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onsemi 1N5256BTR
- Part No.:
- 1N5256BTR
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5256BTR.pdf
- Description:
- DIODE ZENER 30V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:330,000
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Product details
Overview
1N5256BTR from Fairchild Semiconductor is a 30 V, 5% tolerance Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 25°C, with 49 Ω dynamic impedance at 20 mA test current and ±0.09 %/°C temperature coefficient - used for precision voltage reference and overvoltage protection in low-power analog circuits.
For engineers reviewing the 1N5256BTR datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, cathode identification, and direct replacement options for stable voltage regulation in space-constrained PCB designs.
Technical Context
The 1N5256BTR operates as a two-terminal silicon Zener diode optimized for reverse-biased breakdown regulation. Its 30 V nominal Zener voltage is specified at 20 mA test current (IZ), with a maximum dynamic impedance (ZZ) of 49 Ω under those conditions and a tightly controlled ±0.09 %/°C temperature coefficient ensuring stable reference performance across industrial temperature ranges.
It features a hermetically sealed DO-35 glass package with axial leads, cathode identified by a color band, and absolute maximum ratings including 500 mW power dissipation at 25°C, derating linearly at 4.0 mW/°C above 50°C, and junction/storage temperature range from –65°C to +200°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 30 V nominal, min 28.5 V / max 31.5 V at IZ = 20 mA - defines regulated output voltage tolerance window |
| Power Dissipation (PD) | 500 mW at TA = 25°C - sets maximum continuous power handling before thermal shutdown risk |
| Dynamic Impedance (ZZ) | 49 Ω max at IZ = 20 mA - determines output voltage stability under load current variation |
| Temperature Coefficient (TC) | ±0.09 %/°C - quantifies VZ drift per degree Celsius, critical for temperature-sensitive references |
| Reverse Leakage (IR) | 0.1 μA max at VR = 23 V - ensures minimal quiescent current in standby regulation circuits |
| Forward Voltage (VF) | 1.2 V max at IF = 200 mA - defines conduction threshold when used in bidirectional clamp configurations |
Pinout & Package
DO-35 glass axial-leaded package with cathode indicated by a single color band on the body; total length 4.56 mm, diameter 1.91 mm, weight 0.137 g; JEDEC DO-204AH compliant, hermetically sealed.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Positive terminal in forward bias; connected to lower-potential node in Zener regulation | Accepts forward current up to 200 mA; must be tied to ground or common reference in shunt regulator topology |
| Cathode | Negative terminal in forward bias; higher-potential node in Zener operation | Connected to input voltage source via series resistor; provides stable 30 V reference to load when reverse-biased |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Ensures predictable regulation within ±1.5 V of 30 V, enabling reliable design margining without trimming |
| Hermetic DO-35 glass package | Provides long-term reliability and moisture resistance in humid or high-reliability environments |
| Low leakage current | 0.1 μA max at 23 V reverse voltage minimizes power loss in battery-powered sensor references |
| Controlled temperature coefficient | ±0.09 %/°C allows use in ambient temperature ranges up to +85°C without significant VZ drift |
Applications
| Industrial Sensor Signal Conditioning | Low-Power Microcontroller Voltage Reference |
|---|---|
Use Scenario: Stabilizing excitation voltage for resistive bridge sensors in PLC analog input modules. IC Role / Device Role / Timing Role: Shunt Zener regulator providing fixed 30 V reference to op-amp excitation circuitry. Use Value: Maintains <±0.5% reference accuracy over –40°C to +85°C due to low TC and tight VZ tolerance. | Use Scenario: Generating precise 3.3 V or 5 V supply rail from higher battery voltage in portable IoT nodes. IC Role / Device Role / Timing Role: Passive voltage reference in resistor-Zener divider feeding LDO feedback network. Use Value: Enables stable microcontroller reset threshold and ADC reference with sub-μA quiescent draw. |
| DC-DC Converter Feedback Network | Overvoltage Protection Clamp |
Use Scenario: Setting output voltage in isolated flyback converters using optocoupler feedback loop. IC Role / Device Role / Timing Role: Precision Zener element in secondary-side TL431-like reference path. Use Value: Delivers 30 V reference with <50 Ω impedance, minimizing feedback error contribution. | Use Scenario: Protecting 24 V industrial I/O lines against transient surges exceeding 35 V. IC Role / Device Role / Timing Role: Fast-acting shunt clamp triggered at 30 V Zener breakdown. Use Value: Limits voltage excursion to ≤31.5 V (max VZ) while dissipating <500 mW during 8.3 ms transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A | 30 V nominal, 5% tolerance, 1 W power rating, DO-41 package - higher PD but larger footprint | Suitable for higher-power regulation where board space permits larger axial package | Select when >500 mW continuous dissipation is required and DO-41 layout is acceptable |
| BZX55C30 | 30 V nominal, 5% tolerance, 500 mW, DO-35 package - same form factor, ±5% tolerance, but ±0.1 %/°C TC | Compatible drop-in replacement with identical mechanical fit and near-identical electrical behavior | Choose for second-source availability with no PCB changes; verify TC impact in wide-temp designs |
Compared with 1N5256BTR, the 1N4749A offers double the power rating but requires more board area, while the BZX55C30 matches the DO-35 footprint and VZ spec but has slightly higher temperature sensitivity - both serve distinct trade-offs between thermal headroom and spatial constraint.
Availability
1N5256BTR is available at Aetrix Electronics and suitable for industrial sensor conditioning, low-power microcontroller reference, DC-DC converter feedback, and overvoltage protection requiring stable component supply and consistent parametric performance.
Supply support for 1N5256BTR 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, signal conditioning, and discrete components before its acquisition by ON Semiconductor in 2016.
The 1N52xxB series was designed for general-purpose, low-power Zener regulation in cost-sensitive consumer, industrial, and computing applications - emphasizing tight voltage tolerance, stable TC, and robust DO-35 packaging.
FAQ
What is the Zener voltage tolerance of the 1N5256BTR?
The 1N5256BTR has a nominal Zener voltage of 30 V with a guaranteed tolerance of ±5%, meaning the actual measured VZ falls between 28.5 V and 31.5 V when tested at 20 mA. This tolerance is confirmed in the Fairchild 1N5221B–1N5263B datasheet Rev. 4.10, Table "Electrical Characteristics" for device 1N5256B. The 1N5256BTR maintains this specification across its qualified operating temperature range.
Does the 1N5256BTR have a specified forward voltage?
Yes, the 1N5256BTR has a maximum forward voltage (VF) of 1.2 V at a forward current (IF) of 200 mA, as stated in the "Electrical Characteristics" table of the Fairchild datasheet. This parameter is relevant when the device is used in bidirectional clamping or reverse-polarity protection circuits. The 1N5256BTR's VF remains consistent with other devices in the 1N52xxB family and supports design of low-loss rectifier or clamp stages.
What is the thermal derating behavior of the 1N5256BTR above 50°C?
The 1N5256BTR derates linearly at 4.0 mW/°C above an ambient temperature of 50°C, reducing its maximum allowable power dissipation from 500 mW at 25°C to zero at approximately 175°C. This derating slope is defined in the "Absolute Maximum Ratings" table and applies to continuous operation. Engineers must apply this derating when designing 1N5256BTR-based regulators for high-temperature enclosures or unventilated environments.
Is the 1N5256BTR compatible with lead-free soldering processes?
Yes, the 1N5256BTR's DO-35 glass package supports lead-free reflow soldering with a maximum lead temperature of +230°C for 10 seconds at 1/16 inch from the case, as specified in the Absolute Maximum Ratings. This makes the 1N5256BTR suitable for modern RoHS-compliant assembly lines. The 1N5256BTR's glass body and axial leads withstand standard J-STD-020 profiles without cracking or delamination.
How is the cathode identified on the 1N5256BTR package?
The cathode of the 1N5256BTR is marked by a single color band on the glass body of the DO-35 package, consistent with industry-standard polarity marking for axial-leaded diodes. This band aligns with the cathode terminal - the end that connects to the higher-potential node during Zener operation. The 1N5256BTR's marking follows JEDEC DO-204AH and Fairchild's top-marking specification, ensuring unambiguous orientation during manual or automated placement.
1N5256BTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 30 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 49 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 23 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N5256BTR FAQ
1.How can I place an order for 1N5256BTR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5256BTR 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 1N5256BTR reliable?
The price and inventory of 1N5256BTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5256BTR is usually 5 days.
3.What payment methods are accepted for 1N5256BTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5256BTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5256BTR?
1N5256BTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5256BTR 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 1N5256BTR?
For technical support, including 1N5256BTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5256BTR requirements.
6.How does Aetrix verify that 1N5256BTR is sourced from the original manufacturer or authorized distributors?
All 1N5256BTR 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 1N5256BTR meets industry standards.
7.What is the process for return or replacement of 1N5256BTR?
All 1N5256BTR units undergo pre-shipment inspection (PSI). If there is an issue with 1N5256BTR, 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 1N5256BTR part is unused and in its original packaging.
Return procedure for 1N5256BTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5256BTR Tags
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