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onsemi BZX85C39_T50A
- Part No.:
- BZX85C39_T50A
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
BZX85C39_T50A.pdf
- Description:
- DIODE ZENER 39V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:2,390
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Product details
Overview
BZX85C39_T50A from onsemi is a 39 V ±5% tolerance, 1.0 W axial-leaded Zener diode in DO-41 glass package, rated for 45 Ω zener impedance at 45 mA test current and 0.25 μA leakage current at 30.4 V reverse voltage, used for precision voltage regulation and overvoltage protection in power supply feedback loops.
For engineers reviewing the BZX85C39_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, power derating above 50°C (6.67 mW/°C), thermal stability across −65°C to +200°C, and DO-41 mechanical compatibility with through-hole PCB assembly.
Technical Context
The BZX85C39_T50A operates as a silicon planar Zener diode with controlled avalanche breakdown at 39 V nominal, specified under thermal equilibrium conditions at 30°C lead temperature and 3/8″ lead length. Its 1.0 W power rating at 25°C ambient is thermally limited by junction-to-lead resistance and glass-package heat dissipation characteristics.
Zener voltage is defined at IZ = 45 mA with VZ min = 37 V and max = 41 V; dynamic impedance (ZZ) is measured at this same current, while knee impedance (ZZK) is specified at IZK = 1 mA. Leakage current (IR) is guaranteed ≤0.25 μA at VR = 30.4 V - 78% of nominal VZ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 37 V to 41 V @ IZ = 45 mA - defines stable regulation range for feedback sensing |
| Power Dissipation (PD) | 1.0 W @ TA = 25°C - sets maximum continuous DC power handling before thermal shutdown |
| Zener Impedance (ZZ) | 6 Ω @ IZ = 45 mA - determines output voltage variation under load transients |
| Leakage Current (IR) | ≤0.25 μA @ VR = 30.4 V - ensures minimal quiescent current in standby mode |
| Tolerance | ±5% - enables predictable voltage reference accuracy without post-selection |
| Operating Temp Range | −65°C to +200°C - supports industrial and automotive under-hood applications |
| Derating Factor | 6.67 mW/°C above 50°C - required linear reduction in power capability for safe operation |
Pinout & Package
DO-41 glass axial package with cathode indicated by color band; leads are unmarked anode/cathode terminals suitable for through-hole mounting. Mechanical dimensions conform to JEDEC DO-204AL standard: body diameter 2.03–2.72 mm, overall length ≥25.40 mm, lead diameter 0.86–0.71 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unbanded end) | Forward conduction terminal | Connects to lower-potential node in reverse-biased regulation configuration |
| Cathode (banded end) | Zener breakdown terminal | Connects to higher-potential node; voltage referenced to this terminal during regulation |
Key Features
| Feature | Design Value |
|---|---|
| Stable Zener voltage with tight 5% tolerance | Enables single-device voltage reference without trimming in mid-range power supplies |
| Low dynamic impedance (6 Ω) | Minimizes output voltage deviation during 10–100 mA load steps in feedback networks |
| Hermetically sealed glass package | Ensures long-term parameter stability and moisture resistance in harsh environments |
| High-temperature operation up to +200°C | Supports placement near heat-generating components in enclosed industrial enclosures |
| Standard DO-41 footprint | Guarantees compatibility with legacy through-hole assembly lines and hand-soldering fixtures |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters via optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Precision voltage reference establishing error amplifier threshold. Use Value: 39 V nominal Zener voltage provides headroom for 24 V system clamping while maintaining margin against breakdown drift. |
Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 30 V. IC Role / Device Role / Timing Role: Shunt clamp limiting voltage excursion during ESD or inductive kick events. Use Value: 0.25 μA leakage at 30.4 V ensures negligible standby current draw while triggering reliably at 39 V. |
| Industrial Sensor Signal Conditioning | Programmable Logic Controller Input Protection |
Use Scenario: Biasing and level-shifting analog sensor outputs in 4–20 mA transmitter circuits. IC Role / Device Role / Timing Role: Stable reference for op-amp offset nulling and gain calibration. Use Value: ±5% tolerance and low ZZ enable <1% total error budget in 12-bit measurement systems. |
Use Scenario: Safeguarding PLC digital input stages against field-wiring faults and lightning-induced spikes. IC Role / Device Role / Timing Role: Primary shunt limiter in front-end protection network. Use Value: DO-41 glass construction withstands repeated 1 kW surge pulses per IEC 61000-4-5 without parameter shift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4739A | Same 39 V nominal, ±5% tolerance, but rated 1.0 W in DO-41 plastic package; ZZ = 9 Ω @ 45 mA | Lower moisture resistance and reduced high-temp reliability vs. glass DO-41 | Preferred for cost-sensitive consumer designs where extended temperature cycling is not required |
| BZX55C39 | 39 V, ±5%, 500 mW rating in DO-35 glass package; ZZ = 70 Ω @ 5 mA | Lower power handling and higher impedance limit use to low-current references | Selected when board space is constrained and regulation current remains below 10 mA |
Compared with BZX85C39_T50A, the 1N4739A offers identical voltage specs but trades glass hermeticity for plastic cost savings, while the BZX55C39 reduces size and power at the expense of regulation stiffness and thermal robustness - making BZX85C39_T50A optimal for industrial-grade 1 W reference needs.
Availability
BZX85C39_T50A is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor interfaces, and programmable logic controller input protection requiring stable component supply and long-term parametric consistency.
Supply support for BZX85C39_T50A 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 supplier specializing in energy-efficient power, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and IoT applications.
The BZX85C39_T50A belongs to the BZX85C series of general-purpose Zener diodes engineered for reliable voltage regulation and transient suppression in cost-sensitive yet thermally demanding industrial power systems.
FAQ
What is the maximum reverse voltage the BZX85C39_T50A can withstand before breakdown?
The BZX85C39_T50A has a nominal Zener voltage of 39 V with a guaranteed range of 37 V to 41 V at 45 mA test current. Its reverse breakdown is characterized at this point, and it is not rated for sustained operation above 41 V. The device exhibits sharp knee behavior starting near 37 V, making it unsuitable as a high-voltage blocking diode outside its regulated zone.
Does the BZX85C39_T50A have a specified forward voltage drop?
Yes - the BZX85C39_T50A specifies a maximum forward voltage (VF) of 1.2 V at 200 mA forward current. This value applies only when the diode is operated in forward bias; in normal Zener regulation use, the device remains reverse-biased, so VF is relevant only for polarity-check or fault-detection circuits.
Can the BZX85C39_T50A be used in surface-mount designs?
No - the BZX85C39_T50A uses a DO-41 axial glass package with 0.86–0.71 mm diameter leads intended for through-hole mounting. It lacks surface-mount terminations or tape-and-reel packaging. For SMT equivalents, consider the MMBZ5242B (39 V, SOD-123) or BZX84-C39 (SOT-23), which differ in power rating and impedance.
How does temperature affect the BZX85C39_T50A's Zener voltage?
The BZX85C39_T50A exhibits a positive temperature coefficient above ~5 V, meaning its Zener voltage increases with junction temperature. While the datasheet does not publish a TC value for BZX85C39_T50A specifically, typical 39 V Zeners in this family show +0.08%/°C to +0.12%/°C drift - resulting in ~±3% variation over −65°C to +150°C operating range.
Is the BZX85C39_T50A RoHS compliant and halogen-free?
Yes - the BZX85C39_T50A is manufactured by onsemi to meet RoHS Directive 2011/65/EU requirements and is halogen-free per J-STD-709 definition. Compliance is documented in onsemi's official material declarations and PB-free solderability reports, with lead-free termination and glass encapsulation ensuring full environmental conformance.
BZX85C39_T50A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Box (TB)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 45 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 27 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
BZX85C39_T50A FAQ
1.How can I place an order for BZX85C39_T50A through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX85C39_T50A 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 BZX85C39_T50A reliable?
The price and inventory of BZX85C39_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C39_T50A is usually 5 days.
3.What payment methods are accepted for BZX85C39_T50A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C39_T50A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX85C39_T50A?
BZX85C39_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX85C39_T50A 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 BZX85C39_T50A?
For technical support, including BZX85C39_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C39_T50A requirements.
6.How does Aetrix verify that BZX85C39_T50A is sourced from the original manufacturer or authorized distributors?
All BZX85C39_T50A 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 BZX85C39_T50A meets industry standards.
7.What is the process for return or replacement of BZX85C39_T50A?
All BZX85C39_T50A units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C39_T50A, 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 BZX85C39_T50A part is unused and in its original packaging.
Return procedure for BZX85C39_T50A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX85C39_T50A 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
-
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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