VLZ6V8B-GS18 Equivalent & Substitute Parts

Part Overview

The VLZ6V8B-GS18 is a Zener diode manufactured by Vishay General Semiconductor - Diodes Division, rated at 7.99 V nominal Zener voltage with 500 mW power dissipation in SOD-80 QuadroMELF surface mount packaging. This part is classified as Obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement continuity. The part carries AEC-Q101 automotive qualification and ROHS3 compliance.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	7.99	V
Power - Max	500	mW
Impedance (Max)	8	Ohms
Current - Reverse Leakage @ Vr	7.5 µA @ 7.39 V	µA
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	V
Operating Temperature Range	-65 to 175	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-80 QuadroMELF	—
Grade	Automotive	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the VLZ6V8B-GS18 is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage nominal rating within application tolerance
Maximum power dissipation capacity (500 mW minimum)
Operating temperature range (-65°C to 175°C minimum)
Surface mount mounting type
Reverse leakage current characteristics
Forward voltage characteristics

Grouping Logic:

The substitute parts identified fall into two functional categories based on Zener voltage alignment:

Direct Voltage Equivalent (6.8 V nominal): TLZ6V8B-GS18, 1N4099UR, 1N4099UR-1, 1N5526BUR-1, 1N754AUR-1. These parts operate at 6.8 V nominal Zener voltage, representing a 1.19 V reduction from the original 7.99 V specification. All maintain 500 mW power rating and surface mount configuration.
Package Variant Consideration: TLZ6V8B-GS18 uses SOD-80 MiniMELF packaging, while Microchip Technology alternatives (1N4099UR series, 1N5526BUR-1, 1N754AUR-1) use DO-213AA (Glass) packaging. Both package types are surface mount configurations with different physical footprints.

All substitute parts maintain the -65°C to 175°C operating temperature range and surface mount mounting type required for functional equivalence.

Parameter Comparison

Parameter	VLZ6V8B-GS18	TLZ6V8B-GS18	1N4099UR	1N4099UR-1	1N5526BUR-1	1N754AUR-1
Manufacturer	Vishay	Vishay	Microchip	Microchip	Microchip	Microchip
Voltage - Zener (Nom)	7.99 V	6.8 V	6.8 V	6.8 V	6.8 V	6.8 V
Tolerance	—	—	±5%	±5%	±5%	±5%
Power - Max	500 mW	500 mW	500 mW	500 mW	500 mW	500 mW
Impedance (Max)	8 Ohms	8 Ohms	200 Ohms	200 Ohms	30 Ohms	3 Ohms
Current - Reverse Leakage @ Vr	7.5 µA @ 7.39 V	2 µA @ 4 V	1 µA @ 5.17 V	1 µA @ 5.2 V	1 µA @ 6.2 V	2 µA @ 4 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	1.1 V @ 200 mA	1.1 V @ 200 mA
Operating Temperature	-65 to 175°C	-65 to 175°C	-65 to 175°C	-65 to 175°C	-65 to 175°C	-65 to 175°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	SOD-80 QuadroMELF	SOD-80 MiniMELF	DO-213AA (Glass)	DO-213AA	DO-213AA	DO-213AA
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant	RoHS non-compliant	RoHS non-compliant	RoHS non-compliant
Grade	Automotive	—	—	—	—	—
Qualification	AEC-Q101	—	—	—	—	—

Engineering Selection Recommendations

Primary Recommendation: TLZ6V8B-GS18

The TLZ6V8B-GS18 is the preferred substitute for the obsolete VLZ6V8B-GS18. Both parts are manufactured by Vishay General Semiconductor - Diodes Division and maintain identical electrical specifications for power dissipation (500 mW), impedance (8 Ohms), forward voltage characteristics (1.5 V @ 200 mA), and operating temperature range (-65°C to 175°C). The TLZ6V8B-GS18 carries Active product status with ROHS3 compliance. The primary difference is Zener voltage (6.8 V nominal versus 7.99 V nominal) and package variant (SOD-80 MiniMELF versus SOD-80 QuadroMELF). Both are SOD-80 surface mount packages with different physical footprints. Inventory availability is 10,881 pieces.

Secondary Recommendations: Microchip Technology 1N754AUR-1, 1N4099UR, 1N4099UR-1, 1N5526BUR-1

These Microchip Technology alternatives provide 6.8 V nominal Zener voltage with 500 mW power rating and -65°C to 175°C operating temperature range. All use DO-213AA (Glass) surface mount packaging. Key differences from the original part include:

RoHS non-compliance status (original part is ROHS3 compliant)
Absence of automotive grade and AEC-Q101 qualification (original part carries both)
Reduced forward voltage (1.1 V @ 200 mA versus 1.5 V @ 200 mA)
Varying impedance characteristics (3 to 200 Ohms versus 8 Ohms)

These parts are suitable for applications where RoHS compliance is not mandated and automotive qualification is not required. Inventory availability ranges from 697 to 1,078 pieces across the four part numbers.

Compliance Considerations:

The original VLZ6V8B-GS18 carries AEC-Q101 automotive qualification and ROHS3 compliance. The TLZ6V8B-GS18 maintains ROHS3 compliance but does not specify automotive qualification. Microchip alternatives do not carry ROHS3 compliance or automotive qualification. Selection should account for application requirements regarding regulatory compliance and automotive standards.

Frequently Asked Questions (FAQ)

Q: Why is the VLZ6V8B-GS18 marked as Obsolete?

A: The VLZ6V8B-GS18 is classified as Obsolete by the manufacturer, indicating it is no longer in active production. Substitute parts must be identified for new designs and ongoing procurement requirements.

Q: Can I use a 6.8 V Zener diode as a substitute for a 7.99 V part?

A: Substitution depends on circuit design requirements. The 6.8 V nominal rating represents a 1.19 V reduction from the original 7.99 V specification. Circuit voltage regulation and protection thresholds must accommodate this difference. Electrical validation is required for each application.

Q: What is the difference between SOD-80 QuadroMELF and SOD-80 MiniMELF packaging?

A: Both are SOD-80 surface mount packages with different physical dimensions and footprints. QuadroMELF and MiniMELF variants have distinct land patterns on printed circuit boards. PCB layout compatibility must be verified before substitution.

Q: What is the difference between SOD-80 and DO-213AA packaging?

A: SOD-80 and DO-213AA are distinct surface mount package types with different physical dimensions and footprints. Direct substitution requires PCB redesign to accommodate the different land pattern. These packages are not pin-compatible.

Q: Why do the Microchip alternatives show RoHS non-compliance?

A: The Microchip Technology parts (1N4099UR series, 1N5526BUR-1, 1N754AUR-1) are listed as RoHS non-compliant in the provided specifications. Applications requiring ROHS3 compliance should prioritize the TLZ6V8B-GS18, which maintains ROHS3 compliance status.

Q: Does the TLZ6V8B-GS18 carry automotive qualification?

A: The TLZ6V8B-GS18 does not specify automotive grade or AEC-Q101 qualification in the provided data. The original VLZ6V8B-GS18 carries AEC-Q101 automotive qualification. Applications requiring automotive qualification should evaluate qualification requirements independently.

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

A: Impedance (Zzt) affects dynamic response and noise characteristics in voltage regulation circuits. The original part specifies 8 Ohms maximum impedance. Substitute parts range from 3 to 200 Ohms. Lower impedance values provide better high-frequency response. Circuit performance validation is required when impedance differs significantly.

Q: How do reverse leakage current specifications compare?

A: Reverse leakage current affects circuit quiescent current and long-term reliability. The original VLZ6V8B-GS18 specifies 7.5 µA @ 7.39 V. Substitute parts range from 1 to 2 µA at different voltage points. Lower leakage current generally indicates better long-term performance in low-power applications.

Q: Can I substitute parts with different forward voltage ratings?

A: Forward voltage affects power dissipation in forward-biased conditions. The original part specifies 1.5 V @ 200 mA, while Microchip alternatives specify 1.1 V @ 200 mA. This 0.4 V difference impacts power dissipation calculations. Circuit thermal analysis should be updated for substitute parts with different forward voltage characteristics.

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