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onsemi 1N4746A-T50A
- Part No.:
- 1N4746A-T50A
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4746A-T50A.pdf
- Description:
- DIODE ZENER 18V 1W DO41
- Quantity:
- Payment:
- Shipping:
Inventory:8,205
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Product details
Overview
1N4746A-T50A from ON Semiconductor is a 18 V, 1 W, 5% tolerance Zener diode in DO-41 glass package, designed for voltage regulation and reference applications at 20 mA test current, with 14 Ω dynamic impedance and 0.25 μA leakage at 14.4 V reverse bias.
For engineers reviewing the 1N4746A-T50A datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy (17.1–18.9 V), thermal derating (6.67 mW/°C above 50°C), junction temperature range (–65 to +200°C), and non-repetitive peak reverse surge capability (250 mA).
Technical Context
The 1N4746A-T50A operates as a silicon planar Zener diode with controlled avalanche breakdown, optimized for stable DC voltage reference in power supply feedback loops and overvoltage protection circuits. Its 18 V nominal Zener voltage is specified at 20 mA test current (IZ), with tight 5% tolerance and low dynamic impedance (14 Ω @ IZ) ensuring minimal output variation under load changes.
Thermal performance is defined by 1.0 W power dissipation at lead temperature ≤50°C (3/8″ lead length), derating linearly at 6.67 mW/°C above that point. The device supports operation across –65°C to +200°C, enabling use in industrial and automotive environments where wide ambient temperature swings occur.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1–18.9 V min–max at 20 mA; ensures precise regulation within ±5% for feedback and reference designs |
| Power Dissipation (PD) | 1.0 W @ TL ≤50°C; defines maximum continuous steady-state power handling before thermal shutdown risk |
| Zener Impedance (ZZ) | 14 Ω @ IZ = 20 mA; indicates low AC impedance for stable regulation under varying load currents |
| Leakage Current (IR) | 0.25 μA @ VR = 14.4 V; confirms minimal standby current in high-impedance bias networks |
| Operating Temperature | –65°C to +200°C; supports deployment in under-hood automotive, industrial control, and downhole electronics |
| Non-Repetitive Peak Reverse Current | 250 mA @ 8.3 ms; enables transient overvoltage clamping without device failure |
Pinout & Package
DO-41 glass axial package with cathode band marking; two-terminal device (anode and cathode) requiring no PCB footprint adaptation beyond standard DO-41 land pattern.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground node | Connected to circuit ground or lower-potential rail when used in shunt regulation configuration |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input voltage source; maintains stable 18 V relative to anode during reverse bias operation |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Enables predictable regulation without post-production trimming in cost-sensitive power supplies |
| Low dynamic impedance (14 Ω) | Minimizes output voltage deviation under ±10 mA load transients in feedback divider networks |
| High surge current rating (250 mA) | Provides robustness against ESD and line transients without external TVS supplementation |
| Wide operating temperature range | Eliminates need for thermal derating calculations in unheated enclosures or engine bay locations |
Applications
| Switching Power Supply Feedback | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters via optocoupler-coupled feedback loop. IC Role / Device Role: Precision voltage reference establishing error amplifier threshold. Use Value: 18 V Zener voltage sets stable 12 V output using resistor divider; 14 Ω impedance prevents loop instability under load steps. |
Use Scenario: Clamping 24 V rail against surges exceeding 20 V in industrial PLC I/O modules. IC Role / Device Role: Shunt overvoltage limiter protecting downstream ADC inputs and microcontroller pins. Use Value: 250 mA non-repetitive surge rating absorbs 100 V/1 A transients per IEC 61000-4-5 Level 3 without degradation. |
| Reference Voltage Source | DC-DC Converter Bias Network |
Use Scenario: Generating stable 18 V reference for analog sensor signal conditioning in automotive cabin sensors. IC Role / Device Role: Primary voltage reference for op-amp gain-setting and offset calibration. Use Value: –65°C to +200°C operating range ensures functionality across cold-start to hot-soak conditions without drift compensation. |
Use Scenario: Providing gate drive bias for high-side N-channel MOSFETs in synchronous buck controllers. IC Role / Device Role: Zener-clamped bootstrap voltage source maintaining gate-to-source margin. Use Value: 0.25 μA leakage at 14.4 V minimizes quiescent current draw in always-on bias networks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A-TP (Micro Commercial Co.) | Same 18 V nominal Zener voltage, 5% tolerance, DO-41 package; 15 Ω ZZ vs. 14 Ω; 0.5 μA IR @ 14.4 V | Slightly higher leakage limits use in ultra-low-power battery monitoring; otherwise functionally interchangeable | Select when sourcing flexibility required and minor ZZ/IR variation is acceptable |
| BZX55C18 (Vishay) | 18 V, 5% tolerance, DO-35 package; 20 Ω ZZ; 0.1 μA IR @ 14.4 V; 500 mW PD | Lower power rating restricts use to <500 mW applications; smaller DO-35 footprint requires layout change | Choose for space-constrained boards where 500 mW suffices and thermal mass is limited |
Compared with 1N4746A-T50A, the 1N4746A-TP offers near-identical electrical behavior with minor leakage trade-off, while BZX55C18 reduces power handling and changes package-requiring PCB revision but enabling tighter board area utilization.
Availability
1N4746A-T50A is available at Aetrix Electronics and suitable for switching power supply feedback, overvoltage protection, and precision reference voltage applications requiring stable component supply, long-term lifecycle support, and traceable manufacturing origin.
Supply support for 1N4746A-T50A 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, and consumer markets.
The 1N47xxA series is part of ON Semiconductor's legacy Zener diode portfolio, engineered for high-reliability voltage regulation in cost-sensitive, high-volume power conversion and protection circuits.
FAQ
What is the Zener voltage tolerance of the 1N4746A-T50A?
The 1N4746A-T50A has a ±5% Zener voltage tolerance, meaning its nominal 18 V rating spans 17.1 V to 18.9 V at 20 mA test current. This tolerance is guaranteed across the full operating temperature range and reflects factory binning-no additional calibration is needed in production. The 1N4746A-T50A meets this spec per ON Semiconductor's 1N4728A–1N4758A datasheet Rev. 8.
Can the 1N4746A-T50A be used in surface-mount designs?
No-the 1N4746A-T50A uses a DO-41 axial glass package with leads intended for through-hole mounting. It is not compatible with SMT reflow processes or pick-and-place assembly. For surface-mount equivalents, consider the MMBZ5245B (18 V, SOT-23) or NZ9F18ST5G (18 V, SOD-923), both requiring redesign of the PCB footprint and thermal relief.
What is the maximum allowable junction temperature for the 1N4746A-T50A?
The 1N4746A-T50A has a maximum junction temperature (TJ) of +200°C, matching its storage temperature limit. This rating assumes proper lead length (3/8″) and ambient thermal management. At 20 mA and 18 V, power dissipation is 360 mW-well below the 1.0 W rating at TL ≤50°C, allowing safe operation up to ~150°C board temperature with adequate copper pour.
How does the 1N4746A-T50A perform under transient surge conditions?
The 1N4746A-T50A supports non-repetitive peak reverse current (IZSM) of 250 mA for 8.3 ms, per IEC 61000-4-5 surge testing methodology. This allows it to clamp short-duration transients without degradation, provided average power remains within 1.0 W and thermal recovery time is observed between events. The 1N4746A-T50A is not rated for repetitive surges.
Is the 1N4746A-T50A RoHS compliant and halogen-free?
Yes-the 1N4746A-T50A is RoHS compliant and halogen-free per ON Semiconductor's product compliance documentation. It meets EU Directive 2011/65/EU and JEDEC JS709B requirements. The "T50A" suffix denotes tape-and-reel packaging with RoHS-compliant plating and Pb-free solder compatibility, confirmed in ON Semiconductor's environmental compliance reports.
1N4746A-T50A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- 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-T50A FAQ
1.How can I place an order for 1N4746A-T50A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746A-T50A 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-T50A reliable?
The price and inventory of 1N4746A-T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746A-T50A is usually 5 days.
3.What payment methods are accepted for 1N4746A-T50A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746A-T50A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746A-T50A?
1N4746A-T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746A-T50A 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-T50A?
For technical support, including 1N4746A-T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746A-T50A requirements.
6.How does Aetrix verify that 1N4746A-T50A is sourced from the original manufacturer or authorized distributors?
All 1N4746A-T50A 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-T50A meets industry standards.
7.What is the process for return or replacement of 1N4746A-T50A?
All 1N4746A-T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746A-T50A, 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-T50A part is unused and in its original packaging.
Return procedure for 1N4746A-T50A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746A-T50A Tags
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BZT52C5V6T-7
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MMSZ5231B-7-F
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BZX84C3V3LT1G
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MMSZ5245BS-7-F
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MMSZ4682T1G
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BZT52C15S-7-F
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MM5Z5V1ST1G
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SMAJ4744A-TP
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