1N5940B-TP Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N5940B-TP is a 43 V, 1.5 W Zener diode manufactured by Micro Commercial Co in a DO-41G through-hole axial package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The part is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1) and operates across a temperature range of -55°C to 150°C.

Key Parameters

Parameter	Value
Voltage - Zener (Nom)	43 V
Power - Max	1.5 W
Tolerance	±5%
Impedance (Max)	53 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 32.7 V
Voltage - Forward (Max) @ If	1.2 V @ 200 mA
Operating Temperature	-55°C ~ 150°C
Package / Case	DO-204AL, DO-41, Axial
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the 1N5940B-TP is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 43 V nominal
Package type: DO-41 through-hole axial configuration
RoHS3 compliance requirement
Operating temperature range compatibility

Secondary Compatibility Factors:

Power dissipation rating (1.5 W nominal; 1.3 W acceptable for lower-power applications)
Voltage tolerance (±5% or tighter)
Impedance characteristics (50-53 Ohms maximum)
Reverse leakage current specifications

Substitute parts are grouped into two categories based on power rating and manufacturer:

Category 1: Same Manufacturer (Micro Commercial Co)

1N5940BP-TP: Active product status, identical electrical specifications, extended operating temperature to 175°C, tape & reel packaging

Category 2: Alternative Manufacturer (Vishay General Semiconductor)

BZX85B43-TR, BZX85B43-TAP: ±2% tolerance, 1.3 W power rating, automotive grade with AEC-Q101 qualification
BZX85C43-TR, BZX85C43-TAP: ±5% tolerance, 1.3 W power rating, automotive grade with AEC-Q101 qualification
ZPY43-TR, ZPY43-TAP: ±5% tolerance, 1.3 W power rating, automotive grade with AEC-Q101 qualification, lower impedance (35 Ohms)

All substitute parts maintain the DO-41 package configuration and ROHS3 compliance.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Power (Max)	Tolerance	Zzt (Max)	Reverse Leakage @ Vr	Operating Temp	Status	Package
1N5940B-TP	Micro Commercial Co	43 V	1.5 W	±5%	53 Ohms	1 µA @ 32.7 V	-55°C ~ 150°C	Obsolete	DO-41G
1N5940BP-TP	Micro Commercial Co	43 V	1.5 W	±5%	53 Ohms	1 µA @ 32.7 V	-55°C ~ 175°C	Active	DO-41
BZX85B43-TR	Vishay	43 V	1.3 W	±2%	50 Ohms	500 nA @ 33 V	-55°C ~ 175°C	Active	DO-41
BZX85B43-TAP	Vishay	43 V	1.3 W	±2%	50 Ohms	500 nA @ 33 V	-55°C ~ 175°C	Active	DO-41
BZX85C43-TR	Vishay	43 V	1.3 W	±5%	50 Ohms	500 nA @ 33 V	-55°C ~ 175°C	Active	DO-41
BZX85C43-TAP	Vishay	43 V	1.3 W	±5%	50 Ohms	500 nA @ 33 V	-55°C ~ 175°C	Active	DO-41
ZPY43-TR	Vishay	43 V	1.3 W	±5%	35 Ohms	500 nA @ 32 V	-55°C ~ 175°C	Active	DO-41
ZPY43-TAP	Vishay	43 V	1.3 W	±5%	35 Ohms	500 nA @ 32 V	-55°C ~ 175°C	Active	DO-41

Engineering Selection Recommendations

Primary Recommendation: 1N5940BP-TP

The 1N5940BP-TP is the direct equivalent from the same manufacturer (Micro Commercial Co). It maintains identical electrical specifications to the 1N5940B-TP while offering active product status. The extended operating temperature range (-55°C to 175°C) provides additional thermal margin. This part is suitable for direct replacement in existing designs without circuit modification.

Secondary Recommendations: Vishay BZX85 and ZPY Series

The Vishay BZX85B43 and BZX85C43 series provide active, automotive-qualified alternatives with AEC-Q101 certification. The BZX85B43 variant offers tighter tolerance (±2%) compared to the original ±5% specification. The BZX85C43 variant maintains ±5% tolerance matching the original part. Both series feature lower reverse leakage current (500 nA versus 1 µA) and comparable impedance (50 Ohms versus 53 Ohms).

The Vishay ZPY43 series offers the lowest impedance (35 Ohms) among available substitutes, providing superior high-frequency performance characteristics. This series is also automotive-qualified with AEC-Q101 certification.

Packaging Considerations:

Cut Tape (CT) packaging: BZX85B43-TR, BZX85C43-TR, ZPY43-TR (highest inventory availability)
Tape & Box (TB) packaging: BZX85B43-TAP, BZX85C43-TAP, ZPY43-TAP
Tape & Reel (TR) packaging: 1N5940BP-TP

Power Rating Consideration:

The 1N5940B-TP is rated at 1.5 W maximum power dissipation. All Vishay substitutes are rated at 1.3 W. In applications where the circuit operates below 1.3 W, Vishay parts are fully compatible. Applications requiring the full 1.5 W rating should use the 1N5940BP-TP.

Frequently Asked Questions (FAQ)

Q: Can I use a BZX85C43-TR in place of the 1N5940B-TP?

A: Yes. Both parts share the same 43 V nominal zener voltage, ±5% tolerance, DO-41 package configuration, and ROHS3 compliance. The BZX85C43-TR operates at 1.3 W maximum power versus 1.5 W for the original part. If your circuit dissipates 1.3 W or less, this substitution is valid. The BZX85C43-TR offers superior reverse leakage characteristics (500 nA versus 1 µA) and automotive qualification.

Q: What is the difference between BZX85B43 and BZX85C43?

A: The primary difference is voltage tolerance. BZX85B43 offers ±2% tolerance, while BZX85C43 offers ±5% tolerance. Both share identical power ratings (1.3 W), impedance (50 Ohms), operating temperature range (-55°C to 175°C), and package configuration. Select BZX85B43 for applications requiring tighter voltage regulation; select BZX85C43 for applications matching the original ±5% specification.

Q: Why do ZPY43 parts have lower impedance than other substitutes?

A: The ZPY43 series is designed with 35 Ohms maximum impedance compared to 50-53 Ohms in other 43 V zener diodes. Lower impedance provides better voltage regulation at higher currents and improved transient response. This characteristic makes ZPY43 parts suitable for applications requiring superior dynamic performance.

Q: Are all substitute parts automotive-qualified?

A: The 1N5940BP-TP (Micro Commercial Co) does not carry automotive qualification. All Vishay substitutes (BZX85B43, BZX85C43, ZPY43 series) are automotive-grade with AEC-Q101 qualification. Select Vishay parts for automotive applications.

Q: What packaging format should I choose?

A: Cut Tape (CT) packaging is standard for high-volume procurement and offers the largest inventory availability. Tape & Box (TB) packaging is suitable for moderate-volume orders. Tape & Reel (TR) packaging is used for automated assembly processes. All three formats are electrically equivalent; selection depends on procurement and assembly requirements.

Q: Can I substitute a 1.3 W part for a 1.5 W part?

A: Substitution is valid only if your circuit design operates below 1.3 W maximum power dissipation. Review your circuit's power budget to confirm the zener diode dissipates 1.3 W or less under all operating conditions, including worst-case scenarios. If your design requires the full 1.5 W capability, use the 1N5940BP-TP.

Q: Is the 1N5940BP-TP a direct replacement for the 1N5940B-TP?

A: Yes. The 1N5940BP-TP is the direct active equivalent from the same manufacturer. It maintains all electrical specifications and package configuration. The extended operating temperature range (175°C versus 150°C) provides additional thermal margin without affecting circuit compatibility.

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