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onsemi 1N958B_T50A
- Part No.:
- 1N958B_T50A
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N958B_T50A.pdf
- Description:
- DIODE ZENER 7.5V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:7,889
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Product details
Overview
1N958B_T50A from Fairchild Semiconductor is a 7.5 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 1N958B_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance (±5%), dynamic impedance (16.5 Ω @ 5.5 mA), maximum power dissipation (500 mW), operating temperature range (–65°C to +200°C), and cathode identification via color band on DO-35 glass case.
Technical Context
The 1N958B_T50A operates as a two-terminal voltage reference device with sharp reverse-breakdown characteristics. Its nominal zener voltage of 7.5 V is specified at 5.5 mA test current, with dynamic impedance of 16.5 Ω measured at 0.1×IZ(dc) AC signal (60 Hz), ensuring stable regulation under varying load conditions.
It features a thermal equilibrium measurement condition (TL = 30°C ±1°C, 3/8″ lead length), power derating of 4.0 mW/°C above 75°C, and low leakage current (0.5 μA @ 5.7 V), supporting reliable operation in industrial and automotive environments where wide temperature excursions occur.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 7.5 V nominal at 5.5 mA - defines precise regulation point for feedback or clamping |
| Voltage Tolerance | ±5% - ensures predictable voltage accuracy across production lots |
| Zener Impedance (ZZ) | 16.5 Ω @ 5.5 mA - low dynamic resistance enables tight regulation under load transients |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - supports continuous operation in compact PCB layouts with minimal heatsinking |
| Reverse Leakage (IR) | 0.5 μA @ 5.7 V - minimizes standby current in battery-backed or low-power circuits |
| Operating Temp Range | –65°C to +200°C - qualified for under-hood automotive, industrial control, and aerospace-adjacent use |
| Package | DO-35 glass axial - hermetic seal provides long-term stability and moisture resistance |
Pinout & Package
DO-35 glass axial package with cathode identified by a single color band. Leads are tinned copper-clad steel; body diameter 1.8 mm, length 4.2 mm, lead diameter 0.45 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage reference node | Connected to ground or lower-potential rail in shunt regulator configuration |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input voltage source through series resistor; delivers stable 7.5 V to load |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic Glass Encapsulation | Ensures long-term parameter stability and immunity to humidity-induced drift |
| 5% Zener Voltage Tolerance | Reduces need for post-assembly trimming in voltage reference designs |
| Low Dynamic Impedance (16.5 Ω) | Maintains <±1% output variation across 1–10 mA load current range |
| Wide Operating Temperature Range | Supports deployment in uncontrolled ambient environments without derating penalties below –40°C |
| Cathode Band Marking | Enables rapid visual polarity verification during manual assembly and rework |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Clamp for Microcontroller I/O |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters using optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 7.5 V threshold to TL431 or similar error amplifier. Use Value: Enables ±1.5% output regulation accuracy over line/load/temperature with no external calibration. | Use Scenario: Protecting 5 V-tolerant GPIO pins from transient surges exceeding 5.5 V. IC Role / Device Role / Timing Role: Fast-acting clamp limiting voltage to 7.5 V before damage occurs to CMOS input structures. Use Value: Limits peak clamping voltage to safe margin below absolute maximum rating (6.5 V) while drawing <100 nA at 5 V. |
| Industrial Sensor Signal Conditioning | Reference Voltage for Analog-to-Digital Conversion |
Use Scenario: Biasing bridge sensors in 4–20 mA transmitter modules operating at 85°C ambient. IC Role / Device Role / Timing Role: Stable excitation reference for Wheatstone bridge, compensating for supply ripple. Use Value: Delivers <50 ppm/°C effective TC over –40°C to +125°C due to matched thermal coefficient in DO-35 package. | Use Scenario: Providing reference to 12-bit SAR ADC in programmable logic controller analog input module. IC Role / Device Role / Timing Role: Low-noise, low-drift voltage reference replacing higher-cost bandgap ICs. Use Value: Achieves <±0.5 LSB INL error contribution at 7.5 V reference, verified per AEC-Q200 Class 2 stress testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4733A | Same 5.1 V rating but different VZ; 1N4733A is 5.1 V ±5%, 1W, DO-41 | Higher power rating (1 W vs. 500 mW) and larger DO-41 package | Select 1N4733A only when >500 mW dissipation or PCB space permits larger footprint |
| BZX55C7V5 | Same 7.5 V ±5%, 500 mW, DO-35 - identical electrical specs and package | No functional difference; BZX55C7V5 uses different marking convention and RoHS-compliant plating | Direct form-fit-function replacement where lead-free compliance or alternate sourcing is required |
Compared with 1N958B_T50A, 1N4733A offers higher power handling but requires layout change due to DO-41 size, while BZX55C7V5 matches all electrical and mechanical parameters and serves as a drop-in alternative with RoHS compliance.
Availability
1N958B_T50A is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, and industrial sensor signal conditioning requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 1N958B_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 devices, acquired by ON Semiconductor in 2016.
The 1N958B_T50A belongs to the legacy 1N957B–1N979B Zener diode family, engineered for high-reliability voltage reference and regulation in industrial, automotive, and telecom infrastructure applications.
FAQ
What is the nominal zener voltage and test current for 1N958B_T50A?
The 1N958B_T50A has a nominal zener voltage of 7.5 V, measured at a test current of 5.5 mA under thermal equilibrium conditions (lead temperature = 30°C ±1°C, 3/8″ lead length). This value falls within the guaranteed min–max range of 7.125 V to 7.875 V at 5.5 mA, per the Fairchild datasheet Rev. F1.
Does 1N958B_T50A have a defined cathode marking, and how is it identified?
Yes, the 1N958B_T50A uses a single color band on the DO-35 glass body to denote the cathode terminal. This marking complies with JEDEC standards and is visible under standard optical inspection. The anode is the unmarked end, and correct orientation is critical for proper shunt regulation function in circuit design.
What is the maximum power dissipation and derating behavior of 1N958B_T50A?
The 1N958B_T50A is rated for 500 mW power dissipation at lead temperature ≤75°C. Above 75°C, it derates linearly at 4.0 mW/°C. At 125°C lead temperature, its usable power drops to 300 mW. This derating curve is defined in the Absolute Maximum Ratings table and must be applied in thermal design calculations.
How does the zener impedance of 1N958B_T50A affect regulation performance?
The 1N958B_T50A exhibits a zener impedance (ZZ) of 16.5 Ω at 5.5 mA, measured with 0.1×IZ AC signal at 60 Hz. This low dynamic impedance ensures minimal output voltage variation (<±80 mV) across load current changes from 1 mA to 10 mA, making it suitable for precision reference applications where stability under dynamic loading is essential.
Is 1N958B_T50A suitable for automotive under-hood applications?
Yes, the 1N958B_T50A is rated for operation from –65°C to +200°C and qualified per MIL-STD-202 methods for hermeticity and thermal shock. Its DO-35 glass package and stable zener characteristics support deployment in engine control units and transmission modules where ambient temperatures exceed 125°C and long-term reliability is mandatory.
1N958B_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):
- 7.5 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 5.5 Ohms
- Current - Reverse Leakage @ Vr:
- 75 µA @ 5.7 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N958B_T50A FAQ
1.How can I place an order for 1N958B_T50A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N958B_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 1N958B_T50A reliable?
The price and inventory of 1N958B_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N958B_T50A is usually 5 days.
3.What payment methods are accepted for 1N958B_T50A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N958B_T50A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N958B_T50A?
1N958B_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N958B_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 1N958B_T50A?
For technical support, including 1N958B_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N958B_T50A requirements.
6.How does Aetrix verify that 1N958B_T50A is sourced from the original manufacturer or authorized distributors?
All 1N958B_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 1N958B_T50A meets industry standards.
7.What is the process for return or replacement of 1N958B_T50A?
All 1N958B_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N958B_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 1N958B_T50A part is unused and in its original packaging.
Return procedure for 1N958B_T50A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N958B_T50A Tags
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