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onsemi BZX79C12_T50R
- Part No.:
- BZX79C12_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79C12_T50R.pdf
- Description:
- DIODE ZENER 12V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:4,132
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Product details
Overview
BZX79C12_T50R from ON Semiconductor is a 12 V, 5% tolerance, 500 mW DO-35 glass-case Zener diode optimized for voltage regulation and reference applications in low-power analog circuits, power supply feedback loops, and overvoltage protection stages.
For engineers reviewing the BZX79C12_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy at 5 mA test current, 25 Ω dynamic impedance, ±0.1 μA leakage at 9.2 V, temperature coefficient of +6 mV/°C, and DO-35 package compatibility with through-hole PCB assembly.
Technical Context
This discrete Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load and input conditions. It is characterized at 5 mA nominal zener test current (IZ), with a specified zener voltage range of 11.4 V to 12.7 V and a maximum dynamic impedance (ZZ) of 25 Ω at IZ = 5 mA.
The device exhibits a positive temperature coefficient of +6 mV/°C, indicating increasing zener voltage with rising junction temperature, and supports operation from –65 °C to +200 °C. Its 500 mW power dissipation rating is derated linearly above 75 °C at 4.0 mW/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 11.4 V min to 12.7 V max at IZ = 5 mA - defines regulated output voltage window under nominal bias |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous thermal load in standard lead-length mounting |
| Dynamic Impedance (ZZ) | 25 Ω max at IZ = 5 mA - determines regulation stiffness and output voltage variation under load changes |
| Leakage Current (IR) | 0.1 μA max at VR = 9.2 V - ensures minimal parasitic current in off-state or standby modes |
| Temperature Coefficient (TC) | +6 mV/°C - quantifies voltage drift per degree rise, critical for precision references over temperature |
| Junction Capacitance (C) | 55 pF max at VZ = 0, f = 1 MHz - impacts high-frequency noise filtering and transient response |
Pinout & Package
DO-35 glass axial package with cathode indicated by a color band on the body; two-terminal device requiring no external biasing circuitry beyond series current-limiting resistor.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reverse-biased input terminal | Connected to lower-potential node; carries forward current during non-regulation states |
| Cathode | Zener output / regulated voltage node | Provides stable 12 V reference when reverse-biased above breakdown; marked with color band |
Key Features
| Feature | Design Value |
|---|---|
| ±5% zener voltage tolerance | Ensures predictable regulation window without post-manufacture trimming in cost-sensitive designs |
| DO-35 glass package | Enables reliable high-temperature operation up to +200 °C and compatibility with legacy through-hole assembly lines |
| Low leakage current | 0.1 μA max at 9.2 V enables use in battery-powered or ultra-low-quiescent-current circuits |
| Stable TC over operating range | +6 mV/°C allows accurate compensation in temperature-critical reference designs |
Applications
| Power Supply Feedback | Overvoltage Clamp |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback or buck-derived DC-DC converters via optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Zener reference element setting precise error amplifier threshold in secondary-side control circuitry. Use Value: Maintains ±5% output regulation accuracy across line/load/temperature with 25 Ω dynamic impedance limiting feedback error. | Use Scenario: Protecting microcontroller I/O pins or ADC inputs from transient overvoltage events exceeding 12 V. IC Role / Device Role / Timing Role: Shunt clamping device diverting excess current when input exceeds 12.7 V breakdown threshold. Use Value: Limits peak voltage to ≤12.7 V with <0.1 μA leakage below 9.2 V, preserving signal integrity in normal operation. |
| Voltage Reference | Signal Level Translation |
Use Scenario: Providing stable 12 V reference for analog comparators, DAC buffers, or sensor excitation circuits. IC Role / Device Role / Timing Role: Precision voltage source establishing known bias point independent of supply fluctuations. Use Value: Delivers 11.4–12.7 V with +6 mV/°C TC, enabling <±1% drift over –40 to +85 °C industrial range. | Use Scenario: Biasing level-shifting networks between 15 V logic and 12 V analog subsystems in mixed-signal boards. IC Role / Device Role / Timing Role: Clamped reference node defining upper rail for resistive divider-based translation. Use Value: Fixes translation threshold at 12 V with 500 mW dissipation handling brief surge currents without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4742A | Same 12 V nominal rating, 1 W power rating, DO-41 package, ±5% tolerance, 22 Ω ZZ | Higher power handling but larger footprint; requires layout change for DO-41 vs DO-35 | Select when >500 mW dissipation or higher surge immunity is required |
| MMSZ4685 | 12 V SOD-123 surface-mount package, 500 mW, ±5%, 30 Ω ZZ, 0.1 μA IR | Replaces through-hole with SMT; not pin-compatible; requires rework of PCB assembly process | Select for space-constrained or automated SMT production environments |
Compared with 1N4742A and MMSZ4685, BZX79C12_T50R offers identical voltage tolerance and leakage performance in a legacy-compatible DO-35 through-hole package, making it optimal for repair, prototyping, and industrial systems where mechanical robustness and thermal stability up to +200 °C are prioritized over power or density.
Availability
BZX79C12_T50R is available at Aetrix Electronics and suitable for power supply feedback, overvoltage clamp, and voltage reference applications requiring stable component supply, long-lifecycle support, and consistent parametric performance across manufacturing lots.
Supply support for BZX79C12_T50R 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
ON Semiconductor (now onsemi) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The BZX79C series was designed specifically for general-purpose voltage regulation and reference functions in cost-sensitive, thermally demanding applications where DO-35 reliability and wide temperature range are essential.
FAQ
What is the nominal zener voltage of BZX79C12_T50R and how is it tested?
The BZX79C12_T50R has a nominal zener voltage of 12 V, with a guaranteed range of 11.4 V to 12.7 V at a test current of 5 mA and lead temperature of 30 °C ± 1 °C. This specification is verified per ON Semiconductor's BZX79C2V4–BZX79C56 datasheet Rev. 3, using standardized thermal equilibrium conditions and 3/8" lead length.
Does BZX79C12_T50R have polarity markings, and how is the cathode identified?
Yes, BZX79C12_T50R uses a color band on the glass body to denote the cathode terminal. Per the official datasheet, this marking is mandatory and aligns with industry-standard DO-35 polarity conventions - the banded end connects to the higher-potential node in reverse-bias regulation configurations.
What is the maximum power dissipation for BZX79C12_T50R and how does it change with temperature?
BZX79C12_T50R is rated for 500 mW maximum power dissipation at lead temperature (TL) ≤ 75 °C. Above that temperature, it must be derated linearly at 4.0 mW/°C - for example, at TL = 100 °C, allowable PD drops to 400 mW. This derating ensures safe junction temperature operation within the –65 °C to +200 °C storage range.
How does the temperature coefficient of BZX79C12_T50R affect its regulation accuracy?
The BZX79C12_T50R has a positive temperature coefficient of +6 mV/°C, meaning its zener voltage increases by approximately 6 mV per degree Celsius rise in junction temperature. This behavior must be factored into precision reference designs - for instance, over a 100 °C span, voltage shift may reach ±0.6 V, requiring compensation or system-level calibration if sub-1% stability is needed.
Is BZX79C12_T50R suitable for use in high-reliability industrial environments?
Yes, BZX79C12_T50R is qualified for industrial use with an operating temperature range of –65 °C to +200 °C and DO-35 glass construction offering superior hermeticity and thermal cycling resistance. Its 500 mW rating, low leakage (<0.1 μA), and stable +6 mV/°C TC make it appropriate for motor drives, PLC I/O modules, and power metering systems exposed to harsh thermal profiles.
BZX79C12_T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 12 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 25 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 8 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 100 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
BZX79C12_T50R FAQ
1.How can I place an order for BZX79C12_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79C12_T50R 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 BZX79C12_T50R reliable?
The price and inventory of BZX79C12_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79C12_T50R is usually 5 days.
3.What payment methods are accepted for BZX79C12_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79C12_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79C12_T50R?
BZX79C12_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79C12_T50R 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 BZX79C12_T50R?
For technical support, including BZX79C12_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79C12_T50R requirements.
6.How does Aetrix verify that BZX79C12_T50R is sourced from the original manufacturer or authorized distributors?
All BZX79C12_T50R 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 BZX79C12_T50R meets industry standards.
7.What is the process for return or replacement of BZX79C12_T50R?
All BZX79C12_T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX79C12_T50R, 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 BZX79C12_T50R part is unused and in its original packaging.
Return procedure for BZX79C12_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX79C12_T50R Tags
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Diodes Incorporated
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