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onsemi BZX55C43_T50R
- Part No.:
- BZX55C43_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX55C43_T50R.pdf
- Description:
- DIODE ZENER 43V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:9,139
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Product details
Overview
BZX55C43_T50R from Fairchild Semiconductor is a 43 V ±5% tolerance Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C with 4.0 mW/°C derating, 90 Ω dynamic impedance at 2.5 mA test current, and 0.1 μA maximum reverse leakage at 32 V. It provides precision voltage regulation in low-power reference and protection circuits.
For engineers reviewing the BZX55C43_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, dynamic impedance at nominal test current, reverse leakage at rated VR, and DO-35 mechanical compatibility in space-constrained analog designs.
Technical Context
The BZX55C43_T50R operates as a silicon planar Zener diode optimized for stable voltage reference and overvoltage clamping. Its 43 V nominal breakdown voltage is specified at 2.5 mA test current with ±5% tolerance, and it maintains regulation across -65°C to +200°C operating and storage temperature range.
It exhibits 90 Ω dynamic impedance (ZZ) at IZ = 2.5 mA, 0.1 μA maximum reverse leakage current (IR) at VR = 32 V, and supports up to 9.2 mA maximum zener current (IZM) under worst-case thermal conditions per the power derating curve.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 43 V nominal, ±5% tolerance - defines precise clamping/reference point in feedback or protection paths |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous power handling before thermal derating applies |
| Dynamic Impedance (ZZ) | 90 Ω @ IZ = 2.5 mA - determines voltage regulation stability under varying load currents |
| Reverse Leakage (IR) | ≤ 0.1 μA @ VR = 32 V - ensures minimal standby current in high-impedance bias networks |
| Max Zener Current (IZM) | 9.2 mA - derived from VZ and derated PD; limits peak surge capability without exceeding junction limits |
| Operating Temp Range | -65°C to +200°C - enables use in automotive under-hood, industrial, and aerospace environments |
Pinout & Package
DO-35 glass axial package with cathode band marking; two-terminal device requiring no PCB footprint redesign when replacing other DO-35 Zeners.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration |
| Cathode | Zener breakdown terminal | Marked with color band; connected to higher-potential node for voltage reference or clamping |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables tight regulation without post-production trimming in cost-sensitive references |
| DO-35 glass package | Provides hermetic sealing and proven reliability in high-temp/humidity environments |
| 90 Ω dynamic impedance | Minimizes output voltage variation across 1–5 mA load current changes in shunt regulators |
| 0.1 μA reverse leakage @ 32 V | Preserves signal integrity in high-Z sensor biasing and precision op-amp reference networks |
Applications
| Power Supply Feedback | Overvoltage Protection |
|---|---|
Use Scenario: Shunt regulator in isolated flyback auxiliary winding feedback path. IC Role / Device Role / Timing Role: Zener reference for TL431 or optocoupler biasing to regulate output voltage. Use Value: 43 V rating allows direct sensing of 36–40 V auxiliary rails without resistor divider scaling. | Use Scenario: Clamping circuit on microcontroller I/O line exposed to transient surges. IC Role / Device Role / Timing Role: Fast-acting voltage limiter protecting GPIO against ESD or inductive kick. Use Value: 90 Ω ZZ and low IR ensure rapid response and negligible loading during normal operation. |
| Temperature-Stable Reference | Industrial Sensor Biasing |
Use Scenario: Precision voltage reference for RTD or thermistor measurement bridges. IC Role / Device Role / Timing Role: Stable DC reference source compensating for amplifier offset drift. Use Value: -65°C to +200°C operating range supports calibration stability across extended thermal cycles. | Use Scenario: High-impedance bias network for piezoresistive pressure sensors. IC Role / Device Role / Timing Role: Low-leakage voltage source establishing sensor excitation potential. Use Value: 0.1 μA IR at 32 V prevents measurement error in nanoamp-level bridge currents. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A | Same 43 V nominal, but ±5% tolerance and 100 Ω ZZ @ 13 mA - higher test current shifts operating point | Designed for higher-current shunt regulation; less suitable for low-IZ bias networks | Select BZX55C43_T50R when operating near 2.5 mA or requiring tighter thermal coefficient matching |
| MMBZ5257B | SOT-23 surface-mount package; same 43 V, ±5%, but 100 Ω ZZ @ 20 mA and 0.1 μA IR @ 34 V | Requires PCB rework for replacement; better suited for automated assembly than through-hole DO-35 | Choose BZX55C43_T50R for legacy through-hole designs or where DO-35 mechanical robustness is prioritized |
Compared with 1N4749A and MMBZ5257B, the BZX55C43_T50R offers optimal balance of low-test-current impedance, DO-35 mechanical reliability, and wide temperature support - making it preferred for analog reference and protection circuits where thermal stability and legacy compatibility matter.
Availability
BZX55C43_T50R is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, temperature-stable reference, and industrial sensor biasing requiring stable component supply across long-lifecycle industrial programs.
Supply support for BZX55C43_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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.
The BZX55 series belongs to Fairchild's general-purpose Zener diode product line, designed for cost-effective, reliable voltage regulation and transient suppression in consumer, industrial, and computing power systems.
FAQ
What is the zener voltage tolerance of BZX55C43_T50R?
The BZX55C43_T50R has a nominal zener voltage of 43 V with a guaranteed tolerance of ±5%, meaning the actual breakdown voltage falls between 40.85 V and 45.15 V at 2.5 mA test current and 25°C. This tolerance is confirmed in the Fairchild BZX55C2V4–BZX55C56 datasheet Rev. D1, and applies directly to the BZX55C43_T50R variant. The tolerance remains valid across the full operating temperature range.
What is the maximum power dissipation for BZX55C43_T50R?
The BZX55C43_T50R is rated for 500 mW power dissipation at lead temperature (TL) ≤ 75°C with 3/8" lead length. Above 75°C, it derates linearly at 4.0 mW/°C. This limit is defined in the Absolute Maximum Ratings table of the official datasheet and reflects safe continuous operation without junction overheating. Exceeding this requires thermal modeling or forced cooling.
What is the dynamic impedance of BZX55C43_T50R and why does it matter?
The BZX55C43_T50R has a dynamic impedance (ZZ) of 90 Ω measured at 2.5 mA test current. This value quantifies how much the zener voltage changes per unit change in current - critical for maintaining regulation accuracy in shunt references. Lower ZZ improves load regulation; 90 Ω is typical for 43 V Zeners in the BZX55C family and is verified in the Electrical Characteristics table.
Does BZX55C43_T50R have a specified reverse leakage current?
Yes, the BZX55C43_T50R specifies a maximum reverse leakage current (IR) of 0.1 μA at VR = 32 V and Ta = 25°C. This low leakage supports high-impedance applications like sensor biasing and precision op-amp references. The value is confirmed in the Electrical Characteristics table and remains ≤ 0.1 μA up to 125°C per note in the datasheet.
What package type is used for BZX55C43_T50R?
The BZX55C43_T50R uses the DO-35 glass axial package, identified by a cathode band marking and standardized 3/8" lead length. This hermetically sealed package supports operation from -65°C to +200°C and is mechanically compatible with legacy through-hole assembly processes. The DO-35 designation is explicitly stated in the datasheet's package diagram and top-marking section.
BZX55C43_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):
- 43 V
- Tolerance:
- ±7%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 90 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 32 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.3 V @ 100 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
BZX55C43_T50R FAQ
1.How can I place an order for BZX55C43_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX55C43_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 BZX55C43_T50R reliable?
The price and inventory of BZX55C43_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX55C43_T50R is usually 5 days.
3.What payment methods are accepted for BZX55C43_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX55C43_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX55C43_T50R?
BZX55C43_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX55C43_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 BZX55C43_T50R?
For technical support, including BZX55C43_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX55C43_T50R requirements.
6.How does Aetrix verify that BZX55C43_T50R is sourced from the original manufacturer or authorized distributors?
All BZX55C43_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 BZX55C43_T50R meets industry standards.
7.What is the process for return or replacement of BZX55C43_T50R?
All BZX55C43_T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX55C43_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 BZX55C43_T50R part is unused and in its original packaging.
Return procedure for BZX55C43_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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