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onsemi BZX85C24-T50R
- Part No.:
- BZX85C24-T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
BZX85C24-T50R.pdf
- Description:
- DIODE ZENER 24V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:42,000
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Product details
Overview
BZX85C24-T50R from Fairchild Semiconductor is a 24 V, ±5% tolerance, 1 W axial-leaded Zener diode in DO-41 glass package, rated for 25 Ω zener impedance at 5 mA test current and 0.5 μA maximum leakage at 19 V reverse voltage, used for precision voltage regulation and overvoltage protection in power supply feedback loops.
For engineers reviewing the BZX85C24-T50R datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, cathode identification, DO-41 mechanical dimensions, and direct alternatives with documented voltage/impedance trade-offs.
Technical Context
The BZX85C24-T50R operates as a two-terminal voltage reference device with sharp reverse-breakdown characteristics, designed for stable DC voltage clamping under variable load and temperature conditions. Its 24 V nominal zener voltage is specified at IZ = 5 mA, with 25 Ω dynamic impedance (ZZ) ensuring minimal output variation across operating current range.
Thermal performance is defined by 6.67 mW/°C derating above 50°C lead temperature, supporting reliable operation up to +200°C junction temperature. The DO-41 glass package provides hermetic sealing and standardized axial leads compatible with through-hole PCB assembly and manual soldering processes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 22.8 V min / 25.6 V max at IZ = 5 mA - defines regulated output range for feedback or clamp circuits |
| Power Dissipation (PD) | 1.0 W @ TL ≤ 50°C - sets maximum continuous power handling before thermal derating applies |
| Zener Impedance (ZZ) | 25 Ω @ IZ = 5 mA - determines output voltage stability under load transients |
| Leakage Current (IR) | 0.5 μA max @ VR = 19 V - ensures minimal standby current in high-impedance bias networks |
| Operating Temperature | –65°C to +200°C - supports industrial and automotive under-hood applications without derating |
| Forward Voltage (VF) | 1.2 V max @ IF = 200 mA - enables use as low-drop rectifier or ESD clamp in bidirectional paths |
Pinout & Package
DO-41 glass axial package with cathode indicated by a single color band; leads are unmarked anode/cathode terminals requiring orientation verification via multimeter diode test or schematic polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias | Connected to lower-potential node in clamp or regulator configuration |
| Cathode | Current exit terminal in reverse breakdown | Connected to regulated output or reference node; marked with color band |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables predictable regulation without post-production trimming in cost-sensitive designs |
| 1 W power rating with 6.67 mW/°C derating | Supports sustained dissipation in compact enclosures with controlled lead temperature |
| 25 Ω zener impedance at 5 mA | Minimizes output voltage deviation during 10–100 mA load steps in feedback networks |
| 0.5 μA max leakage at 19 V | Preserves accuracy in high-resistance voltage divider biasing of op-amps or comparators |
| DO-41 glass package | Provides moisture resistance and thermal stability superior to plastic-packaged Zeners |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters using optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Zener reference providing precise 24 V threshold to TL431 shunt regulator input. Use Value: Maintains ±1% output regulation across line/load variations due to tight 24 V tolerance and low ZZ. |
Use Scenario: Protecting microcontroller I/O pins against transient surges exceeding 20 V. IC Role / Device Role / Timing Role: Bidirectional clamp limiting voltage to 24 V in series with current-limiting resistor. Use Value: Absorbs 1 W surge energy without degradation, leveraging 200°C max junction temperature rating. |
| Industrial Sensor Signal Conditioning | Programmable Logic Controller Input Protection |
Use Scenario: Biasing analog front-end circuitry for 4–20 mA current-loop sensors operating in 24 V systems. IC Role / Device Role / Timing Role: Stable 24 V reference for DAC output scaling and ADC reference buffer. Use Value: Delivers <0.1% drift over –40°C to +85°C ambient due to low thermal coefficient and DO-41 thermal mass. |
Use Scenario: Safeguarding PLC digital input modules connected to 24 V field wiring subject to inductive kickback. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed across input terminals before series current limiter. Use Value: Withstands repeated 100 V/100 ns transients per IEC 61000-4-4, validated by 0.5 μA leakage at 19 V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A | 24 V, ±5%, 1 W, 25 Ω ZZ, DO-41 - identical electrical specs but different marking convention and RoHS status history | No functional difference in regulation or clamping; legacy part with broader distributor stock but no active Fairchild support | Select when sourcing legacy BOMs or where cross-manufacturer qualification is already complete |
| BZX85C24-TR | Same 24 V, ±5%, 1 W, 25 Ω ZZ, DO-41 - differs only in tape-and-reel packaging (TR vs T50R) and date-code format | Identical electrical and thermal behavior; T50R denotes 500-piece reel, TR denotes standard 2,000-piece reel | Choose BZX85C24-T50R for prototyping or low-volume production requiring smaller reels |
Compared with 1N4749A and BZX85C24-TR, the BZX85C24-T50R offers identical regulation performance and thermal capability, with selection driven solely by packaging preference (500-piece reel) and current Fairchild manufacturing traceability.
Availability
BZX85C24-T50R is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor interfaces, overvoltage protection circuits, and programmable logic controller input stages requiring stable component supply with full RoHS compliance and DO-41 mechanical consistency.
Supply support for BZX85C24-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; its legacy Zener diode portfolio remains widely deployed in industrial and automotive systems.
The BZX85C series was engineered for high-reliability voltage reference and clamping in harsh environments, emphasizing thermal robustness, tight tolerance control, and glass-package hermeticity for long-term stability.
FAQ
What is the zener voltage tolerance of BZX85C24-T50R?
The BZX85C24-T50R has a ±5% zener voltage tolerance, meaning its nominal 24 V breakdown occurs between 22.8 V and 25.6 V at 5 mA test current. This tolerance is guaranteed across the full operating temperature range and is measured under standardized lead-temperature conditions per Fairchild's Rev. F1 datasheet.
Does BZX85C24-T50R support high-temperature operation?
Yes, the BZX85C24-T50R is rated for junction temperatures from –65°C to +200°C and features 6.67 mW/°C thermal derating above 50°C lead temperature. Its DO-41 glass package contributes to thermal stability, making it suitable for under-hood automotive or industrial control cabinet applications where ambient exceeds 85°C.
How is cathode identification implemented on BZX85C24-T50R?
The cathode of the BZX85C24-T50R is identified by a single color band on the DO-41 glass body, consistent with industry-standard axial diode marking. This band must be oriented toward the higher-potential node in reverse-bias regulation or clamping configurations, and polarity should be confirmed with a multimeter diode test prior to PCB assembly.
What is the maximum leakage current specification for BZX85C24-T50R?
The BZX85C24-T50R specifies a maximum leakage current of 0.5 μA at VR = 19 V, measured at 25°C. This low leakage ensures minimal error in high-impedance voltage divider networks and preserves accuracy in precision reference applications such as sensor excitation or comparator threshold setting.
Is BZX85C24-T50R RoHS compliant?
Yes, the BZX85C24-T50R is RoHS compliant per Fairchild's product status documentation, with full compliance verified under IPC-1752 and supported by RoHS/REACH/JIG certificates of compliance. This applies to both the DO-41 package construction and internal die materials.
BZX85C24-T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 24 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 25 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 17 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AL (DO-41)
BZX85C24-T50R FAQ
1.How can I place an order for BZX85C24-T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX85C24-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 BZX85C24-T50R reliable?
The price and inventory of BZX85C24-T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C24-T50R is usually 5 days.
3.What payment methods are accepted for BZX85C24-T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C24-T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX85C24-T50R?
BZX85C24-T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX85C24-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 BZX85C24-T50R?
For technical support, including BZX85C24-T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C24-T50R requirements.
6.How does Aetrix verify that BZX85C24-T50R is sourced from the original manufacturer or authorized distributors?
All BZX85C24-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 BZX85C24-T50R meets industry standards.
7.What is the process for return or replacement of BZX85C24-T50R?
All BZX85C24-T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C24-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 BZX85C24-T50R part is unused and in its original packaging.
Return procedure for BZX85C24-T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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