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onsemi 1N977B_T50A
- Part No.:
- 1N977B_T50A
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N977B_T50A.pdf
- Description:
- DIODE ZENER 47V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:3,957
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Product details
Overview
1N977B_T50A from Fairchild Semiconductor is a 44.65 V, ±5% tolerance, 500 mW glass-encapsulated 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_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy (44.65 V min/49.35 V max), dynamic impedance (6.4 Ω at 105 mA), leakage current (≤0.25 μA at 35.8 V), and thermal derating (4.0 mW/°C above 75°C).
Technical Context
The 1N977B_T50A operates as a two-terminal silicon Zener diode with controlled reverse-breakdown behavior, optimized for stable DC voltage reference generation under regulated current conditions. Its DO-35 glass package ensures hermetic sealing and low parasitic capacitance, supporting reliable operation across -65°C to +200°C ambient and junction temperatures.
It exhibits a nominal zener voltage of 44.65 V measured at 105 mA with 5% tolerance, dynamic impedance of 6.4 Ω at rated test current, and maximum zener current of 105 mA-dictated by its 500 mW power dissipation limit and thermal derating profile.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 44.65 V min / 49.35 V max at IZ = 105 mA - defines usable regulation range for feedback or clamp circuits |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous power handling before thermal derating applies |
| Zener Impedance (ZZ) | 6.4 Ω @ IZ = 105 mA - determines output voltage stability under load transients |
| Reverse Leakage (IR) | ≤0.25 μA @ VR = 35.8 V - ensures minimal error current in high-impedance reference nodes |
| Max Zener Current (IZM) | 105 mA - derived from PD and VZ, limits safe operating current in shunt regulator designs |
| Operating Temp Range | -65°C to +200°C - enables use in automotive under-hood, industrial control, and aerospace environments |
| Tolerance | ±5% - specifies initial calibration accuracy without post-manufacturing trimming |
Pinout & Package
DO-35 glass axial package with cathode indicated by color band; two-terminal device requiring no external biasing or control signals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / reference ground node | Connected to circuit common or lower potential side in shunt configuration |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input voltage source and load; provides stable reference voltage relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic DO-35 glass package | Ensures long-term parameter stability and moisture resistance in harsh environments |
| 5% zener voltage tolerance | Reduces need for external trimming in mid-precision voltage reference applications |
| Low dynamic impedance (6.4 Ω) | Maintains tight regulation (<±0.1 V) under ±10 mA load variations at nominal current |
| High temperature rating (200°C) | Supports operation in engine control units, motor drives, and industrial power converters |
| Controlled leakage (≤0.25 μA) | Minimizes error in high-gain op-amp reference buffers and battery-monitoring circuits |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Used in optocoupler-coupled feedback loop of isolated AC/DC adapter to regulate 12 V output. IC Role / Device Role / Timing Role: Zener reference diode providing precise 44.65 V threshold to TL431-like shunt regulator IC. Use Value: Enables ±1% output voltage regulation via stable reference point unaffected by transformer leakage or line ripple. | Use Scenario: Placed across DC bus of 36 V industrial motor drive to prevent MOSFET overvoltage during regeneration. IC Role / Device Role / Timing Role: Passive clamping element diverting surge energy when bus exceeds 44.65 V. Use Value: Limits transient voltage to safe level below MOSFET VDSS rating without active control or delay. |
| Analog Signal Level Shifting | Temperature-Stable Reference Source |
Use Scenario: Biasing op-amp input stage in 4–20 mA transmitter to shift 0–5 V sensor output to 4–20 mA range. IC Role / Device Role / Timing Role: Precision DC reference establishing offset voltage for current-loop scaling. Use Value: Provides repeatable 44.65 V reference with <0.01%/°C drift contribution due to low ZZ and stable packaging. | Use Scenario: Serving as primary reference in oven-controlled crystal oscillator (OCXO) voltage control loop. IC Role / Device Role / Timing Role: Stable voltage source for DAC-based tuning voltage generation. Use Value: Delivers <10 ppm/°C effective TC due to matched thermal coefficient with series resistor network. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4753A | Same nominal voltage (47 V), but ±5% tolerance, higher ZZ (17 Ω), lower PD (1 W vs. 500 mW) | Higher power handling; less suitable for space-constrained PCBs where DO-35 size is critical | Select 1N4753A only if >500 mW dissipation is required and larger DO-41 package is acceptable |
| BZX55-C47 | 47 V nominal, ±5% tolerance, ZZ = 15 Ω @ 5 mA, different test current (5 mA vs. 105 mA) | Optimized for low-current references; not recommended for high-current shunt regulation | Choose BZX55-C47 for low-power biasing, not for 105 mA regulation duty cycles |
Compared with 1N4753A and BZX55-C47, the 1N977B_T50A offers tighter dynamic impedance at high test current and DO-35 form factor ideal for compact analog boards, while maintaining identical voltage tolerance and superior thermal range.
Availability
1N977B_T50A is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, analog signal conditioning, and temperature-stable reference designs requiring stable component supply and long-lifecycle support.
Supply support for 1N977B_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
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 standard family of general-purpose Zener diodes targeting cost-sensitive, high-reliability voltage reference and regulation tasks in industrial and consumer electronics.
FAQ
What is the nominal zener voltage of the 1N977B_T50A?
The 1N977B_T50A has a nominal zener voltage of 44.65 V, with a minimum of 44.65 V and maximum of 49.35 V at test current IZ = 105 mA. This value is specified per Fairchild's 1N957B–1N979B datasheet Rev. F1 and reflects the device's 5% tolerance band. The 1N977B_T50A achieves this regulation point under controlled thermal conditions (lead temperature ≤75°C).
What package type does the 1N977B_T50A use?
The 1N977B_T50A uses the DO-35 glass axial package, identified by a cathode color band and marked with "F" logo, "77", and "B" across three lines. This hermetically sealed package supports operation from -65°C to +200°C and is distinct from plastic DO-41 variants. The 1N977B_T50A's DO-35 form factor ensures low parasitic capacitance and long-term parameter stability.
What is the maximum power dissipation for the 1N977B_T50A?
The 1N977B_T50A has a maximum power dissipation of 500 mW at lead temperature ≤75°C, with linear derating of 4.0 mW/°C above that temperature. This rating is defined under standardized test conditions (3/8″ lead length) and directly constrains usable current in shunt regulator applications. Exceeding this limit risks thermal runaway or parametric shift in the 1N977B_T50A.
How does the 1N977B_T50A compare to the 1N4753A in terms of zener impedance?
The 1N977B_T50A has a zener impedance of 6.4 Ω at 105 mA, while the 1N4753A specifies 17 Ω at 21 mA. This lower impedance at higher current makes the 1N977B_T50A more effective for high-current regulation stability. The 1N977B_T50A's impedance advantage is most relevant in applications like SMPS feedback where load transients demand tight voltage control.
Is the 1N977B_T50A suitable for high-temperature environments?
Yes-the 1N977B_T50A is rated for operation from -65°C to +200°C, making it suitable for under-hood automotive, industrial motor controls, and downhole instrumentation. Its DO-35 glass package contributes to this extended range, and the 1N977B_T50A maintains specified electrical characteristics across this full span when operated within its power and current limits.
1N977B_T50A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Box (TB)
- 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_T50A FAQ
1.How can I place an order for 1N977B_T50A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N977B_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 1N977B_T50A reliable?
The price and inventory of 1N977B_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N977B_T50A is usually 5 days.
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1N977B_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N977B_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 1N977B_T50A?
For technical support, including 1N977B_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N977B_T50A requirements.
6.How does Aetrix verify that 1N977B_T50A is sourced from the original manufacturer or authorized distributors?
All 1N977B_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 1N977B_T50A meets industry standards.
7.What is the process for return or replacement of 1N977B_T50A?
All 1N977B_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N977B_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 1N977B_T50A part is unused and in its original packaging.
Return procedure for 1N977B_T50A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N977B_T50A Tags
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