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onsemi BZX79C33_T50R
- Part No.:
- BZX79C33_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79C33_T50R.pdf
- Description:
- DIODE ZENER 33V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:5,411
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Product details
Overview
BZX79C33_T50R from ON Semiconductor is a 33 V, 5% tolerance, 500 mW DO-35 glass-encapsulated Zener diode optimized for voltage regulation and reference applications in power supply feedback loops, overvoltage protection circuits, and precision biasing networks.
For engineers reviewing the BZX79C33_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage (31 V to 35 V), dynamic impedance (80 Ω @ 2 mA), leakage current (≤0.05 μA @ 25.2 V), temperature coefficient (+25 mV/°C), and DO-35 package compatibility with through-hole PCB assembly.
Technical Context
The BZX79C33_T50R operates as a silicon planar Zener diode with sharp reverse breakdown at nominal 33 V, specified under thermal equilibrium at TL = 30°C ±1°C with 3/8″ lead length. Its design supports stable DC voltage reference generation in low-power analog circuits where tight tolerance and predictable TC are required.
It exhibits a positive temperature coefficient of +25 mV/°C above 6 V, enabling predictable drift compensation in temperature-sensitive references. Junction capacitance is 25 pF at VR = 0 V, f = 1 MHz, supporting moderate-frequency noise filtering in shunt regulator configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31 V to 35 V at IZ = 2 mA - defines regulated output range for shunt reference use |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous power handling in standard leaded mounting |
| Dynamic Impedance (ZZ) | 80 Ω max @ IZ = 2 mA - determines regulation stiffness and load transient response |
| Leakage Current (IR) | ≤0.05 μA @ VR = 25.2 V - ensures minimal error current in high-impedance reference nodes |
| Temperature Coefficient (TC) | +25 mV/°C - enables predictable voltage drift for temperature-compensated designs |
| Junction Capacitance (CJ) | 25 pF @ VR = 0 V, f = 1 MHz - impacts high-frequency noise rejection in filtering applications |
Pinout & Package
DO-35 glass axial package with cathode band marking; two-terminal device requiring no internal pin assignment beyond anode/cathode polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower potential node in reverse-biased Zener operation; carries forward current up to 100 mA |
| Cathode | Zener breakdown terminal | Connected to higher potential node; defines regulated voltage reference point at cathode-to-anode drop |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Ensures consistent regulation across production batches without post-assembly trimming |
| DO-35 glass package | Provides hermetic sealing and thermal stability for industrial ambient temperature operation (–65°C to +200°C) |
| Low leakage current | Maintains accuracy in high-impedance voltage divider and reference buffer circuits |
| Positive temperature coefficient | Enables predictable drift behavior for compensation in multi-Zener reference strings |
Applications
| Power Supply Feedback | Overvoltage Protection |
|---|---|
Use Scenario: Used in TL431-based adjustable SMPS feedback networks to set precise output voltage thresholds. IC Role / Device Role / Timing Role: Provides stable 33 V reference for optocoupler biasing and error amplifier input scaling. Use Value: Enables ±1% output regulation accuracy with minimal component count and no external calibration. | Use Scenario: Placed across sensitive IC inputs to clamp transients exceeding 35 V during ESD or surge events. IC Role / Device Role / Timing Role: Acts as passive shunt clamping element diverting excess energy to ground before damage occurs. Use Value: Limits peak voltage to 35 V with <0.05 μA standby leakage, preserving signal integrity in always-on monitoring circuits. |
| Precision Biasing | Reference Voltage Generation |
Use Scenario: Supplies fixed bias to op-amp input stages in instrumentation amplifiers operating from unregulated rails. IC Role / Device Role / Timing Role: Delivers low-drift, low-noise DC offset independent of supply variation. Use Value: Achieves <10 ppm/°C effective drift when combined with matched resistor networks due to +25 mV/°C TC predictability. | Use Scenario: Serves as primary reference in 12-bit ADC front-end circuits requiring stable 33 V excitation for ratiometric sensors. IC Role / Device Role / Timing Role: Functions as primary voltage reference source for sensor bridge excitation and DAC output scaling. Use Value: Maintains 33 V ±1.65 V regulation over –40°C to +85°C ambient, meeting industrial-grade accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A | 33 V, 5%, 1 W, DO-41 package, ZZ = 35 Ω @ 31 mA | Higher power rating but larger footprint and different thermal derating curve | Select when >500 mW dissipation or improved thermal margin is required |
| BZX55C33 | 33 V, 5%, 500 mW, DO-35, ZZ = 90 Ω @ 5 mA, TC = +25 mV/°C | Nearly identical electrical specs but slightly higher ZZ and different manufacturer qualification | Acceptable for drop-in replacement where ON Semi qualification is not mandatory |
Compared with BZX79C33_T50R, the 1N4749A offers higher power handling at the cost of larger DO-41 packaging and altered thermal behavior, while the BZX55C33 provides functionally equivalent regulation in the same DO-35 form factor with minor ZZ and test-current differences.
Availability
BZX79C33_T50R is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, and precision biasing applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for BZX79C33_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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud computing, medical, and IoT applications.
The BZX79C series was designed specifically for general-purpose voltage regulation and reference functions in cost-sensitive, high-volume consumer and industrial electronics using standardized DO-35 packaging.
FAQ
What is the nominal Zener voltage of the BZX79C33_T50R?
The BZX79C33_T50R has a nominal Zener voltage of 33 V, with a guaranteed range of 31 V to 35 V at test current IZ = 2 mA. This tolerance band reflects the 5% specification defined in the ON Semiconductor datasheet revision 3 (November 2017). The BZX79C33_T50R maintains this voltage under stable thermal conditions and is intended for use in shunt regulation topologies where precise DC reference is required.
What package type does the BZX79C33_T50R use?
The BZX79C33_T50R uses the DO-35 glass axial package, identifiable by its cylindrical glass body and cathode band marking. This package supports operating temperatures from –65°C to +200°C and is compatible with standard through-hole PCB assembly processes. The BZX79C33_T50R's DO-35 form factor ensures mechanical robustness and hermetic sealing for reliability in industrial environments.
What is the maximum power dissipation for the BZX79C33_T50R?
The BZX79C33_T50R has a maximum power dissipation of 500 mW at lead temperature TL ≤ 75°C with 3/8″ lead length. Above 75°C, it derates linearly at 4.0 mW/°C. This rating directly governs safe continuous operation in shunt regulator or clamping roles. Exceeding this limit risks thermal runaway or permanent degradation of the BZX79C33_T50R's Zener characteristics.
Does the BZX79C33_T50R have a positive or negative temperature coefficient?
The BZX79C33_T50R has a positive temperature coefficient of +25 mV/°C, consistent with Zener diodes rated above 6 V. This means its regulated voltage increases predictably with rising junction temperature. Designers can leverage this behavior for drift compensation in multi-diode reference strings. The BZX79C33_T50R's TC value is measured and specified per ON Semiconductor's characterization methodology in the official datasheet.
What is the typical dynamic impedance of the BZX79C33_T50R?
The BZX79C33_T50R has a maximum dynamic impedance (ZZ) of 80 Ω at IZ = 2 mA, as specified in the ON Semiconductor datasheet. This value reflects the slope of the Zener knee and determines how tightly the BZX79C33_T50R regulates against load or line variations. Lower ZZ improves regulation accuracy, and the BZX79C33_T50R's 80 Ω rating supports stable performance in medium-precision analog reference applications.
BZX79C33_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):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 23.1 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
BZX79C33_T50R FAQ
1.How can I place an order for BZX79C33_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79C33_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 BZX79C33_T50R reliable?
The price and inventory of BZX79C33_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79C33_T50R is usually 5 days.
3.What payment methods are accepted for BZX79C33_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79C33_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79C33_T50R?
BZX79C33_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79C33_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 BZX79C33_T50R?
For technical support, including BZX79C33_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79C33_T50R requirements.
6.How does Aetrix verify that BZX79C33_T50R is sourced from the original manufacturer or authorized distributors?
All BZX79C33_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 BZX79C33_T50R meets industry standards.
7.What is the process for return or replacement of BZX79C33_T50R?
All BZX79C33_T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX79C33_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 BZX79C33_T50R part is unused and in its original packaging.
Return procedure for BZX79C33_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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