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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Vishay General Semiconductor - Diodes Division BZX55B3V9-TAP

Name: BZX55B3V9-TAP
Brand: Vishay General Semiconductor - Diodes Division
SKU: BZX55B3V9-TAP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX55B3V9-TAP

Manufacturer:: Vishay General Semiconductor - Diodes Division

Category:: Single Zener Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: BZX55B3V9-TAP.pdf

Description:: DIODE ZENER 3.9V 500MW DO204AH

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Product details

Overview

BZX55B3V9-TAP from Vishay Semiconductors is a precision 3.9 V Zener diode in DO-35 (DO-204AH) package, designed for voltage regulation and reference applications with ±1% nominal tolerance, 5 mA test current, and <2 μA reverse leakage at 1 V. It delivers stable clamping in low-power analog circuits, power supply feedback loops, and overvoltage protection stages.

For engineers reviewing the BZX55B3V9-TAP datasheet, BZX55B3V9-TAP pinout, BZX55B3V9-TAP application, or BZX55B3V9-TAP equivalent, key selection criteria include its tight 3.82–3.98 V zener voltage range at 5 mA, 90 Ω dynamic resistance, -0.08%/K temperature coefficient at 25 °C, and DO-35 package compatibility with through-hole PCB layouts.

Technical Context

The BZX55B3V9-TAP operates as a single-element, silicon planar Zener diode optimized for sharp reverse breakdown and low noise. Its design targets stable DC voltage reference generation under low-current conditions (IZT = 5 mA), with guaranteed performance across -65 °C to +175 °C storage and 150 °C junction operation.

It features a maximum power dissipation of 500 mW at TL = 25 °C with 4 mm lead length, thermal resistance of 300 K/W, and forward voltage ≤1.5 V at 200 mA - enabling reliable use in biasing, sensing, and trimming circuits where precision and long-term stability are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	3.82–3.98 V at I_ZT = 5 mA - ensures tight regulation window for 3.3 V and 5 V rail monitoring
Dynamic Resistance (Z_Z)	<90 Ω at 5 mA - minimizes output voltage variation under load transients
Reverse Leakage Current	<2 μA at V_R = 1 V - preserves low quiescent current in battery-powered references
Temperature Coefficient	-0.08 %/K at 25 °C - enables predictable drift compensation in temperature-sensitive analog designs
Power Dissipation	500 mW - supports continuous operation in ambient temperatures up to 70 °C without derating
Junction Temperature	175 °C max - allows deployment in industrial and automotive under-hood environments
Package	DO-35 (DO-204AH) - standard through-hole glass-passivated package with cathode band marking

Pinout & Package

DO-35 (DO-204AH) package: axial-leaded, glass-encapsulated, cathode identified by painted band. Total weight ≈125 mg; UL 94 V-0 molding compound; MSL Level 1 per J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / reference ground node	Connected to circuit common or lower-potential side in shunt regulator configuration
Cathode	Zener breakdown terminal / regulated output node	Provides stable 3.9 V reference when reverse-biased; marked with band on DO-35 body

Key Features

Feature	Design Value
Very sharp reverse characteristic	Enables precise, low-hysteresis voltage clamping at 3.9 V with minimal knee voltage spread
Low reverse current level	<2 μA at 1 V reverse bias reduces loading error in high-impedance reference dividers
Very high stability	Guaranteed long-term V_Z drift <±1% after 1000 hrs at rated power supports calibration-critical systems
Low noise	Minimal avalanche-induced broadband noise ideal for precision ADC reference buffers and sensor signal conditioning
Material compliance	Meets Vishay's material categorization per doc#99912 - RoHS-compliant, halogen-free construction

Applications

Industrial Sensor Signal Conditioning	Microcontroller Power Supply Monitoring
Use Scenario: Stabilizing reference voltage for bridge sensor amplifiers in pressure or temperature transmitters. IC Role / Device Role / Timing Role: Shunt voltage reference providing fixed 3.9 V bias to op-amp input stages and ADC reference inputs. Use Value: Tight ±1% V_Z tolerance and low TC ensure measurement accuracy remains within 0.1% over -40 °C to +85 °C operating range.	Use Scenario: Detecting brown-out conditions on 3.3 V MCU supply rails using comparator-based reset circuitry. IC Role / Device Role / Timing Role: Zener-clamped threshold element defining reset trigger point at ~3.9 V. Use Value: Sharp reverse knee and low leakage allow clean, repeatable trip points without external hysteresis components.
Low-Power Battery Voltage Regulation	Overvoltage Protection Clamping
Use Scenario: Regulating auxiliary 3.9 V rail for real-time clock (RTC) backup in coin-cell powered devices. IC Role / Device Role / Timing Role: Passive shunt regulator maintaining stable RTC supply despite varying battery voltage (2.0–3.6 V). Use Value: 500 mW rating and 175 °C T_j enable safe operation even during extended storage at elevated temperatures.	Use Scenario: Protecting analog front-end inputs from ESD or transient surges exceeding 5 V. IC Role / Device Role / Timing Role: Fast-acting clamp limiting input voltage to 3.9 V + diode forward drop during fault events. Use Value: Low dynamic resistance (<90 Ω) and fast response minimize clamping overshoot and protect downstream ICs.

Industrial Sensor Signal Conditioning

Microcontroller Power Supply Monitoring

Use Scenario: Stabilizing reference voltage for bridge sensor amplifiers in pressure or temperature transmitters.

IC Role / Device Role / Timing Role: Shunt voltage reference providing fixed 3.9 V bias to op-amp input stages and ADC reference inputs.

Use Value: Tight ±1% V_Z tolerance and low TC ensure measurement accuracy remains within 0.1% over -40 °C to +85 °C operating range.

Use Scenario: Detecting brown-out conditions on 3.3 V MCU supply rails using comparator-based reset circuitry.

IC Role / Device Role / Timing Role: Zener-clamped threshold element defining reset trigger point at ~3.9 V.

Use Value: Sharp reverse knee and low leakage allow clean, repeatable trip points without external hysteresis components.

Low-Power Battery Voltage Regulation

Overvoltage Protection Clamping

Use Scenario: Regulating auxiliary 3.9 V rail for real-time clock (RTC) backup in coin-cell powered devices.

IC Role / Device Role / Timing Role: Passive shunt regulator maintaining stable RTC supply despite varying battery voltage (2.0–3.6 V).

Use Value: 500 mW rating and 175 °C T_j enable safe operation even during extended storage at elevated temperatures.

Use Scenario: Protecting analog front-end inputs from ESD or transient surges exceeding 5 V.

IC Role / Device Role / Timing Role: Fast-acting clamp limiting input voltage to 3.9 V + diode forward drop during fault events.

Use Value: Low dynamic resistance (<90 Ω) and fast response minimize clamping overshoot and protect downstream ICs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode voltage reference applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4729A-TAP	3.6 V nominal, ±5% tolerance, 10 mA test current, higher Z_Z (~10 Ω)	Looser regulation accuracy; better suited for non-critical biasing than precision references	Select only if 3.6 V target and wider tolerance are acceptable; not drop-in for 3.9 V designs
BZX55C3V9-TAP	Same 3.9 V nominal but ±5% tolerance (3.7–4.1 V), higher IR (<2 μA same), identical DO-35 package	Lower cost option where ±5% V_Z meets system requirements	Valid alternative if design tolerates wider voltage window; shares footprint and soldering profile

Compared with BZX55B3V9-TAP, the 1N4729A-TAP offers lower precision but higher test current headroom, while BZX55C3V9-TAP provides identical packaging and basic functionality at reduced accuracy - making it suitable for cost-sensitive, non-critical regulation tasks where 3.9 V nominal is retained.

Availability

BZX55B3V9-TAP is available at Aetrix Electronics and suitable for industrial sensor interfaces, microcontroller power monitoring, and low-power battery regulation requiring stable component supply, consistent parametric performance, and long-lifecycle availability.

Supply support for BZX55B3V9-TAP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Vishay Semiconductors is a global leader in discrete semiconductors, specializing in high-reliability diodes, MOSFETs, optoelectronics, and passive components for industrial, automotive, and computing markets.

The BZX55-Series is part of Vishay's precision Zener portfolio, engineered for voltage stabilization in analog signal chains, power supply feedback, and reference applications demanding tight tolerance, low noise, and thermal stability.

FAQ

What is the exact zener voltage range for BZX55B3V9-TAP at 5 mA test current?

The BZX55B3V9-TAP has a guaranteed zener voltage range of 3.82 V to 3.98 V when tested at I_ZT = 5 mA and T_amb = 25 °C. This ±1% tolerance reflects its "B" grade precision binning, distinguishing it from the looser ±5% "C" grade variants like BZX55C3V9-TAP.

Is BZX55B3V9-TAP compatible with lead-free reflow soldering processes?

Yes, BZX55B3V9-TAP is qualified for lead-free soldering with a peak temperature limit of 260 °C per J-STD-020, matching standard Pb-free reflow profiles. Its DO-35 package uses UL 94 V-0 compliant molding compound and carries MSL Level 1 rating - no dry-pack or bake required before assembly.

Can BZX55B3V9-TAP be used in series or parallel configurations?

BZX55B3V9-TAP is specified for single-diode shunt operation. Series connection is possible for higher reference voltages but requires matched units to avoid current imbalance; parallel use is not recommended due to inherent V_Z tolerance and thermal runaway risk without ballasting resistors.

What is the maximum allowable reverse voltage before breakdown for BZX55B3V9-TAP?

The BZX55B3V9-TAP begins controlled zener breakdown at its specified V_Z range (3.82–3.98 V). Its absolute maximum reverse voltage is not defined separately - operation above V_Z must remain within P_tot = 500 mW limits. Reverse voltage below V_Z (e.g., 1 V) yields <2 μA leakage, per datasheet test condition.

Does BZX55B3V9-TAP have a specified capacitance value?

While the BZX55-Series datasheet does not list a specific capacitance for BZX55B3V9-TAP, Figure 5 shows typical diode capacitance vs. zener voltage: at V_R = 2 V, C_D ≈ 15–20 pF for 3.9 V devices. This low capacitance supports use in high-frequency noise filtering and RF decoupling applications without signal degradation.

BZX55B3V9-TAP Specifications

Product attributes: Attribute value

Manufacturer:: Vishay General Semiconductor - Diodes Division

Series:: BZX55

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Cut Tape (CT)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 3.9 V

Tolerance:: ±2%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 90 Ohms

Current - Reverse Leakage @ Vr:: 2 µA @ 1 V

Voltage - Forward (Vf) (Max) @ If:: 1.5 V @ 200 mA

Operating Temperature:: -65°C ~ 175°C

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Through Hole

Supplier Device Package:: DO-204AH (DO-35)

BZX55B3V9-TAP FAQ

1.How can I place an order for BZX55B3V9-TAP through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX55B3V9-TAP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BZX55B3V9-TAP reliable?

The price and inventory of BZX55B3V9-TAP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX55B3V9-TAP is usually 5 days.

3.What payment methods are accepted for BZX55B3V9-TAP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX55B3V9-TAP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX55B3V9-TAP?

BZX55B3V9-TAP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX55B3V9-TAP order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BZX55B3V9-TAP?

For technical support, including BZX55B3V9-TAP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX55B3V9-TAP requirements.

6.How does Aetrix verify that BZX55B3V9-TAP is sourced from the original manufacturer or authorized distributors?

All BZX55B3V9-TAP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BZX55B3V9-TAP meets industry standards.

7.What is the process for return or replacement of BZX55B3V9-TAP?

All BZX55B3V9-TAP units undergo pre-shipment inspection (PSI). If there is an issue with BZX55B3V9-TAP, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BZX55B3V9-TAP part is unused and in its original packaging.

Return procedure for BZX55B3V9-TAP:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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