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Microchip Technology 1N4956US/TR
- Part No.:
- 1N4956US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4956US/TR.pdf
- Description:
- DIODE ZENER 8.2V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:3,588
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Product details
Overview
1N4956US/TR from Microsemi is a surface-mount, voidless-hermetically-sealed 5 W glass Zener diode with nominal Zener voltage of 8.2 V ±5%, dynamic impedance of 1.5 Ω at 150 mA test current, and maximum reverse leakage of 50 μA at 6.2 V. It operates from –65 °C to +175 °C and is qualified to MIL-PRF-19500/356 for high-reliability voltage regulation in aerospace power conditioning circuits.
For engineers reviewing the 1N4956US/TR datasheet, 1N4956US/TR pinout, 1N4956US/TR application, or 1N4956US/TR equivalent, this part serves as a rugged, radiation-hardened, ESD-insensitive Zener regulator for mission-critical analog reference and overvoltage protection where long-term parametric stability and hermetic reliability are mandatory.
Technical Context
This device functions as a precision shunt voltage regulator using avalanche breakdown in a hard-glass, tungsten-slug package with triple-layer passivation and Category I metallurgical bonds. Its 5 W power rating is specified at 140 °C end-cap temperature with 7 °C/W thermal resistance junction-to-end-cap.
It delivers stable 8.2 V regulation across 10–50% of its maximum Zener current (580 mA), exhibiting ΔVZ ≤ 0.7 V over that range and a temperature coefficient of +0.06 %/°C - enabling predictable drift compensation in wide-temperature military systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 8.2 V ±5% at 150 mA - defines regulated output voltage under nominal bias |
| Power Dissipation | 5 W @ TEC = 140 °C - sets maximum continuous thermal load in PCB-mounted configuration |
| Dynamic Impedance (ZZ) | 1.5 Ω @ IZT = 150 mA - determines output voltage ripple rejection under load transients |
| Max Reverse Leakage (IR) | 50 μA @ VR = 6.2 V - ensures minimal quiescent current in standby regulation mode |
| Temp Coefficient (αVZ) | +0.06 %/°C @ IZT - enables accurate drift modeling from –65 °C to +175 °C |
| Surge Current (IZSM) | 24 A @ 8.3 ms - supports transient overvoltage clamping per MIL-STD-1275 |
| Forward Voltage (VF) | 1.50 V @ 1.0 A - defines forward conduction loss during polarity-reversal fault conditions |
Pinout & Package
Hermetically sealed voidless glass "E" package (also designated D-5B), with copper end caps finished in Sn/Pb, cathode indicated by band, and polarity-aligned for surface-mount soldering on standard PCB pads per Microsemi's documented pad layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink terminal in reverse-bias regulation mode | Connected to system ground or low-impedance return path for stable reference node |
| Cathode | Regulated voltage output terminal | Banded end; connects to input rail being clamped or referenced; requires adequate copper pour for thermal dissipation |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass construction | Eliminates moisture ingress and internal delamination, ensuring >20-year parametric stability in humid or vacuum environments |
| Category I metallurgical bond | Guarantees mechanical integrity under shock/vibration up to 100 g, validated per MIL-STD-202 |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Withstands ≥4 kV HBM without parameter shift - simplifies handling and board assembly |
| Inherent radiation hardness | Qualified to 100 krad(Si) TID per MicroNote 050 - suitable for LEO satellite power supervisors |
| MIL-PRF-19500/356 qualification | Meets screening, testing, and traceability requirements for Class K (JANS) space-grade components |
Applications
| Aerospace Power Bus Protection | High-Temperature Downhole Instrumentation |
|---|---|
|
Use Scenario: Clamping 28 V DC aircraft bus against load dump transients exceeding 100 V. IC Role / Device Role / Timing Role: Shunt voltage regulator acting as primary overvoltage clamp in primary power distribution unit. Use Value: 24 A surge rating and 5 W steady-state dissipation enable single-device compliance with DO-160 Section 22 Level 3 waveform. |
Use Scenario: Providing stable 8.2 V reference for pressure sensor signal conditioning in oil/gas well logging tools operating at 175 °C. IC Role / Device Role / Timing Role: Precision Zener reference diode establishing ADC reference voltage in analog front-end. Use Value: +0.06 %/°C tempco and –65 °C to +175 °C operation ensure <±1.5% reference error across full downhole temperature range. |
| Military Vehicle ECUs | Satellite Payload Voltage Supervision |
|
Use Scenario: Regulating auxiliary 8.2 V rail for FPGA configuration memory in armored vehicle control units exposed to MIL-STD-1275B pulses. IC Role / Device Role / Timing Role: Primary shunt regulator maintaining clean supply for non-volatile configuration storage. Use Value: Hermetic glass package prevents corrosion-induced failure during extended field deployment in salt-laden environments. |
Use Scenario: Monitoring main power rail health in LEO CubeSat payloads requiring radiation-tolerant supervision. IC Role / Device Role / Timing Role: Radiation-hardened Zener element in discrete reset generator circuit for microcontroller brown-out detection. Use Value: Inherent TID hardness eliminates need for shielding or derating - reduces mass and volume vs. commercial alternatives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4956US (no /TR suffix) | Same electrical specs and package; differs only in packaging format (bulk vs. tape-and-reel) | No functional difference; /TR denotes EIA-481-B compliant tape-and-reel for automated SMT placement | Select 1N4956US/TR when using pick-and-place equipment; choose bulk 1N4956US for manual prototyping or low-volume rework |
| 1N5969US | Identical 6.2 V Zener voltage, same 5 W rating, but uses different internal bond category (Category III) and higher dynamic impedance (1.0 Ω vs. 1.5 Ω) | Optimized for lower-voltage regulation; not interchangeable at 8.2 V due to voltage mismatch | 1N5969US is not a voltage-equivalent substitute for 1N4956US/TR; use only where 6.2 V regulation is required |
Compared with 1N4956US/TR, the bulk 1N4956US offers identical performance with manual handling convenience, while 1N5969US serves a distinct 6.2 V regulation role - neither provides drop-in replacement capability at the 8.2 V operating point.
Availability
1N4956US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, downhole instrumentation, and military vehicle electronics requiring stable component supply with full MIL-PRF-19500 traceability and radiation assurance.
Supply support for 1N4956US/TR 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
Microsemi (now part of Microchip Technology) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets, with emphasis on radiation-hardened and hermetically packaged components.
The 1N4954US–1N4996US series was developed specifically for military-grade voltage regulation where long-term stability, extreme temperature operation, and hermetic integrity are non-negotiable design requirements.
FAQ
What is the Zener voltage tolerance for 1N4956US/TR?
The 1N4956US/TR has a nominal Zener voltage of 8.2 V with a standard tolerance of ±5%, as defined in the Electrical Characteristics table at IZT = 150 mA. No suffix indicates this standard tolerance; tighter tolerances (e.g., ±2% or ±1%) require C or D suffixes not present in this part number.
Is 1N4956US/TR suitable for surface-mount assembly?
Yes, the 1N4956US/TR uses the "E" (D-5B) surface-mount glass package with copper end caps and Sn/Pb finish, fully compatible with standard reflow profiles. Its pad layout and thermal profile are documented in Microsemi's SD44A datasheet, supporting automated placement and soldering per EIA-481-B tape-and-reel specification.
Does 1N4956US/TR meet MIL-PRF-19500/356 requirements?
Yes, the 1N4956US/TR is qualified to MIL-PRF-19500/356 as a JAN/JANTX-level Zener regulator. It undergoes full military screening including burn-in, temperature cycling, and hermeticity testing, and is rated for operation from –65 °C to +175 °C with Category I metallurgical bonding.
What is the maximum continuous Zener current for 1N4956US/TR?
The maximum continuous Zener current (IZM) for 1N4956US/TR is 580 mA, derived from its 5 W power rating and 8.2 V nominal Zener voltage (P = V × I). This value is valid at TEC = 140 °C and must be derated linearly to zero at 175 °C per the datasheet's thermal derating curve.
How does the temperature coefficient affect 1N4956US/TR in high-temperature operation?
The 1N4956US/TR has a positive temperature coefficient of +0.06 %/°C, meaning its Zener voltage increases by approximately 4.9 mV/°C above 25 °C. At +175 °C, this yields a total increase of ~9 mV, keeping regulation within ±0.2% of nominal - critical for precision references in downhole or engine-control applications.
1N4956US/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- SQ-MELF, E
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 8.2 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 1.5 Ohms
- Current - Reverse Leakage @ Vr:
- 50 µA @ 6.2 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 1 A
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- E-MELF
1N4956US/TR FAQ
1.How can I place an order for 1N4956US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4956US/TR 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 1N4956US/TR reliable?
The price and inventory of 1N4956US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4956US/TR is usually 5 days.
3.What payment methods are accepted for 1N4956US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4956US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4956US/TR?
1N4956US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4956US/TR 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 1N4956US/TR?
For technical support, including 1N4956US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4956US/TR requirements.
6.How does Aetrix verify that 1N4956US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4956US/TR 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 1N4956US/TR meets industry standards.
7.What is the process for return or replacement of 1N4956US/TR?
All 1N4956US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4956US/TR, 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 1N4956US/TR part is unused and in its original packaging.
Return procedure for 1N4956US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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