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onsemi 1N977B_T50R
- Part No.:
- 1N977B_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N977B_T50R.pdf
- Description:
- DIODE ZENER 47V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:5,340
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Product details
Overview
1N977B_T50R from Fairchild Semiconductor is a 44.65 V, ±5% tolerance, 500 mW glass-passivated Zener diode in DO-35 package, 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 1N977B_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, dynamic impedance at rated current, maximum reverse leakage at specified test voltage, thermal derating behavior above 75°C, and DO-35 mechanical compatibility with through-hole PCB layouts.
Technical Context
The 1N977B_T50R operates as a two-terminal voltage reference device with sharp reverse breakdown characteristics. Its zener voltage is specified at IZ = 5 mA, with typical dynamic impedance of 6.4 Ω and maximum reverse leakage of 0.25 μA at 35.8 V.
It follows JEDEC-standard DO-35 glass axial package construction with cathode band marking, supports operation from –65°C to +200°C, and exhibits linear thermal derating of 4.0 mW/°C above 75°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 44.65 V nominal, ±5% tolerance - defines stable regulation point under 5 mA test current |
| Power Dissipation (PD) | 500 mW at TL ≤ 75°C - sets maximum continuous DC power handling before thermal derating |
| Zener Impedance (ZZ) | 6.4 Ω at IZ = 5 mA - determines output voltage stability under load variation |
| Reverse Leakage (IR) | 0.25 μA max at VR = 35.8 V - ensures minimal quiescent current in high-impedance bias networks |
| Operating Temperature | –65°C to +200°C - enables use in automotive under-hood, industrial control, and aerospace environments |
| Thermal Derating | 4.0 mW/°C above 75°C - requires thermal design margin for sustained operation above ambient threshold |
Pinout & Package
DO-35 glass axial package with cathode identified by color band; two-terminal device with no internal polarity-sensitive circuitry beyond standard anode/cathode junction orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage side | Connected to ground or lower potential node in reverse-biased regulation configuration |
| Cathode | Zener breakdown terminal / high-voltage side | Connected to input rail or regulated node; marked by colored band per JEDEC standard |
Key Features
| Feature | Design Value |
|---|---|
| ±5% VZ tolerance | Enables predictable regulation without post-assembly trimming in mid-precision applications |
| Low ZZ (6.4 Ω) | Maintains <±0.1 V output deviation across ±1 mA load current changes at nominal VZ |
| Ultra-low IR (0.25 μA) | Minimizes error in high-resistance voltage divider networks used for feedback scaling |
| DO-35 glass passivation | Provides hermetic sealing and long-term parameter stability vs. plastic-packaged alternatives |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Used in TL431-based or discrete op-amp feedback networks to set output voltage in AC/DC adapters and DC/DC converters. IC Role / Device Role / Timing Role: Precision voltage reference element defining regulation threshold via resistive divider. Use Value: Tight 44.65 V ±5% tolerance ensures consistent output voltage across production batches without calibration. | Use Scenario: Placed across sensitive IC inputs or bus lines to clamp transient overvoltages exceeding safe operating limits. IC Role / Device Role / Timing Role: Fast-acting shunt protection device that conducts only when line voltage exceeds 44.65 V. Use Value: Low 6.4 Ω dynamic impedance ensures rapid clamping response and minimal overshoot during ESD or surge events. |
| Industrial Sensor Signal Conditioning | Programmable Reference Voltage Source |
Use Scenario: Provides stable bias voltage for bridge sensor excitation or ADC reference scaling in temperature/pressure transducers. IC Role / Device Role / Timing Role: Low-drift, low-noise DC reference source in analog front-end circuits. Use Value: Ultra-low 0.25 μA leakage prevents loading errors in high-impedance sensor interfaces. | Use Scenario: Configured with external resistors to generate custom reference voltages in programmable power supplies or test equipment. IC Role / Device Role / Timing Role: Fixed-voltage building block enabling scalable reference generation via resistor ratio networks. Use Value: DO-35 mechanical compatibility allows direct replacement in legacy designs using 1N9xx series references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4755A | Same nominal VZ (44 V), but ±5% tolerance and higher ZZ (15 Ω) | Higher dynamic impedance reduces regulation accuracy under varying load | Acceptable where tighter regulation is not required and cost is prioritized |
| BZX55-C43 | VZ = 43 V (±5%), DO-35, ZZ = 70 Ω at 5 mA | Lower voltage rating and significantly higher impedance limit use in precision feedback | Suitable for non-critical clamping where 43 V threshold suffices and sourcing constraints exist |
Compared with 1N977B_T50R, the 1N4755A offers identical tolerance but poorer regulation stability due to 135% higher dynamic impedance, while BZX55-C43 trades 1.65 V lower VZ for substantially degraded voltage control fidelity-making 1N977B_T50R optimal for applications demanding both accuracy and low-impedance behavior.
Availability
1N977B_T50R is available at Aetrix Electronics and suitable for switch-mode power supply feedback, overvoltage clamp protection, and industrial sensor signal conditioning requiring stable component supply and long-term parametric consistency.
Supply support for 1N977B_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 1N957B–1N979B series was developed as a JEDEC-standardized family of general-purpose, glass-passivated Zener diodes targeting industrial and commercial power regulation and protection functions.
FAQ
What is the nominal zener voltage and tolerance of the 1N977B_T50R?
The 1N977B_T50R has a nominal zener voltage of 44.65 V with a tolerance of ±5%, measured at a test current of 5 mA and lead temperature of 30°C. This specification ensures predictable regulation performance across manufacturing lots and supports use in applications where moderate voltage accuracy is required without post-production trimming.
What is the maximum power dissipation and thermal derating behavior of the 1N977B_T50R?
The 1N977B_T50R is rated for 500 mW power dissipation at lead temperature ≤75°C, with linear derating of 4.0 mW/°C above that temperature. This means usable power drops to 400 mW at 100°C lead temperature, requiring thermal layout consideration in enclosed or high-ambient environments where sustained power operation is needed.
What is the zener impedance and reverse leakage specification for the 1N977B_T50R?
The 1N977B_T50R exhibits a typical zener impedance (ZZ) of 6.4 Ω at 5 mA test current and a maximum reverse leakage current (IR) of 0.25 μA at 35.8 V. These values directly impact regulation stability and bias network loading-low ZZ maintains tight voltage control under load shifts, while ultra-low IR avoids errors in high-resistance divider configurations.
Which package type does the 1N977B_T50R use, and how is polarity marked?
The 1N977B_T50R uses the JEDEC-standard DO-35 glass axial package, with cathode polarity indicated by a visible color band on the body. This marking aligns with industry conventions and ensures correct orientation during manual or automated assembly, critical for proper reverse-bias operation in regulation and clamping circuits.
What is the operating and storage temperature range for the 1N977B_T50R?
The 1N977B_T50R is specified for operation and storage across –65°C to +200°C, making it suitable for extreme-environment applications such as automotive under-hood electronics, downhole instrumentation, and industrial motor controls. This wide range reflects the robustness of its glass-passivated junction and DO-35 hermetic construction.
1N977B_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):
- 47 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 105 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 35.8 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N977B_T50R FAQ
1.How can I place an order for 1N977B_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N977B_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 1N977B_T50R reliable?
The price and inventory of 1N977B_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N977B_T50R is usually 5 days.
3.What payment methods are accepted for 1N977B_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N977B_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N977B_T50R?
1N977B_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N977B_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 1N977B_T50R?
For technical support, including 1N977B_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N977B_T50R requirements.
6.How does Aetrix verify that 1N977B_T50R is sourced from the original manufacturer or authorized distributors?
All 1N977B_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 1N977B_T50R meets industry standards.
7.What is the process for return or replacement of 1N977B_T50R?
All 1N977B_T50R units undergo pre-shipment inspection (PSI). If there is an issue with 1N977B_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 1N977B_T50R part is unused and in its original packaging.
Return procedure for 1N977B_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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