±5%), power rating (1 W), and forward voltage characteristics (1.2 V @ 200 mA). The 1N4754A maintains the full operating temperature range of the original part (-65°C ~ 200°C) and is currently in active production status, ensuring reliable procurement. This part is suitable for direct replacement in applications where the original BZX85C39 specifications are required.

The 1EZ39D5-TP from Micro Commercial Co also provides 1 W equivalent performance with matching Zener voltage and tolerance. However, this part operates within a narrower temperature range (-55°C ~ 150°C) compared to the BZX85C39. Selection of this part is appropriate only when the application operating temperature remains within the specified limits.

Enhanced Alternatives (Higher Power Ratings):

The 2EZ39D5-TP and 2EZ39D5-AP from Micro Commercial Co provide 2 W power dissipation capability, offering increased thermal margin over the original 1 W specification. Both parts maintain the 39 V Zener voltage and ±5% tolerance. The 2EZ39D5-TP is supplied in Tape & Reel packaging with RoHS3 compliance, while 2EZ39D5-AP is supplied in bulk packaging. These parts feature improved impedance characteristics (30 Ohms maximum versus 45 Ohms) and are suitable for applications requiring enhanced power handling.

The 2EZ39D5 from Microsemi Corporation provides identical 2 W performance with the extended operating temperature range (-65°C ~ 150°C), matching the lower temperature limit of the original BZX85C39.

The 1N5939BP-TP and 1N5939B3P-TP from Micro Commercial Co provide 1.5 W and 3 W power ratings respectively, offering progressively higher thermal capability. Both maintain the 39 V Zener voltage specification and feature impedance matching the original part (45 Ohms). These parts are suitable for applications requiring significant power dissipation margin.

Compliance Considerations:

The 2EZ39D5-TP carries RoHS3 compliance certification, suitable for applications with regulatory requirements. The 1N5939BP-TP also carries RoHS3 compliance. All substitute parts maintain REACH Unaffected status and EAR99 export classification consistent with the original BZX85C39.

Frequently Asked Questions (FAQ)

Q: Can the 1N4754A directly replace the BZX85C39 in all applications?

A: Yes. The 1N4754A matches all critical electrical parameters of the BZX85C39: 39 V Zener voltage, ±5% tolerance, 1 W power rating, and 1.2 V forward voltage at 200 mA. Both components operate across the identical temperature range (-65°C ~ 200°C) and use DO-41 through-hole packaging. The 1N4754A is suitable for direct substitution.

Q: What is the advantage of using a 2 W substitute instead of a 1 W equivalent?

A: A 2 W substitute such as 2EZ39D5-TP provides increased thermal margin and lower impedance (30 Ohms versus 45 Ohms). Higher power rating allows the component to dissipate greater heat without exceeding maximum junction temperature, extending component life in applications with sustained current flow. Lower impedance improves voltage regulation stability.

Q: Are there packaging differences between substitute parts?

A: All substitute parts use DO-41 through-hole axial packaging, maintaining mechanical compatibility with the original BZX85C39. Packaging format differences exist only in supplier delivery method: some parts are supplied in Tape & Reel (TR) format for automated assembly, while others are supplied in bulk. The physical component package remains identical.

Q: Does the 1EZ39D5-TP have any limitations compared to the BZX85C39?

A: The 1EZ39D5-TP operates within a narrower temperature range (-55°C ~ 150°C) compared to the BZX85C39 (-65°C ~ 200°C). This part is suitable only for applications where the operating temperature remains within the specified limits. For applications requiring the full temperature range of the original part, use 1N4754A or 2EZ39D5 instead.

Q: Which substitute offers the best compliance certifications?

A: The 2EZ39D5-TP carries RoHS3 compliance certification and is supplied in Tape & Reel packaging suitable for automated assembly. The 1N5939BP-TP also carries RoHS3 compliance. All substitute parts maintain REACH Unaffected status. Selection based on compliance requirements depends on specific regulatory obligations of the application.

Q: Can a 3 W substitute be used in place of the 1 W original?

A: Yes. The 1N5939B3P-TP provides 3 W power rating while maintaining the 39 V Zener voltage and ±5% tolerance. Higher power rating is backward compatible with applications designed for lower power dissipation. The 3 W part provides maximum thermal margin and is suitable for applications with uncertain or variable current conditions.

Q: What is the difference between 2EZ39D5-TP and 2EZ39D5-AP?

A: Both parts provide identical electrical specifications: 39 V Zener voltage, ±5% tolerance, 2 W power rating, and 30 Ohms maximum impedance. The primary difference is packaging format: 2EZ39D5-TP is supplied in Tape & Reel (TR) format with RoHS3 compliance, while 2EZ39D5-AP is supplied in bulk format. Selection depends on assembly method and regulatory requirements.

Q: Is the reverse leakage current difference between substitutes significant?

A: Reverse leakage current varies among substitutes from 500 nA to 5 µA at specified voltage conditions. Lower leakage current (500 nA) is present in 2EZ39D5 series parts and the original BZX85C39, while higher leakage (5 µA) is present in 1N4754A and 1EZ39D5-TP. For most voltage regulation applications, both levels are acceptable. Applications requiring minimal standby current should prioritize parts with 500 nA leakage specification.

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