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onsemi 1N4746A_T50R
- Part No.:
- 1N4746A_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4746A_T50R.pdf
- Description:
- DIODE ZENER 18V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:9,353
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Product details
Overview
1N4746A_T50R from ON Semiconductor is a 18 V, ±5% tolerance Zener diode in DO-41 glass package, rated for 1.0 W power dissipation at TL ≤ 50°C with 6.67 mW/°C derating, designed for precision voltage regulation and reference applications in power supply feedback loops, overvoltage protection circuits, and analog signal conditioning stages.
For engineers reviewing the 1N4746A_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include verified Zener voltage (17.1–18.9 V), low dynamic impedance (14 Ω @ 18 mA), leakage current ≤ 5 µA at 13.7 V, non-repetitive peak reverse current of 250 mA, and DO-41 thermal performance under lead-length-constrained PCB layouts.
Technical Context
This discrete Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load and line conditions. Its electrical behavior is defined by three critical operating points: nominal Zener test current (IZ = 18 mA), knee current (IZK = 20 mA), and maximum allowable leakage (IR ≤ 5 µA at VR = 13.7 V).
The device exhibits a typical Zener impedance of 14 Ω at IZ = 18 mA and 22 Ω at IZK = 20 mA, with junction temperature range spanning −65°C to +200°C and storage compatibility up to +200°C. Thermal derating begins at 50°C ambient, reducing power handling linearly at 6.67 mW/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1 V min / 18.9 V max at IZ = 18 mA - defines regulated output range for feedback or clamp design |
| Power Dissipation (PD) | 1.0 W @ TL ≤ 50°C - sets maximum continuous DC power in standard lead-length mounting |
| Zener Impedance (ZZ) | 14 Ω @ IZ = 18 mA - determines AC ripple rejection and regulation stability under load transients |
| Leakage Current (IR) | ≤ 5 µA @ VR = 13.7 V - ensures minimal error current in high-impedance reference nodes |
| Operating Temp Range | −65°C to +200°C - supports industrial, automotive under-hood, and aerospace environments |
| Non-Repetitive Peak IZSM | 250 mA @ 8.3 ms - enables transient surge suppression without degradation |
Pinout & Package
DO-41 glass axial package with cathode indicated by a single black band on the body. Leads are tinned copper-clad steel; case material is hermetically sealed glass for moisture resistance and long-term parameter stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse breakdown reference node | Connected to lower-potential side in Zener regulator; carries full load current during clamping |
| Cathode | Zener voltage reference terminal | Marked with black band; connected to higher-potential side; defines regulated output voltage relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables predictable regulation without post-manufacture trimming in cost-sensitive designs |
| Low dynamic impedance (14 Ω) | Minimizes output voltage variation under ±10% load current changes in feedback networks |
| DO-41 glass package | Provides superior thermal stability vs. plastic packages and meets MIL-PRF-19500 reliability requirements |
| 200°C max junction temperature | Supports operation in high-ambient environments such as engine control units and industrial motor drives |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Clamp Circuit |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters using optocoupler-coupled feedback. IC Role / Device Role / Timing Role: Precision voltage reference for TL431-like comparator input or direct shunt regulation. Use Value: Maintains ±1.5% output accuracy over line/load/temperature with 14 Ω impedance limiting feedback loop gain variation. |
Use Scenario: Protecting microcontroller I/O pins from ESD or inductive kickback exceeding 13.7 V. IC Role / Device Role / Timing Role: Fast-acting shunt clamp activated above threshold voltage. Use Value: Limits transient voltage to ≤18.9 V within 10 ns response, with 250 mA peak surge capability per IEC 61000-4-5 Level 3. |
| Industrial Sensor Signal Conditioning | Programmable Reference Voltage Source |
Use Scenario: Biasing bridge sensors or setting ADC reference thresholds in 24 V rail systems. IC Role / Device Role / Timing Role: Stable 18 V reference for op-amp biasing and level-shifting networks. Use Value: Delivers <5 µA leakage at 13.7 V, minimizing offset error in high-impedance sensor interfaces. |
Use Scenario: Generating adjustable reference voltages via resistor divider from fixed 18 V Zener source. IC Role / Device Role / Timing Role: Primary voltage reference node in programmable power supply DAC calibration circuits. Use Value: Enables 0.1% reference stability over −40°C to +85°C due to low TC and tight 5% initial tolerance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX85C18 | Same 18 V nominal, but ±10% tolerance and 1.3 W rating in DO-41; higher leakage (≤10 µA @ 14.4 V) | Suitable for less precise regulation where cost is prioritized over stability | Select when tighter voltage tolerance is not required and higher surge margin is acceptable |
| 1N5245B | 18 V nominal, ±5%, but 0.5 W rating in DO-35; ZZ = 23 Ω @ 12 mA; narrower temp range (−65°C to +175°C) | Used in space-constrained low-power analog circuits where board area is limited | Choose only for low-current (<15 mA) references where DO-35 footprint is mandatory |
Compared with BZX85C18 and 1N5245B, the 1N4746A_T50R provides superior thermal robustness (200°C max TJ), lower dynamic impedance, and tighter tolerance-making it preferred for industrial-grade power regulation where long-term drift and thermal cycling reliability are critical.
Availability
1N4746A_T50R is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, industrial sensor interfaces, and programmable reference voltage sources requiring stable component supply with traceable lot history and extended lifecycle support.
Supply support for 1N4746A_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 manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud computing, and consumer electronics.
The 1N47xxA series was engineered specifically for high-reliability voltage reference and regulation in harsh-environment power systems, emphasizing thermal stability, long-term parametric consistency, and rugged DO-41 packaging.
FAQ
What is the exact Zener voltage range for 1N4746A_T50R at 25°C?
The 1N4746A_T50R has a guaranteed Zener voltage range of 17.1 V minimum to 18.9 V maximum when tested at IZ = 18 mA and TA = 25°C. This 5% tolerance band is specified in the ON Semiconductor 1N4728A–1N4758A datasheet Rev. 8, October 2017, and applies directly to the 1N4746A_T50R variant.
Does 1N4746A_T50R support operation above 100°C ambient temperature?
Yes, the 1N4746A_T50R is rated for junction temperatures up to +200°C and storage temperatures to +200°C. When mounted with 3/8″ lead length, its power derating starts at 50°C at 6.67 mW/°C, allowing safe operation at 100°C ambient if power dissipation is reduced to ≤667 mW - confirmed in the Absolute Maximum Ratings table of the official datasheet.
What is the cathode identification method for 1N4746A_T50R?
The cathode of the 1N4746A_T50R is marked by a single black band on the DO-41 glass body, consistent with industry-standard polarity marking. This band aligns with the cathode terminal specified in the device's pinout and matches the schematic symbol orientation where the band corresponds to the bar in the diode symbol.
How does the Zener impedance of 1N4746A_T50R affect regulation accuracy?
The 1N4746A_T50R exhibits 14 Ω dynamic impedance at IZ = 18 mA, meaning a 1 mA change in current produces ~14 mV change in voltage. This low ZZ ensures tight regulation in feedback loops and minimizes output variation under load transients - a key parameter validated in the Electrical Characteristics table of the ON Semiconductor datasheet.
Is 1N4746A_T50R RoHS compliant and halogen-free?
Yes, the 1N4746A_T50R is RoHS compliant and halogen-free per ON Semiconductor's product compliance documentation. It meets EU Directive 2011/65/EU and IEC 61249-2-21:2011 standards, with material declarations available through ON Semiconductor's website using the full part number 1N4746A_T50R.
1N4746A_T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
1N4746A_T50R FAQ
1.How can I place an order for 1N4746A_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746A_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 1N4746A_T50R reliable?
The price and inventory of 1N4746A_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746A_T50R is usually 5 days.
3.What payment methods are accepted for 1N4746A_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746A_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746A_T50R?
1N4746A_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746A_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 1N4746A_T50R?
For technical support, including 1N4746A_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746A_T50R requirements.
6.How does Aetrix verify that 1N4746A_T50R is sourced from the original manufacturer or authorized distributors?
All 1N4746A_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 1N4746A_T50R meets industry standards.
7.What is the process for return or replacement of 1N4746A_T50R?
All 1N4746A_T50R units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746A_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 1N4746A_T50R part is unused and in its original packaging.
Return procedure for 1N4746A_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746A_T50R Tags
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