TZX4V3B-TAP Equivalent & Substitute Parts

Part Overview

The TZX4V3B-TAP is a 4.3 V Zener diode rated at 500 mW in a DO-35 through-hole package, manufactured by Vishay General Semiconductor - Diodes Division. This component is classified as Active and carries AEC-Q101 automotive qualification. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage applications across automotive and industrial electronics. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	4.3	V
Power - Max	500	mW
Impedance (Max)	100	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 1.5 V
Voltage - Forward (Vf) (Max) @ If	1.5	V @ 200 mA
Operating Temperature Range	-65 to 175	°C
Mounting Type	Through Hole	-
Package / Case	DO-204AH (DO-35)	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the TZX4V3B-TAP is determined by the following critical parameters:

Electrical Compatibility Criteria:

Zener voltage (Vz) must be 4.3 V nominal
Maximum power dissipation must be 500 mW or greater
Operating temperature range must encompass the application requirements
Reverse leakage current must not exceed specified limits
Forward voltage characteristics must be compatible with circuit design

Mechanical Compatibility Criteria:

Package type must be DO-35 (DO-204AH) through-hole axial configuration
Lead spacing and physical dimensions must match the original footprint

Compliance Criteria:

RoHS3 compliance required
REACH unaffected status required
ECCN EAR99 classification maintained

All identified substitute parts meet these criteria and are classified as Active products with current manufacturing status.

Parameter Comparison

Parameter	TZX4V3B-TAP (Main)	BZX79C4V3	BZX79C4V3-T50A	1N5229B	1N749A BK PBFREE	1N749A TR PBFREE
Manufacturer	Vishay	Taiwan Semiconductor	onsemi	Taiwan Semiconductor	Central Semiconductor	Central Semiconductor
Voltage - Zener (Nom)	4.3 V	4.3 V	4.3 V	4.3 V	4.3 V	4.3 V
Tolerance	-	±5%	±5%	±5%	±5%	±5%
Power - Max	500 mW	500 mW	500 mW	500 mW	500 mW	500 mW
Impedance (Max)	100 Ohms	90 Ohms	90 Ohms	22 Ohms	22 Ohms	22 Ohms
Current - Reverse Leakage @ Vr	5 µA @ 1.5 V	5 µA @ 1 V	5 µA @ 1 V	5 µA @ 1 V	2 µA @ 1 V	2 µA @ 1 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 100 mA	1.5 V @ 100 mA	1.1 V @ 200 mA	1.5 V @ 200 mA	1.5 V @ 200 mA
Operating Temperature Range	-65 to 175°C	-65 to 175°C	-65 to 200°C	Up to 200°C	-65 to 200°C	-65 to 200°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	DO-204AH (DO-35)	DO-204AH (DO-35)	DO-204AH (DO-35)	DO-204AH (DO-35)	DO-204AH (DO-35)	DO-204AH (DO-35)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Upgrade Category):

BZX79C4V3 and BZX79C4V3-T50A are classified as upgrade substitutes. Both maintain the 4.3 V nominal zener voltage and 500 mW power rating with identical package configuration. BZX79C4V3-T50A from onsemi extends the operating temperature range to 200°C, providing enhanced thermal performance compared to the main part's 175°C maximum. Both parts carry ROHS3 compliance and REACH unaffected status.

Manufacturer Recommended Substitutes:

1N5229B, 1N749A BK PBFREE, and 1N749A TR PBFREE are designated as manufacturer-recommended alternatives. These parts maintain electrical equivalence with 4.3 V nominal zener voltage and 500 mW power rating. The 1N749A variants from Central Semiconductor Corp feature lower impedance (22 Ohms versus 100 Ohms on the main part) and reduced reverse leakage current (2 µA versus 5 µA), with extended operating temperature to 200°C. The 1N5229B from Taiwan Semiconductor Corp similarly offers lower impedance and extended temperature range. All three parts are ROHS3 compliant and REACH unaffected.

Packaging Considerations:

The main part TZX4V3B-TAP is supplied in Tape & Box (TB) packaging. Substitute parts are available in alternative packaging formats: BZX79C4V3 in Tape & Reel (TR), BZX79C4V3-T50A in Tape & Box (TB), 1N5229B in Tape & Reel (TR), 1N749A BK PBFREE in Bulk, and 1N749A TR PBFREE in Cut Tape (CT). Packaging selection should align with assembly process requirements and inventory management protocols.

Compliance Status:

All substitute parts maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment with the original component. ECCN classification remains EAR99 across all alternatives.

Frequently Asked Questions (FAQ)

Q: Can BZX79C4V3 be used as a direct replacement for TZX4V3B-TAP?

A: Yes. Both parts share identical nominal zener voltage (4.3 V), maximum power dissipation (500 mW), and DO-35 package configuration. Electrical parameters are compatible for circuit operation. The primary difference is packaging format (Tape & Reel versus Tape & Box).

Q: What is the significance of impedance differences between substitute parts?

A: Impedance (Zzt) affects the dynamic resistance of the zener diode at specified current levels. The main part specifies 100 Ohms maximum impedance, while 1N5229B and 1N749A variants specify 22 Ohms. Lower impedance provides better voltage regulation stability and reduced output impedance in voltage reference applications. Selection depends on circuit requirements for voltage stability and transient response.

Q: Are the 1N749A variants suitable for automotive applications?

A: The 1N749A BK PBFREE and 1N749A TR PBFREE are electrically equivalent to the TZX4V3B-TAP and meet ROHS3 and REACH requirements. However, the main part carries AEC-Q101 automotive qualification. Use of non-AEC-qualified substitutes in automotive applications requires design review and qualification assessment per applicable automotive standards.

Q: What is the difference between 1N749A BK PBFREE and 1N749A TR PBFREE?

A: Both parts are electrically identical 4.3 V, 500 mW zener diodes from Central Semiconductor Corp. The difference is packaging format: BK PBFREE is supplied in Bulk packaging, while TR PBFREE is supplied in Cut Tape (CT) packaging. Selection is based on assembly process compatibility and inventory handling requirements.

Q: Does BZX79C4V3-T50A offer advantages over BZX79C4V3?

A: BZX79C4V3-T50A extends the maximum operating temperature to 200°C compared to BZX79C4V3 at 175°C. Both parts are electrically equivalent with 4.3 V nominal zener voltage and 500 mW power rating. The extended temperature range of BZX79C4V3-T50A provides thermal margin for high-temperature operating environments.

Q: Can substitute parts be mixed in the same assembly?

A: All substitute parts meet the same electrical and mechanical specifications for the 4.3 V, 500 mW DO-35 zener diode category. Mixing different manufacturers or part numbers in the same assembly is permissible from an electrical standpoint, provided all parts meet the circuit design requirements. Assembly and quality control procedures should address traceability and documentation of part selection.

Q: What is the impact of forward voltage differences on circuit design?

A: Forward voltage (Vf) specifications vary among substitutes. The main part specifies 1.5 V @ 200 mA, while 1N5229B specifies 1.1 V @ 200 mA. Forward voltage affects reverse-biased leakage current behavior and forward-biased conduction characteristics. Circuit designs relying on specific forward voltage characteristics should confirm compatibility with selected substitute parts.

Q: Are all substitute parts currently in stock?

A: Inventory status is provided for reference: BZX79C4V3 (854 Pcs), BZX79C4V3-T50A (904 Pcs), 1N5229B (6300 Pcs), 1N749A BK PBFREE (16224 Pcs), and 1N749A TR PBFREE (11362 Pcs). Inventory levels are subject to change and should be confirmed at time of procurement.

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