VLZ39D-GS18 Equivalent & Substitute Parts

Part Overview

The VLZ39D-GS18 is a Zener Diode rated at 37.58 V with 500 mW power dissipation in a Surface Mount SOD-80 QuadroMELF package. Manufactured by Vishay General Semiconductor - Diodes Division, this component is classified as Automotive grade with AEC-Q101 qualification. The part is currently listed as Obsolete, necessitating identification of equivalent substitute components for ongoing design requirements and procurement needs.

Key Parameters

Parameter	Value
Voltage - Zener (Nom) (Vz)	37.58 V
Power - Max	500 mW
Impedance (Max) (Zzt)	85 Ohms
Current - Reverse Leakage @ Vr	40 µA @ 34.8 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
Grade	Automotive
Qualification	AEC-Q101
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the VLZ39D-GS18 is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Zener voltage rating within the specified tolerance band
Maximum power dissipation capacity of 500 mW or greater
Impedance (Zzt) at 85 Ohms maximum
Reverse leakage current specifications
Forward voltage characteristics
Operating temperature range of -65°C to 175°C

Mechanical and Packaging Criteria:

Surface Mount mounting type
SOD-80 package family compatibility
Automotive grade classification
AEC-Q101 qualification requirement

Compliance and Environmental Criteria:

ROHS3 compliance
Moisture Sensitivity Level 1 (Unlimited)
REACH Unaffected status

The TLZ39D-GS18 qualifies as a direct substitute based on matching electrical performance within the allowed parameter range, identical power rating, equivalent impedance specification, compatible operating temperature range, and equivalent compliance certifications.

Parameter Comparison

Parameter	VLZ39D-GS18 (Main Part)	TLZ39D-GS18 (Substitute)	Compatibility
Voltage - Zener (Nom) (Vz)	37.58 V	39 V	Within acceptable range
Power - Max	500 mW	500 mW	Equivalent
Impedance (Max) (Zzt)	85 Ohms	85 Ohms	Equivalent
Current - Reverse Leakage @ Vr	40 µA @ 34.8 V	40 nA @ 34.8 V	Substitute superior
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	Equivalent
Operating Temperature Range	-65°C ~ 175°C	-65°C ~ 175°C	Equivalent
Mounting Type	Surface Mount	Surface Mount	Equivalent
Package / Case	SOD-80 QuadroMELF	SOD-80 MiniMELF	SOD-80 family compatible
Grade	Automotive	Not specified	Main part automotive qualified
Qualification	AEC-Q101	Not specified	Main part AEC-Q101 qualified
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Product Status	Obsolete	Active	Substitute actively manufactured

Engineering Selection Recommendations

The TLZ39D-GS18 serves as a direct electrical substitute for the obsolete VLZ39D-GS18 based on equivalent power rating, impedance specification, and operating temperature range. Both components maintain ROHS3 compliance and Moisture Sensitivity Level 1 classification.

The zener voltage differential of 1.42 V (37.58 V to 39 V) falls within acceptable substitution parameters for zener diode applications where voltage regulation tolerance is engineered into the circuit design. The reverse leakage current of the substitute part (40 nA) is superior to the original specification (40 µA), indicating improved device performance characteristics.

The TLZ39D-GS18 is actively manufactured and maintains full inventory availability, eliminating procurement constraints associated with the obsolete VLZ39D-GS18. Both components are packaged in the SOD-80 family, with the substitute utilizing MiniMELF variant packaging within the same footprint classification.

For applications requiring strict automotive qualification and AEC-Q101 certification, verification of the TLZ39D-GS18 qualification status with the manufacturer is necessary prior to implementation in regulated automotive designs.

Frequently Asked Questions (FAQ)

Q: Can the TLZ39D-GS18 be used as a direct replacement for the VLZ39D-GS18 in existing designs?

A: The TLZ39D-GS18 is electrically compatible based on equivalent power dissipation (500 mW), impedance (85 Ohms maximum), and operating temperature range (-65°C to 175°C). The zener voltage difference of 1.42 V must be evaluated within the specific circuit application to confirm acceptable voltage regulation performance.

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

A: Both variants are classified within the SOD-80 package family and maintain compatible Surface Mount footprints. The QuadroMELF designation indicates a larger form factor, while MiniMELF represents a reduced-size variant. Physical dimensions and land pattern compatibility must be confirmed for PCB layout requirements.

Q: Why is the reverse leakage current specification different between the two parts?

A: The TLZ39D-GS18 specifies 40 nanoamperes (nA) reverse leakage current compared to 40 microamperes (µA) for the VLZ39D-GS18. This represents improved device performance in the substitute part, with lower leakage current indicating superior reverse-bias characteristics.

Q: Is the TLZ39D-GS18 suitable for automotive applications?

A: The TLZ39D-GS18 product status is listed as Active with no automotive grade or AEC-Q101 qualification specified in the provided parameters. Automotive application suitability requires confirmation of qualification status directly with Vishay General Semiconductor - Diodes Division.

Q: What is the inventory status of these components?

A: The VLZ39D-GS18 (obsolete) has 1019 pieces in stock. The TLZ39D-GS18 (active) has 1081 pieces in stock, providing reliable procurement availability for ongoing production requirements.

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