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onsemi BZX85C3V9TR
- Part No.:
- BZX85C3V9TR
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
BZX85C3V9TR.pdf
- Description:
- DIODE ZENER 3.9V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:6,343
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Product details
Overview
BZX85C3V9TR from onsemi is a 3.9 V, ±5% tolerance, 1.0 W axial-leaded Zener diode in DO-41 glass package, designed for voltage regulation and reference applications in power supply circuits, overvoltage protection, and signal conditioning. It exhibits 3.7 V minimum and 4.1 V maximum Zener voltage at 1 mA test current, 60 Ω dynamic impedance at 5 mA, and 5 μA maximum leakage current at 1 V reverse bias.
For engineers reviewing the BZX85C3V9TR datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance, power dissipation capability, thermal derating behavior, and DO-41 package compatibility with through-hole PCB assembly and manual rework workflows.
Technical Context
The BZX85C3V9TR operates as a silicon planar Zener diode optimized for stable voltage reference under reverse-biased conditions. Its 3.9 V nominal breakdown voltage is specified at 1 mA test current (IZ), with tight 5% tolerance and low dynamic impedance (60 Ω @ 5 mA) ensuring minimal output variation across load changes.
It supports continuous operation from –65 °C to +200 °C junction temperature, with 1.0 W power dissipation at 25 °C ambient and linear derating of 6.67 mW/°C above 50 °C - enabling reliable use in industrial power rails and automotive under-hood environments where thermal management is constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.7 V min / 4.1 V max @ IZ = 1 mA - defines usable regulation window for precision 3.9 V reference |
| Tolerance | ±5% - ensures predictable clamping level without post-selection or trimming |
| Power Dissipation (PD) | 1.0 W @ TA = 25°C - supports robust transient suppression in 5–12 V DC rails |
| Zener Impedance (ZZ) | 60 Ω @ IZ = 5 mA - limits output voltage shift under dynamic load steps |
| Leakage Current (IR) | 5 μA max @ VR = 1 V - guarantees low standby current in battery-backed circuits |
| Package | DO-41 glass axial - enables high-reliability hermetic sealing and standard wave-solder compatibility |
Pinout & Package
DO-41 glass axial package with cathode indicated by color band. Two-terminal device: anode and cathode only.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node during regulation; carries full load current in shunt configuration |
| Cathode | Zener breakdown terminal | Marked with color band; connected to higher-potential node; establishes regulated output voltage at cathode-to-ground |
Key Features
| Feature | Design Value |
|---|---|
| Stable Zener voltage at low test current | Specified at IZ = 1 mA - enables accurate regulation even in micro-power bias networks |
| Low dynamic impedance | 60 Ω @ 5 mA - maintains <±20 mV output deviation across typical load variations |
| Wide operating temperature range | –65 °C to +200 °C - suitable for under-hood automotive and industrial control enclosures |
| Hermetic glass encapsulation | DO-41 package per JEDEC DO-204AL - provides moisture resistance and long-term parameter stability |
Applications
| Power Supply Voltage Reference | Overvoltage Clamp Circuit |
|---|---|
Use Scenario: Providing stable 3.9 V reference for op-amp comparators and ADC biasing in isolated DC-DC converter feedback loops. IC Role / Device Role / Timing Role: Shunt voltage reference establishing precise threshold for error amplification. Use Value: ±5% tolerance and 60 Ω ZZ ensure reference drift remains below 0.2% over 0–50 mA load range. | Use Scenario: Protecting microcontroller I/O pins from ESD-induced transients on 5 V logic lines. IC Role / Device Role / Timing Role: Bidirectional transient suppressor clamping positive spikes to ~4.1 V and negative excursions to –0.7 V. Use Value: 1.0 W surge rating and 5 μA leakage allow safe operation without loading active circuitry during normal state. |
| Linear Regulator Feedback Divider | Current Source Bias Network |
Use Scenario: Setting output voltage in adjustable LDOs using resistor divider tied to BZX85C3V9TR cathode. IC Role / Device Role / Timing Role: Precision voltage node referenced to ground for feedback loop stability. Use Value: Low ZZ minimizes divider current dependency, improving line/load regulation accuracy by >0.15%. | Use Scenario: Generating constant bias current for LED drivers or transistor amplifiers via series resistor + BZX85C3V9TR. IC Role / Device Role / Timing Role: Fixed-voltage drop element enabling predictable current setpoint. Use Value: 3.7–4.1 V VZ range allows ±2% current accuracy with 1% resistors in 12 V supply configurations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4730A | 3.9 V nominal, ±5%, 1.0 W, DO-41 - identical VZ range but higher ZZ (100 Ω @ 5 mA) | Slightly reduced regulation accuracy under varying loads due to higher impedance | Acceptable where tighter voltage stability is not required; widely stocked legacy alternative |
| MMSZ4685 | 3.9 V nominal, ±5%, 500 mW, SOD-123 - surface-mount, lower power, higher ZZ (120 Ω @ 5 mA) | Not suitable for >0.5 W continuous dissipation; requires PCB redesign for SMT placement | Preferred for space-constrained designs where thermal budget permits lower power rating |
Compared with 1N4730A and MMSZ4685, the BZX85C3V9TR offers superior regulation stability (60 Ω vs. 100/120 Ω ZZ) and full 1.0 W capability in a through-hole package - making it optimal for legacy-compatible, thermally demanding, or serviceable power rail designs.
Availability
BZX85C3V9TR is available at Aetrix Electronics and suitable for power supply voltage reference, overvoltage clamp circuit, and linear regulator feedback divider applications requiring stable component supply and long-lifecycle support.
Supply support for BZX85C3V9TR 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
onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The BZX85C3V9TR belongs to the BZX85C series of general-purpose Zener diodes engineered for cost-effective, high-reliability voltage regulation in industrial power supplies and protection circuits.
FAQ
What is the Zener voltage tolerance of the BZX85C3V9TR?
The BZX85C3V9TR has a ±5% Zener voltage tolerance, meaning its actual breakdown voltage falls between 3.7 V and 4.1 V when measured at 1 mA test current and 25 °C ambient temperature. This tolerance is guaranteed across the full operating temperature range and is critical for applications requiring predictable clamping or reference levels without post-manufacturing calibration.
Can the BZX85C3V9TR be used in surface-mount designs?
No, the BZX85C3V9TR uses a DO-41 axial glass package intended for through-hole mounting. For surface-mount alternatives, consider the MMSZ4685 (SOD-123, 3.9 V, 500 mW) or NZ9F3V9T5G (SOD-923, 3.9 V, 200 mW). These require PCB layout changes and have different thermal and impedance characteristics compared to the BZX85C3V9TR.
What is the maximum power dissipation of the BZX85C3V9TR at 75 °C ambient?
At 75 °C ambient, the BZX85C3V9TR's power dissipation must be derated from its 1.0 W rating at 25 °C. With a derating factor of 6.67 mW/°C above 50 °C, the allowable power is 1.0 W − (25 °C × 6.67 mW/°C) = 833 mW. This ensures junction temperature remains within the –65 °C to +200 °C safe operating range.
How does the BZX85C3V9TR compare to the BZX85C3V3 in terms of leakage current?
The BZX85C3V9TR specifies 5 μA maximum leakage current at 1 V reverse bias, whereas the BZX85C3V3 specifies 60 μA under the same condition. This 12× lower leakage makes the BZX85C3V9TR more suitable for low-power and battery-sensitive applications where standby current must be minimized.
Is forward voltage specified for the BZX85C3V9TR?
Yes - the BZX85C3V9TR has a maximum forward voltage (VF) of 1.2 V at 200 mA forward current, consistent with standard silicon diode behavior. This value is relevant for polarity-check circuits or applications where the device may conduct in forward bias during fault conditions.
BZX85C3V9TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 3.9 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 15 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
BZX85C3V9TR FAQ
1.How can I place an order for BZX85C3V9TR through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX85C3V9TR 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 BZX85C3V9TR reliable?
The price and inventory of BZX85C3V9TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C3V9TR is usually 5 days.
3.What payment methods are accepted for BZX85C3V9TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C3V9TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX85C3V9TR?
BZX85C3V9TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX85C3V9TR 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 BZX85C3V9TR?
For technical support, including BZX85C3V9TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C3V9TR requirements.
6.How does Aetrix verify that BZX85C3V9TR is sourced from the original manufacturer or authorized distributors?
All BZX85C3V9TR 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 BZX85C3V9TR meets industry standards.
7.What is the process for return or replacement of BZX85C3V9TR?
All BZX85C3V9TR units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C3V9TR, 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 BZX85C3V9TR part is unused and in its original packaging.
Return procedure for BZX85C3V9TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX85C3V9TR Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZT52C15-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
onsemi
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SMAJ4744A-TP
Micro Commercial Co
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BZT52C3V6LP-7
Diodes Incorporated
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SMAZ12-13-F
Diodes Incorporated
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