BZX85C43 Equivalent & Substitute Parts

Part Overview

The BZX85C43 is a 43 V, 1 W Zener diode manufactured by onsemi in DO-41 axial through-hole packaging. This component is classified as obsolete, indicating discontinued production and limited availability. The BZX85C43 serves voltage regulation and protection applications requiring precise 43 V reference voltage with ±7% tolerance. Due to obsolete status, equivalent substitute parts with active production status are necessary for new designs and ongoing procurement requirements.

Key Parameters

Parameter	Value
Voltage - Zener (Nom) (Vz)	43 V
Tolerance	±7%
Power - Max	1 W
Impedance (Max) (Zzt)	50 Ohms
Current - Reverse Leakage @ Vr	500 nA @ 30 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

Substitute Part Grouping Explanation

Substitution of the BZX85C43 is determined by the following critical parameters: nominal Zener voltage (43 V), power dissipation rating, tolerance specification, impedance characteristics, and through-hole axial package compatibility. All substitute parts listed maintain the 43 V nominal Zener voltage and through-hole mounting configuration. Substitutes are grouped by power rating capability, as this parameter directly affects circuit performance in voltage regulation and transient protection applications. Tolerance, impedance, and reverse leakage specifications vary among substitutes and must be evaluated against circuit requirements. Operating temperature range and forward voltage characteristics are secondary selection criteria based on application environment and load conditions.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power - Max	Zzt (Max)	Vf (Max) @ If	Operating Temp	Product Status
BZX85C43	onsemi	43 V	±7%	1 W	50 Ohms	1.2 V @ 200 mA	-65°C ~ 200°C	Obsolete
1N4755A	Lumimax Optoelectronic Technology	43 V	±5%	1 W	70 Ohms	1.2 V @ 200 mA	-65°C ~ 200°C	Active
1N5940BP-TP	Micro Commercial Co	43 V	±5%	1.5 W	53 Ohms	1.5 V @ 200 mA	-55°C ~ 175°C	Active
2EZ43D5-TP	Micro Commercial Co	43 V	±5%	2 W	35 Ohms	1.2 V @ 200 mA	-55°C ~ 150°C	Active
2EZ43D5	Microsemi Corporation	43 V	±5%	2 W	35 Ohms	1.2 V @ 200 mA	-65°C ~ 150°C	Active
1N5367B	Microsemi Corporation	43 V	±5%	5 W	20 Ohms	1.2 V @ 1 A	-65°C ~ 150°C	Active
1N5940B3P-TP	Micro Commercial Co	43 V	±5%	3 W	53 Ohms	1.5 V @ 200 mA	-55°C ~ 175°C	Active

Engineering Selection Recommendations

Direct 1:1 Substitution (Equivalent Power Rating)

The 1N4755A provides the closest electrical equivalence to the BZX85C43, maintaining identical 1 W power rating and operating temperature range of -65°C to 200°C. The 1N4755A features improved tolerance specification (±5% versus ±7%) and active product status. This part is suitable for direct replacement in existing designs without circuit modification.

Higher Power Rating Substitutes (Upgraded Capability)

The 1N5940BP-TP (1.5 W), 2EZ43D5-TP (2 W), 2EZ43D5 (2 W), 1N5940B3P-TP (3 W), and 1N5367B (5 W) provide increased power dissipation capability while maintaining 43 V nominal Zener voltage. These parts are suitable for applications requiring enhanced transient protection or higher current handling. All listed substitutes maintain active product status and REACH compliance. The 1N5367B offers the highest power rating (5 W) with lowest impedance (20 Ohms), providing superior voltage regulation stability in high-current applications.

Compliance and Availability Considerations

All substitute parts maintain REACH Unaffected status. The 1N4755A and 1N5940BP-TP are RoHS compliant. The 2EZ43D5 and 1N5367B are RoHS non-compliant. Inventory availability varies significantly, with 2EZ43D5 offering the highest stock level (36,850 pcs) and 2EZ43D5-TP the lowest (935 pcs).

Temperature Range Limitations

The BZX85C43 operates to 200°C maximum junction temperature. Substitute parts 1N5940BP-TP, 1N5940B3P-TP, and 2EZ43D5-TP are limited to 175°C maximum. The 2EZ43D5 and 1N5367B are limited to 150°C maximum. Applications requiring operation above 150°C require the 1N4755A or 2EZ43D5 (Microsemi version) with -65°C to 150°C range.

Frequently Asked Questions (FAQ)

Q: Can the 1N4755A directly replace the BZX85C43 without circuit modification?

A: Yes. The 1N4755A maintains identical 43 V nominal voltage, 1 W power rating, and -65°C to 200°C operating temperature range. The improved ±5% tolerance provides tighter voltage regulation compared to the original ±7% specification. No circuit changes are required.

Q: What is the difference between 2EZ43D5 and 2EZ43D5-TP?

A: Both parts are 43 V, 2 W Zener diodes with identical electrical specifications. The primary difference is manufacturer: 2EZ43D5 is manufactured by Microsemi Corporation with -65°C to 150°C operating range, while 2EZ43D5-TP is manufactured by Micro Commercial Co with -55°C to 150°C operating range. The Microsemi version supports lower minimum operating temperature.

Q: Why would I select a higher power rating substitute like the 1N5367B?

A: Higher power rating substitutes provide increased thermal margin and improved voltage regulation stability in circuits with variable load conditions or transient current spikes. The 1N5367B (5 W) with 20 Ohms impedance offers superior dynamic response compared to the 1 W original specification. Selection depends on circuit requirements for transient protection and thermal dissipation capability.

Q: Are all substitute parts available in DO-41 axial through-hole packaging?

A: Yes. All listed substitute parts are specified for through-hole mounting in DO-41 or DO-204AL axial package configurations, maintaining mechanical compatibility with the BZX85C43 footprint.

Q: What is the significance of impedance (Zzt) differences among substitutes?

A: Impedance affects voltage regulation quality under dynamic load conditions. Lower impedance values (1N5367B at 20 Ohms) provide better voltage stability and faster transient response. Higher impedance values (1N4755A at 70 Ohms) result in slightly softer voltage regulation. Circuit design determines whether impedance differences are significant.

Q: Can I use the 1N5940BP-TP in applications originally designed for the BZX85C43?

A: Yes, with consideration of operating temperature limits. The 1N5940BP-TP provides 1.5 W power rating (50% higher than original) and maintains 43 V nominal voltage. However, maximum operating temperature is limited to 175°C compared to the BZX85C43 specification of 200°C. Applications operating above 175°C require alternative selection.

Q: What RoHS compliance status should I specify for new designs?

A: For RoHS-compliant applications, select 1N4755A or 1N5940BP-TP. The 2EZ43D5, 2EZ43D5-TP, and 1N5367B are RoHS non-compliant and unsuitable for regulated markets requiring RoHS certification.

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