VLZ30B-GS18 Equivalent & Substitute Parts

Part Overview

The VLZ30B-GS18 is a Zener diode rated at 28.42 V, 500 mW, manufactured by Vishay General Semiconductor - Diodes Division in SOD-80 QuadroMELF surface mount package. This component is classified as obsolete, requiring identification of equivalent alternatives for new designs or production continuity. The part carries AEC-Q101 automotive qualification and ROHS3 compliance. Substitute parts must maintain electrical performance within the specified operating parameters while accommodating the obsolete status of the original component.

Key Parameters

Parameter	VLZ30B-GS18
Voltage - Zener (Nom)	28.42 V
Power - Max	500 mW
Impedance (Max)	55 Ohms
Current - Reverse Leakage @ Vr	40 µA @ 26.3 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 QuadroMELF
Product Status	Obsolete
Grade	Automotive
Qualification	AEC-Q101
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the VLZ30B-GS18 is determined by the following critical parameters:

Electrical Compatibility Criteria:

Zener voltage rating within acceptable tolerance of 28.42 V
Power dissipation capacity of 500 mW minimum
Operating temperature range of -65°C to 175°C minimum
Surface mount technology requirement
Reverse leakage current and forward voltage characteristics

Mechanical Compatibility Criteria:

Surface mount package format (SOD-80 or equivalent DO-213 variants)
Pin configuration compatibility with PCB layout

Compliance Criteria:

RoHS3 compliance for environmental standards
REACH compliance status
Automotive grade qualification preferred for AEC-Q101 applications

The two substitute parts identified (TLZ30B-GS18 and 1N5545BUR-1) satisfy the core electrical requirements while offering active product status and improved availability compared to the obsolete VLZ30B-GS18.

Parameter Comparison

Parameter	VLZ30B-GS18	TLZ30B-GS18	1N5545BUR-1
Manufacturer	Vishay General Semiconductor	Vishay General Semiconductor	Microchip Technology
Voltage - Zener (Nom)	28.42 V	30 V	30 V
Voltage - Zener Tolerance	-	-	±5%
Power - Max	500 mW	500 mW	500 mW
Impedance (Max)	55 Ohms	80 Ohms	100 Ohms
Current - Reverse Leakage @ Vr	40 µA @ 26.3 V	40 nA @ 26.3 V	10 nA @ 27 V
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	1.1 V @ 200 mA
Operating Temperature Range	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	SOD-80 QuadroMELF	SOD-80 MiniMELF	DO-213AA
Product Status	Obsolete	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant
Current Inventory	964 Pcs	1095 Pcs	967 Pcs

Engineering Selection Recommendations

TLZ30B-GS18 (Vishay General Semiconductor):

This substitute is the primary equivalent for VLZ30B-GS18 replacement. Both components are manufactured by Vishay General Semiconductor within the same product family (TLZ vs. VLZ series). The TLZ30B-GS18 maintains identical power rating (500 mW), operating temperature range (-65°C to 175°C), and forward voltage characteristics (1.5 V @ 200 mA). The zener voltage is rated at 30 V compared to 28.42 V, representing a 5.6% increase. The impedance increases from 55 Ohms to 80 Ohms. Reverse leakage current improves significantly from 40 µA to 40 nA. The component is active in production status with ROHS3 compliance. Package format changes from SOD-80 QuadroMELF to SOD-80 MiniMELF, requiring PCB layout verification for pin-to-pin compatibility.

1N5545BUR-1 (Microchip Technology):

This substitute provides an alternative from a different manufacturer with active product status. The component maintains the 500 mW power rating and -65°C to 175°C operating temperature range. Zener voltage is 30 V with ±5% tolerance specification. Impedance is 100 Ohms, and reverse leakage current is 10 nA at 27 V, both superior to the original part. Forward voltage is reduced to 1.1 V @ 200 mA. The package format is DO-213AA, differing from the original SOD-80 QuadroMELF. Critical limitation: this component is RoHS non-compliant, which may restrict use in applications requiring environmental compliance certification. Automotive qualification status is not specified for this part.

Selection Criteria:

For applications requiring ROHS3 compliance and automotive qualification, TLZ30B-GS18 is the recommended substitute. For applications where RoHS compliance is not mandatory and cost optimization is prioritized, 1N5545BUR-1 provides an alternative with improved electrical characteristics. Package compatibility with existing PCB layouts must be verified before final selection.

Frequently Asked Questions (FAQ)

Q: Can TLZ30B-GS18 directly replace VLZ30B-GS18 without circuit redesign?

A: Electrical substitution is feasible within circuit tolerance margins. The zener voltage difference (30 V vs. 28.42 V) represents a 5.6% increase. The impedance increase from 55 Ohms to 80 Ohms affects voltage regulation characteristics. PCB layout modification is required due to package format change from SOD-80 QuadroMELF to SOD-80 MiniMELF. Circuit simulation or testing is necessary to confirm performance within application specifications.

Q: What is the primary difference between TLZ30B-GS18 and 1N5545BUR-1?

A: Both components meet the 500 mW power and -65°C to 175°C temperature requirements. TLZ30B-GS18 is ROHS3 compliant and maintains Vishay manufacturing continuity. 1N5545BUR-1 is RoHS non-compliant but offers superior reverse leakage current (10 nA vs. 40 nA) and lower forward voltage (1.1 V vs. 1.5 V). Package formats differ: SOD-80 MiniMELF vs. DO-213AA.

Q: Is automotive qualification maintained with substitute parts?

A: TLZ30B-GS18 does not explicitly list AEC-Q101 qualification in the provided specifications. 1N5545BUR-1 does not specify automotive grade qualification. If AEC-Q101 certification is required for the application, verification with manufacturers is necessary before substitution.

Q: How does the impedance change affect circuit performance?

A: Impedance increases from 55 Ohms (VLZ30B-GS18) to 80 Ohms (TLZ30B-GS18) or 100 Ohms (1N5545BUR-1). Higher impedance reduces voltage regulation capability and increases output impedance in voltage regulation circuits. Applications with tight voltage tolerance requirements must evaluate this parameter against circuit specifications.

Q: Are the package dimensions compatible with existing PCB layouts?

A: VLZ30B-GS18 uses SOD-80 QuadroMELF package. TLZ30B-GS18 uses SOD-80 MiniMELF package. 1N5545BUR-1 uses DO-213AA package. While all are surface mount SOD-80 variants, physical dimensions and pin spacing differ. PCB footprint verification is mandatory before component substitution.

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

A: VLZ30B-GS18 specifies 40 µA reverse leakage at 26.3 V. TLZ30B-GS18 specifies 40 nA at 26.3 V (1000× improvement). 1N5545BUR-1 specifies 10 nA at 27 V (4000× improvement). Lower leakage current reduces standby power consumption and improves voltage stability in high-impedance circuits. Applications sensitive to leakage current benefit from substitute parts.

Q: Can 1N5545BUR-1 be used in RoHS-compliant applications?

A: No. 1N5545BUR-1 is specified as RoHS non-compliant. Applications requiring RoHS3 compliance must use TLZ30B-GS18 or identify alternative RoHS-compliant 30 V zener diodes from other manufacturers.

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