1N4755A-T Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N4755A-T is a 43 V, 1 W zener diode manufactured by Diodes Incorporated in DO-41 through-hole package. This part is classified as obsolete, necessitating identification of active equivalent and substitute components for ongoing design requirements and production continuity. The 1N4755A-T operates across a temperature range of -65°C to 175°C with ±5% voltage tolerance and is ROHS3 compliant. Substitute parts are selected based on matching or exceeding electrical specifications while maintaining mechanical compatibility.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	43	V
Tolerance	±5%	—
Power - Maximum	1	W
Impedance (Maximum)	70	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 32.7 V
Voltage - Forward (Maximum) @ If	1.2	V @ 200 mA
Operating Temperature Range	-65 to 175	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AL, DO-41, Axial	—

Substitute Part Grouping Explanation

Substitution of the 1N4755A-T is determined by the following critical parameters:

Electrical Matching Criteria:

Zener voltage: 43 V nominal
Voltage tolerance: ±5% or tighter
Power dissipation: minimum 1 W (equal or greater)
Impedance: 70 Ohms maximum
Reverse leakage current: 5 µA @ 32.7 V maximum
Forward voltage: 1.2 V @ 200 mA maximum

Mechanical Compatibility:

Mounting type: Through Hole
Package: DO-204AL, DO-41, or Axial equivalent
Lead configuration: Axial leads

Compliance & Status:

Product status: Active preferred (obsolete part requires active replacement)
RoHS compliance: ROHS3 compliant preferred
Operating temperature: -65°C minimum, 175°C minimum

Substitute parts are grouped into three categories: direct equivalents (matching all specifications), upgrades (enhanced power or temperature ratings), and functional alternatives (meeting core electrical requirements with acceptable parameter variations).

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (W)	Zzt (Ohms)	Ir @ Vr (µA)	Vf @ If (V)	Temp Range (°C)	Status	RoHS
1N4755A-T	Diodes Incorporated	43	±5%	1	70	5 @ 32.7	1.2 @ 200	-65 to 175	Obsolete	ROHS3
1N4755A	Lumimax Optoelectronic Technology	43	±5%	1	70	5 @ 32.7	1.2 @ 200	-65 to 200	Active	RoHS
1N4755AP/TR8	Microchip Technology	43	±5%	1	70	5 @ 32.7	1.2 @ 200	-65 to 150	Active	Non-compliant
1N4755A-T50A	Fairchild Semiconductor	43	±5%	1	70	5 @ 32.7	—	-65 to 200	Active	—
1N4755 G	Microsemi Corporation	43	±10%	1	70	5 @ 32.7	1.2 @ 200	-65 to 175	Active	Non-compliant
1N4755A-TAP	Vishay General Semiconductor - Diodes Division	43	±5%	1.3	70	5 @ 32.7	1.2 @ 200	-65 to 175	Active	ROHS3
1N4755A-TR	Vishay General Semiconductor - Diodes Division	43	±5%	1.3	70	5 @ 32.7	1.2 @ 200	-65 to 175	Active	ROHS3
1N5940BP-TP	Micro Commercial Co	43	±5%	1.5	53	1 @ 32.7	1.5 @ 200	-55 to 175	Active	ROHS3
2EZ43D5	Microsemi Corporation	43	±5%	2	35	0.5 @ 32.7	1.2 @ 200	-65 to 150	Active	Non-compliant
2EZ43D5-TP	Micro Commercial Co	43	±5%	2	35	0.5 @ 32.7	1.2 @ 200	-55 to 150	Active	—

Engineering Selection Recommendations

Direct Equivalents (Preferred for Drop-In Replacement):

The 1N4755A manufactured by Lumimax Optoelectronic Technology provides the closest electrical and mechanical match to the obsolete 1N4755A-T. This part maintains identical zener voltage (43 V), tolerance (±5%), power rating (1 W), and impedance (70 Ohms). The Lumimax part extends the operating temperature range to 200°C and carries active product status with RoHS compliance, making it suitable for direct substitution in new designs and production continuity.

Upgraded Alternatives (Enhanced Performance):

The 1N4755A-TAP and 1N4755A-TR from Vishay General Semiconductor - Diodes Division offer increased power dissipation (1.3 W) while maintaining all other electrical parameters. Both parts are ROHS3 compliant, active, and qualified to AEC-Q101 automotive standards. These parts provide thermal margin above the original 1 W specification and are suitable for applications requiring enhanced reliability or thermal headroom.

The 1N5940BP-TP from Micro Commercial Co provides 1.5 W power dissipation with improved impedance characteristics (53 Ohms versus 70 Ohms) and reduced reverse leakage current (1 µA versus 5 µA). This part is ROHS3 compliant and active, offering superior performance for demanding applications.

The 2EZ43D5 and 2EZ43D5-TP from Microsemi Corporation and Micro Commercial Co respectively provide 2 W power dissipation with significantly reduced impedance (35 Ohms) and reverse leakage current (500 nA). These parts are active and suitable for high-reliability applications requiring enhanced thermal performance.

Conditional Alternatives:

The 1N4755AP/TR8 from Microchip Technology and 1N4755 G from Microsemi Corporation maintain electrical equivalence but carry RoHS non-compliance status. These parts are active and suitable only for applications where RoHS compliance is not required.

Packaging Considerations:

The 1N4755A-TAP is supplied in Tape & Box (TB) packaging, the 1N4755A-TR in Cut Tape (CT) packaging, and the 1N5940BP-TP in Tape & Reel (TR) packaging. The 1N4755A-T50A is supplied in bulk. Packaging selection depends on production volume and assembly process requirements.

Frequently Asked Questions (FAQ)

Q: Can the 1N4755A from Lumimax be used as a direct replacement for the 1N4755A-T?

A: Yes. The Lumimax 1N4755A provides identical electrical specifications (43 V, ±5%, 1 W, 70 Ohms impedance) and mechanical compatibility (DO-41 through-hole package). The extended temperature range (-65°C to 200°C) and active product status make it suitable for direct substitution.

Q: What is the difference between the 1N4755A-TAP and 1N4755A-TR?

A: Both parts are manufactured by Vishay and provide identical electrical specifications. The primary difference is packaging: 1N4755A-TAP is supplied in Tape & Box (TB) format, while 1N4755A-TR is supplied in Cut Tape (CT) format. Electrical performance and reliability are equivalent.

Q: Why would I select the 1N5940BP-TP over the 1N4755A?

A: The 1N5940BP-TP provides higher power dissipation (1.5 W versus 1 W), lower impedance (53 Ohms versus 70 Ohms), and reduced reverse leakage current (1 µA versus 5 µA). Selection depends on thermal requirements and circuit performance specifications. The lower minimum operating temperature (-55°C versus -65°C) may be a limitation in extreme cold environments.

Q: Are the 2EZ43D5 and 2EZ43D5-TP suitable replacements for the 1N4755A-T?

A: Yes, with considerations. Both parts maintain the 43 V zener voltage and ±5% tolerance. The 2 W power rating provides significant thermal margin. However, the reduced impedance (35 Ohms) and reverse leakage current (500 nA) represent different electrical characteristics that may affect circuit behavior. Verification of circuit performance is necessary when substituting to higher-power devices with different impedance profiles.

Q: What is the significance of RoHS compliance in selecting a substitute?

A: RoHS compliance indicates the part meets European Union restrictions on hazardous substances. The original 1N4755A-T is ROHS3 compliant. For applications subject to RoHS requirements, select substitute parts with ROHS3 or RoHS compliance status. Parts marked as non-compliant are suitable only for applications without RoHS mandates.

Q: Can I use the 1N4755 G from Microsemi as a substitute?

A: The 1N4755 G maintains electrical compatibility with 43 V zener voltage and 1 W power rating. However, the ±10% tolerance is wider than the original ±5%, which may affect circuit precision. Additionally, RoHS non-compliance limits use to applications without RoHS requirements. This part is suitable only when tolerance relaxation and compliance exemption are acceptable.

Q: What does "Impedance (Maximum) 70 Ohms" mean for substitution?

A: Impedance represents the dynamic resistance of the zener diode at operating current. Lower impedance values (such as 35 Ohms in the 2EZ43D5) provide better voltage regulation and lower output impedance. Higher impedance values (70 Ohms) are acceptable for applications with less stringent regulation requirements. Substituting to lower impedance parts improves performance; substituting to higher impedance parts may degrade regulation.

Q: Are all substitute parts available in the same DO-41 package?

A: Yes. All substitute parts listed are supplied in DO-204AL, DO-41, or axial equivalent packages, ensuring mechanical compatibility with the original 1N4755A-T. Packaging format (bulk, tape & reel, tape & box, cut tape) varies by manufacturer and supplier, but the physical component package remains compatible.

Q: What is the impact of operating temperature range differences?

A: The original 1N4755A-T operates from -65°C to 175°C. Substitute parts with extended ranges (such as -65°C to 200°C) provide additional thermal margin. Parts with reduced ranges (such as -55°C to 150°C) may be unsuitable for applications requiring full -65°C to 175°C operation. Verify application temperature requirements before selecting a substitute with a narrower range.

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