FLZ18VB Zener Diode Equivalent & Substitute Parts

Part Overview

The FLZ18VB is a 17.3 V, 500 mW Zener diode manufactured by onsemi in SOD-80 surface mount packaging. This component is classified as obsolete, necessitating identification of active equivalent parts for ongoing design requirements and production continuity. The FLZ18VB serves as a voltage regulation and protection element in electronic circuits requiring precise Zener voltage characteristics at moderate power dissipation levels.

Substiute Parts

FLZ18VB

onsemiIn Stock: 789FLZ18VB Datasheet

Current PartRFQ

BZV55-C18,115

NXP SemiconductorsIn Stock: 25782BZV55-C18,115 Datasheet

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BZV55-C18,135

Nexperia USA Inc.In Stock: 12807BZV55-C18,135 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FLZ18VB is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Zener voltage nominal value within acceptable circuit tolerance
• Maximum power dissipation rating equal to or greater than 500 mW
• Impedance characteristics suitable for the application circuit
• Reverse leakage current specifications compatible with circuit requirements
• Forward voltage characteristics within acceptable operating ranges
• Operating temperature range encompassing the FLZ18VB range (-65°C to 175°C)

Mechanical Compatibility Criteria:

• Surface mount packaging format (SOD-80 / DO-213AC / MINI-MELF)
• Physical dimensions compatible with existing PCB layouts

The substitute parts identified (BZV55-C18,115 and BZV55-C18,135) share identical power ratings, equivalent packaging, and overlapping operating temperature ranges. Both substitute parts operate at 18 V nominal Zener voltage, representing a 0.7 V differential from the FLZ18VB. This voltage differential must be evaluated within the specific circuit application to determine functional equivalence.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The FLZ18VB is classified as obsolete. Both substitute parts (BZV55-C18,115 and BZV55-C18,135) maintain active product status, ensuring long-term availability and continued manufacturer support.

Compliance and Certification: All three parts carry REACH Unaffected status and EAR99 ECCN classification, indicating equivalent regulatory compliance. The BZV55-C18,135 variant includes RoHS3 compliance certification.

Electrical Parameter Differences: The substitute parts operate at 18 V nominal Zener voltage compared to the FLZ18VB's 17.3 V. This 0.7 V difference represents approximately 4% variance. Circuit applications with strict voltage regulation requirements must evaluate this differential against design tolerances. The substitute parts exhibit higher impedance (45 Ohms versus 19.4 Ohms) and lower reverse leakage current (50 nA versus 133 nA), characteristics that may improve circuit performance in certain applications.

Temperature Range: The substitute parts extend the upper operating temperature limit to 200°C, providing enhanced thermal margin beyond the FLZ18VB's 175°C maximum.

Packaging and Inventory: Both substitute parts are available in equivalent SOD-80 surface mount packaging with significantly higher inventory levels (25,760 and 12,711 units respectively) compared to the FLZ18VB's 704 units.

Frequently Asked Questions (FAQ)

Q: Can BZV55-C18,115 and BZV55-C18,135 be used interchangeably with FLZ18VB?

A: Both parts share identical electrical ratings (500 mW power, surface mount packaging) and equivalent package dimensions. The primary consideration is the 0.7 V nominal Zener voltage difference (18 V versus 17.3 V). Interchangeability depends on circuit tolerance specifications. Applications requiring precise 17.3 V regulation may require circuit redesign or voltage divider adjustment.

Q: What is the difference between BZV55-C18,115 and BZV55-C18,135?

A: Both parts are electrically identical with matching Zener voltage (18 V), power rating (500 mW), impedance (45 Ohms), and operating temperature range (-65 to 200°C). The primary difference is packaging format: BZV55-C18,115 is supplied in standard packaging, while BZV55-C18,135 is available in Cut Tape (CT) and Digi-Reel® formats. Selection depends on procurement and assembly requirements.

Q: Are the substitute parts compatible with existing PCB layouts designed for FLZ18VB?

A: Yes. All three parts utilize identical SOD-80 / DO-213AC / MINI-MELF surface mount packaging with equivalent physical dimensions and pin configurations. Direct PCB layout compatibility is maintained.

Q: How does the impedance difference affect circuit performance?

A: The FLZ18VB exhibits lower impedance (19.4 Ohms) compared to the substitute parts (45 Ohms). Lower impedance provides better voltage regulation stability under load variations. Applications sensitive to impedance characteristics should evaluate this parameter against specific circuit requirements.

Q: What is the significance of the tolerance difference (±3% versus ±5%)?

A: The FLZ18VB maintains tighter Zener voltage tolerance (±3%) compared to the substitute parts (±5%). Applications requiring precise voltage regulation within narrow bands should account for this tolerance variance in circuit design calculations.

Q: Do the substitute parts meet the same regulatory requirements as FLZ18VB?

A: Yes. All parts carry REACH Unaffected status and EAR99 ECCN classification. The BZV55-C18,135 additionally includes RoHS3 compliance certification, providing enhanced regulatory coverage for certain markets and applications.

Q: What is the reverse leakage current significance?

A: The substitute parts exhibit lower reverse leakage current (50 nA @ 12.6 V) compared to FLZ18VB (133 nA @ 13 V). Lower leakage current reduces parasitic current paths and improves circuit efficiency in applications where reverse bias conditions are present.