TZX13B-TR Equivalent & Substitute Parts

Part Overview

The TZX13B-TR is a 13 V, 500 mW Zener diode manufactured by Vishay General Semiconductor - Diodes Division in the DO-35 (DO-204AH) through-hole package. This component is classified as an active product with AEC-Q101 automotive qualification and ROHS3 compliance. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage circuits. Equivalent and substitute parts are identified to support design flexibility, supply chain continuity, and application-specific performance requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	13	V
Power - Max	500	mW
Impedance (Max)	35	Ohms
Current - Reverse Leakage @ Vr	1	µA @ 10 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, Axial	-

Substitute Part Grouping Explanation

Substitution of the TZX13B-TR is determined by the following critical parameters:

Primary Substitution Criteria:

Nominal Zener voltage: 13 V (±5% tolerance acceptable)
Maximum power dissipation: 500 mW
Package type: DO-35 (DO-204AH) through-hole axial configuration
Operating temperature range: minimum -65°C to 175°C

Secondary Compatibility Factors:

Impedance (Zzt): Maximum 35 Ohms (lower impedance values indicate improved performance)
Reverse leakage current: Lower values preferred for reduced standby current
Forward voltage (Vf): Maximum 1.5 V @ 200 mA
RoHS and REACH compliance status

Substitute parts must maintain electrical equivalence within the specified voltage and power ratings while supporting the through-hole DO-35 package form factor. Tolerance variations and impedance differences are acceptable provided the part functions within the application's voltage regulation and protection requirements.

Parameter Comparison

Parameter	TZX13B-TR (Vishay)	1N5243B (Microchip)	1N5243B TR PBFREE (Central Semi)	1N5243BTR (Fairchild)	BZX79C13-T50A (onsemi)	NZX13B,133 (Nexperia)
Voltage - Zener (Nom)	13 V	13 V	13 V	13 V	13 V	12.85 V
Tolerance	-	±5%	±5%	±5%	±5%	±2%
Power - Max	500 mW	500 mW	500 mW	500 mW	500 mW	500 mW
Impedance (Max)	35 Ohms	13 Ohms	13 Ohms	13 Ohms	30 Ohms	35 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 10 V	500 nA @ 9.9 V	500 nA @ 9.9 V	500 nA @ 9.9 V	100 nA @ 8 V	100 nA @ 8 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	1.1 V @ 200 mA	1.2 V @ 200 mA	1.5 V @ 100 mA	1.5 V @ 200 mA
Operating Temperature Range	-65 to 175°C	-65 to 175°C	-65 to 200°C	-65 to 200°C	-65 to 200°C	-55 to 175°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	RoHS non-compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalents (Preferred for Drop-In Replacement):

1N5243B TR PBFREE (Central Semiconductor Corp) and BZX79C13-T50A (onsemi) are the primary substitutes for the TZX13B-TR. Both parts maintain 13 V nominal Zener voltage, 500 mW power rating, and DO-35 package compatibility. The 1N5243B TR PBFREE offers extended operating temperature range (-65 to 200°C) and ROHS3 compliance, matching the automotive-grade requirements of the original part. The BZX79C13-T50A provides improved reverse leakage characteristics (100 nA @ 8 V) and ROHS3 compliance with comparable impedance performance.

Secondary Substitutes (Application-Dependent):

1N5243BTR (Fairchild Semiconductor) is electrically equivalent with ±5% voltage tolerance and 500 mW power rating. This part is suitable for applications where extended temperature operation (-65 to 200°C) is required. The 1N5243B (Microchip Technology) maintains core electrical specifications but operates only to 175°C and carries RoHS non-compliant status, limiting its use in new designs requiring environmental compliance.

Voltage-Variant Substitute:

NZX13B,133 (Nexperia USA Inc.) operates at 12.85 V nominal with ±2% tolerance, providing tighter voltage control than the ±5% tolerance alternatives. This part is suitable for applications requiring precise voltage regulation. However, the operating temperature range (-55 to 175°C) is limited at the lower bound compared to the TZX13B-TR.

Compliance Considerations:

For applications requiring AEC-Q101 automotive qualification and ROHS3 compliance, the 1N5243B TR PBFREE and BZX79C13-T50A are the recommended selections. The TZX13B-TR carries explicit AEC-Q101 qualification; substitute parts should be verified against specific automotive qualification requirements in the application design.

Frequently Asked Questions (FAQ)

Q: Can the 1N5243B (Microchip) be used as a direct replacement for the TZX13B-TR?

A: The 1N5243B is electrically equivalent in voltage (13 V) and power (500 mW) specifications and uses the same DO-35 package. However, it is RoHS non-compliant and operates only to 175°C, matching the TZX13B-TR upper temperature limit. For new designs, ROHS3-compliant alternatives such as 1N5243B TR PBFREE or BZX79C13-T50A are preferred.

Q: What is the difference between the 1N5243B TR PBFREE and 1N5243BTR?

A: Both parts are 13 V, 500 mW Zener diodes in DO-35 packages with ±5% tolerance. The 1N5243B TR PBFREE (Central Semiconductor) is ROHS3 compliant with extended temperature range (-65 to 200°C) and lower forward voltage (1.1 V @ 200 mA). The 1N5243BTR (Fairchild) also extends to 200°C but specifies 1.2 V forward voltage. The "TR PBFREE" designation indicates lead-free construction.

Q: Is the NZX13B,133 suitable for applications requiring 13 V regulation?

A: The NZX13B,133 operates at 12.85 V nominal with ±2% tolerance, resulting in a voltage range of 12.59 V to 13.11 V. This is within the 13 V specification band and provides tighter tolerance control. However, applications requiring exactly 13 V ±5% should verify that the 12.85 V nominal value meets circuit requirements. The lower operating temperature minimum (-55°C vs. -65°C) may also be a limiting factor in extreme cold environments.

Q: How do impedance differences affect substitution?

A: Impedance (Zzt) affects the Zener diode's dynamic resistance and voltage regulation performance. The TZX13B-TR specifies 35 Ohms maximum impedance. Substitute parts with lower impedance (1N5243B, 1N5243B TR PBFREE, 1N5243BTR at 13 Ohms) provide improved voltage regulation and reduced output impedance, resulting in better performance. The BZX79C13-T50A (30 Ohms) and NZX13B,133 (35 Ohms) are comparable to the original specification.

Q: What is the significance of reverse leakage current differences?

A: Reverse leakage current determines standby power consumption and circuit performance at low currents. The TZX13B-TR specifies 1 µA @ 10 V, while most substitutes specify 500 nA @ 9.9 V or lower (BZX79C13-T50A and NZX13B,133 at 100 nA @ 8 V). Lower leakage current reduces power dissipation in standby conditions and improves circuit efficiency. Substitutes with lower leakage are functionally superior in this parameter.

Q: Are all substitute parts available in Cut Tape (CT) packaging?

A: The TZX13B-TR is supplied in Cut Tape packaging. Substitute availability varies: 1N5243B TR PBFREE and BZX79C13-T50A are available in Cut Tape; 1N5243B packaging is not specified; 1N5243BTR is supplied in Bulk; NZX13B,133 is available in Cut Tape. Packaging selection depends on manufacturing and assembly requirements.

Q: Can the BZX79C13-T50A replace the TZX13B-TR in automotive applications?

A: The BZX79C13-T50A is a 13 V, 500 mW Zener diode in DO-35 package with ROHS3 compliance and extended temperature range (-65 to 200°C). It meets the core electrical specifications for substitution. However, the original TZX13B-TR carries explicit AEC-Q101 automotive qualification. Verify that the BZX79C13-T50A meets specific automotive qualification requirements for the application before implementation.

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