VLZ20B-GS18 Equivalent & Substitute Parts

Part Overview

The VLZ20B-GS18 is a Zener Diode rated at 19.11 V with 500 mW power dissipation in a SOD-80 QuadroMELF surface mount package, manufactured by Vishay General Semiconductor - Diodes Division. This component is classified as Obsolete, which necessitates identification of equivalent and substitute parts for ongoing design support and procurement continuity. The part carries AEC-Q101 automotive qualification and is ROHS3 compliant.

Key Parameters

Parameter	Value
Voltage - Zener (Nom) (Vz)	19.11 V
Power - Max	500 mW
Impedance (Max) (Zzt)	28 Ohms
Current - Reverse Leakage @ Vr	40 µA @ 17.1 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA
Operating Temperature Range	-65°C ~ 175°C
Mounting Type	Surface Mount
Package / Case	SOD-80 Variant
Grade	Automotive
Qualification	AEC-Q101
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the VLZ20B-GS18 is determined by the following critical parameters:

Electrical Compatibility Criteria:

Zener voltage within acceptable tolerance of 19.11 V nominal
Power dissipation rating of 500 mW or greater
Operating temperature range of -65°C to 175°C or broader
Surface mount configuration

Mechanical Compatibility Criteria:

Surface mount package format
Physical footprint compatibility with SOD-80 or equivalent package designations

The substitute parts identified maintain the 500 mW power rating and -65°C to 175°C operating temperature range. Zener voltage specifications range from 19.11 V to 20 V, representing a nominal shift within typical design tolerance windows for voltage regulation applications. All substitutes are surface mount devices suitable for automated assembly processes.

Parameter Comparison

Parameter	VLZ20B-GS18 (Main)	TLZ20B-GS18	1N4114UR-1	1N5540BUR-1
Manufacturer	Vishay General Semiconductor	Vishay General Semiconductor	Microchip Technology	Microchip Technology
Voltage - Zener (Nom) (Vz)	19.11 V	20 V	20 V	20 V
Power - Max	500 mW	500 mW	500 mW	500 mW
Impedance (Max) (Zzt)	28 Ohms	28 Ohms	150 Ohms	100 Ohms
Current - Reverse Leakage @ Vr	40 µA @ 17.1 V	40 nA @ 17.7 V	10 nA @ 15.2 V	10 nA @ 18 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	1.1 V @ 200 mA	1.1 V @ 200 mA
Operating Temperature Range	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	SOD-80 QuadroMELF	SOD-80 MiniMELF	DO-213AA	DO-213AA
Product Status	Obsolete	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant

Engineering Selection Recommendations

TLZ20B-GS18 (Vishay General Semiconductor - Diodes Division)

The TLZ20B-GS18 represents the primary direct substitute for the VLZ20B-GS18. Both components are manufactured by Vishay General Semiconductor - Diodes Division and share identical electrical specifications: 500 mW power rating, 28 Ohms maximum impedance, and -65°C to 175°C operating temperature range. The TLZ20B-GS18 operates at 20 V nominal Zener voltage compared to the main part's 19.11 V, a 0.89 V differential suitable for voltage regulation circuits. The TLZ20B-GS18 is Active status with ROHS3 compliance and carries superior reverse leakage characteristics (40 nA versus 40 µA). Package format transitions from SOD-80 QuadroMELF to SOD-80 MiniMELF, maintaining surface mount compatibility with potential PCB layout adjustments.

1N4114UR-1 (Microchip Technology)

The 1N4114UR-1 is an Active status Zener Diode from Microchip Technology rated at 20 V with 500 mW power dissipation and ROHS3 compliance. This part operates within the same temperature range (-65°C to 175°C) and maintains surface mount configuration. The impedance specification of 150 Ohms is higher than the main part (28 Ohms), and forward voltage is reduced to 1.1 V at 200 mA. Package format is DO-213AA (Glass), requiring PCB layout modification from the original SOD-80 QuadroMELF footprint.

1N5540BUR-1 (Microchip Technology)

The 1N5540BUR-1 is an Active status Zener Diode from Microchip Technology with 20 V nominal voltage and 500 mW power rating. Operating temperature range matches the main part at -65°C to 175°C. Impedance is specified at 100 Ohms maximum. This part is RoHS non-compliant, which may restrict use in applications requiring RoHS certification. Package format is DO-213AA, requiring PCB footprint modification.

Frequently Asked Questions (FAQ)

Q: Can the TLZ20B-GS18 be used as a direct replacement for the VLZ20B-GS18?

A: The TLZ20B-GS18 is electrically compatible with the VLZ20B-GS18 for voltage regulation applications. Both components share 500 mW power rating, 28 Ohms impedance, and identical operating temperature range. The Zener voltage difference of 0.89 V (20 V versus 19.11 V) is within typical design tolerance windows. Package format differs (SOD-80 MiniMELF versus SOD-80 QuadroMELF), requiring verification of PCB footprint compatibility.

Q: What are the key differences between the Vishay and Microchip substitute options?

A: The Vishay TLZ20B-GS18 maintains the lowest impedance specification (28 Ohms) matching the original part, while Microchip options (1N4114UR-1 and 1N5540BUR-1) specify higher impedance values (150 Ohms and 100 Ohms respectively). Reverse leakage current is significantly lower in Microchip parts (10 nA) compared to both Vishay options. Forward voltage is reduced in Microchip parts (1.1 V) versus Vishay parts (1.5 V). Package formats differ: Vishay maintains SOD-80 variants while Microchip uses DO-213AA.

Q: Are there RoHS compliance considerations for substitute selection?

A: The VLZ20B-GS18 and TLZ20B-GS18 are both ROHS3 compliant. The 1N4114UR-1 is ROHS3 compliant. The 1N5540BUR-1 is RoHS non-compliant. Applications requiring RoHS certification should exclude the 1N5540BUR-1 from consideration.

Q: How do package format differences affect PCB design?

A: The main part uses SOD-80 QuadroMELF package. The TLZ20B-GS18 uses SOD-80 MiniMELF, a related but distinct SOD-80 variant. The Microchip options (1N4114UR-1 and 1N5540BUR-1) use DO-213AA package format. PCB footprint libraries and assembly specifications must be verified for compatibility with the selected substitute part.

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

A: Impedance (Zzt) affects voltage regulation stability and transient response. The VLZ20B-GS18 and TLZ20B-GS18 specify 28 Ohms maximum impedance, providing superior regulation characteristics. The 1N4114UR-1 at 150 Ohms and 1N5540BUR-1 at 100 Ohms exhibit higher impedance, which may impact circuit performance in applications requiring tight voltage regulation or fast transient response.

Q: Can the Microchip parts be used in automotive applications?

A: The VLZ20B-GS18 carries AEC-Q101 automotive qualification. The substitute parts provided do not include automotive qualification specifications in the available data. Automotive application requirements should be verified against component datasheets and qualification documentation before selection.

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