TZX13B-TAP Equivalent & Substitute Parts

Part Overview

The TZX13B-TAP is a 13 V, 500 mW Zener diode manufactured by Vishay General Semiconductor - Diodes Division in a through-hole DO-35 (DO-204AH) package. This component is classified as Active and carries AEC-Q101 automotive qualification with ROHS3 compliance. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage applications across automotive and industrial electronics. Substitute parts become necessary due to inventory constraints, supply chain disruptions, or design flexibility requirements while maintaining equivalent electrical and mechanical performance.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	13	V
Power - Maximum	500	mW
Impedance (Maximum)	35	Ohms
Operating Temperature Range	-65 to 175	°C
Package Type	DO-204AH (DO-35)	Axial Through-Hole
Mounting Type	Through Hole	-
RoHS Status	ROHS3 Compliant	-
Grade	Automotive	-

Substitute Part Grouping Explanation

Substitution of the TZX13B-TAP is determined by strict equivalence across the following critical parameters:

Mandatory Equivalence Criteria:

Zener voltage: 13 V nominal
Maximum power dissipation: 500 mW
Package type: DO-204AH (DO-35) axial through-hole configuration
Operating temperature range: minimum -65°C to 175°C
Forward voltage and reverse leakage characteristics within acceptable industrial tolerances

Acceptable Variation Parameters:

Zener voltage tolerance (±5% acceptable for general applications)
Impedance (Zzt) values between 13 and 35 Ohms
Reverse leakage current specifications (100 nA to 1 µA range)
Forward voltage (Vf) between 1.2 V and 1.5 V at specified test currents

All substitute parts listed maintain the 13 V / 500 mW core specification and DO-35 package geometry, ensuring direct mechanical and electrical compatibility in through-hole PCB applications.

Parameter Comparison

Parameter	TZX13B-TAP (Vishay)	1N5243B (Microchip)	1N5243BTR (Fairchild)	BZX79C13-T50A (onsemi)
Voltage - Zener (Nom)	13 V	13 V	13 V	13 V
Tolerance	-	±5%	±5%	±5%
Power - Max	500 mW	500 mW	500 mW	500 mW
Impedance (Max)	35 Ohms	13 Ohms	13 Ohms	30 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 10 V	500 nA @ 9.9 V	500 nA @ 9.9 V	100 nA @ 8 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	1.2 V @ 200 mA	1.5 V @ 100 mA
Operating Temperature	-65°C to 175°C	-65°C to 175°C (TJ)	-65°C to 200°C	-65°C to 200°C
Package / Case	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
RoHS Status	ROHS3 Compliant	RoHS non-compliant	Not specified	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	Not specified	REACH Unaffected

Engineering Selection Recommendations

Primary Substitute: BZX79C13-T50A (onsemi)

The BZX79C13-T50A is the preferred substitute for the TZX13B-TAP. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment. The onsemi part offers an extended operating temperature range (-65°C to 200°C) compared to the Vishay original (-65°C to 175°C), providing additional thermal margin. Impedance specification of 30 Ohms closely matches the original 35 Ohms. Reverse leakage current of 100 nA @ 8 V is superior to the original specification, indicating lower standby current consumption. The part is available in Cut Tape (CT) packaging with 9,926 units in stock.

Secondary Substitute: 1N5243BTR (Fairchild Semiconductor)

The 1N5243BTR provides equivalent electrical performance with identical 13 V / 500 mW ratings and DO-35 package configuration. This part features the lowest forward voltage specification (1.2 V @ 200 mA) among all substitutes, resulting in reduced power dissipation in forward-biased applications. Extended operating temperature range to 200°C exceeds the original specification. However, RoHS compliance status is not specified in available documentation. Inventory availability is 2,109 units in Bulk packaging.

Tertiary Substitute: 1N5243B (Microchip Technology)

The 1N5243B maintains full electrical equivalence with 13 V nominal voltage and 500 mW power rating. Impedance of 13 Ohms is lower than the original, providing improved voltage regulation characteristics. Operating temperature range matches the original at -65°C to 175°C. This part carries RoHS non-compliant status, making it unsuitable for applications requiring ROHS3 certification. Inventory availability is 3,100 units. Use only in non-regulated applications where RoHS compliance is not mandated.

Compliance Considerations:

For automotive applications or designs requiring ROHS3 compliance, select either BZX79C13-T50A or TZX13B-TAP. The 1N5243B must be excluded from regulated supply chains due to RoHS non-compliance status.

Frequently Asked Questions (FAQ)

Q: Can the 1N5243B be used as a direct replacement for the TZX13B-TAP in automotive applications?

A: No. The 1N5243B carries RoHS non-compliant status, while the TZX13B-TAP is ROHS3 compliant. Automotive applications typically require ROHS3 certification. Use BZX79C13-T50A or maintain the original TZX13B-TAP for regulated applications.

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

A: Impedance values of 13, 30, and 35 Ohms represent the dynamic impedance of the Zener diode in the reverse-biased region. Lower impedance (13 Ohms) provides better voltage regulation and lower output impedance. Higher impedance (35 Ohms) results in greater voltage variation with load current changes. All values within this range are functionally acceptable for standard voltage regulation applications.

Q: Are all substitute parts available in the same packaging format?

A: All substitute parts use the DO-204AH (DO-35) axial through-hole package, ensuring identical PCB footprint and mounting compatibility. However, supplier packaging differs: TZX13B-TAP is supplied in Tape & Box (TB), 1N5243B in standard packaging, 1N5243BTR in Bulk, and BZX79C13-T50A in Cut Tape (CT). Verify packaging requirements for your assembly process.

Q: Which substitute offers the best thermal performance?

A: Both 1N5243BTR and BZX79C13-T50A extend the operating temperature range to -65°C to 200°C, compared to the original -65°C to 175°C. This provides 25°C additional thermal margin. For applications operating near temperature limits, either substitute is preferable to the original TZX13B-TAP.

Q: How do reverse leakage current specifications affect circuit performance?

A: Reverse leakage current determines standby power consumption and circuit stability at operating voltage. The BZX79C13-T50A exhibits the lowest leakage (100 nA @ 8 V), followed by 1N5243B and 1N5243BTR (500 nA @ 9.9 V), and the original TZX13B-TAP (1 µA @ 10 V). Lower leakage reduces power dissipation in idle states and improves voltage reference stability.

Q: Can forward voltage differences between substitutes impact circuit design?

A: Forward voltage specifications range from 1.2 V to 1.5 V across all parts. In forward-biased applications (current limiting or protection circuits), the 1N5243BTR with 1.2 V @ 200 mA dissipates less power than alternatives. For voltage regulation applications where the diode operates in reverse bias, forward voltage has negligible impact on circuit performance.

Q: Is the TZX13B-TAP automotive qualified while substitutes are not?

A: The TZX13B-TAP carries AEC-Q101 automotive qualification. Substitute parts do not list AEC-Q101 certification in provided specifications. For applications requiring automotive qualification, the original TZX13B-TAP is the only qualified option. Substitutes are suitable for industrial and commercial applications without automotive qualification requirements.

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