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Microchip Technology 1N2994RB
- Part No.:
- 1N2994RB
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-203AA, DO-4, Stud
- Datasheet:
-
1N2994RB.pdf
- Description:
- DIODE ZENER 45V 10W DO4
- Quantity:
- Payment:
- Shipping:
Inventory:6,346
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Product details
Overview
1N2994RB from Microsemi is a 10 W, 45 V, ±5% tolerance hermetically sealed Zener diode in DO-213AA (DO-4) metal-glass stud package with reverse polarity (cathode-to-stud). It delivers stable voltage regulation across -65°C to +175°C junction temperature, supports 400 mA maximum Zener current at 25°C, and exhibits 55 Ω dynamic impedance at 13 mA test current. Used in high-reliability power supply reference and overvoltage protection circuits in aerospace and defense systems.
For engineers reviewing the 1N2994RB datasheet, 1N2994RB pinout, 1N2994RB application, or 1N2994RB equivalent, this page provides verified military-grade Zener specifications, DO-4 mechanical interface details, thermal derating guidance, MIL-PRF-19500/124 qualification status, and validated alternative part options for ruggedized voltage regulation designs.
Technical Context
This device operates as a precision voltage reference in the reverse breakdown region, with Zener voltage specified at 45 V ±5% under 13 mA test current (IZT). Its hermetically sealed DO-4 package enables operation up to +175°C junction temperature and ensures immunity to humidity, contaminants, and ESD per MIL-STD-750 Method 1020.
Thermal resistance is fixed at 12°C/W (junction-to-case), requiring mechanical mounting to a heatsink or chassis for full 10 W power dissipation at TC = +55°C. Derating follows 0.083 W/°C above +55°C, and maximum reverse leakage is 10 µA at 33.0 V (VR).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 45 V ±5% at 13 mA - defines nominal regulation point with tight tolerance for reference stability |
| Power Dissipation (PD) | 10 W @ TC = +55°C - requires direct thermal path to chassis; derates linearly above +55°C |
| Zener Test Current (IZT) | 13 mA - standardized bias point for VZ and ZZT measurement; sets operating point for regulation accuracy |
| Dynamic Impedance (ZZT) | 55 Ω @ IZT - low AC impedance ensures minimal output voltage variation under dynamic load changes |
| Junction Temperature Range | -65°C to +175°C - enables deployment in extreme environments including space and engine bays |
| Reverse Leakage (IR) | 10 µA @ 33.0 V - confirms low off-state conduction for reliable clamping and reference integrity |
| Thermal Resistance (RθJC) | 12°C/W - quantifies thermal bottleneck; mandates stud-mounting to metal surface for heat extraction |
Pinout & Package
Package: DO-213AA (DO-4), hermetically sealed metal-glass stud package with 10-32 UNF–2A threaded stud (anode terminal), flat hex body (0.424″ max diameter), and tin-lead or matte-tin plating on nickel. Weight ≈ 7.5 g. Mounting requires nut torque ≤15 in-lb.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Stud (Threaded Body) | Cathode | Primary heat sink interface and electrical connection; reverse polarity configuration per "RB" suffix |
| Top Cap / Dome | Anode | Secondary solderable terminal; must be electrically isolated from chassis when stud is grounded |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic metal-glass seal | Prevents moisture ingress and outgassing-critical for long-term reliability in vacuum or high-humidity mil-aero applications |
| MIL-PRF-19500/124 qualification | JAN/JANTX/JANTXV screening available-ensures radiation hardness, burn-in, and environmental stress testing compliance |
| Internal solder bond construction | Eliminates wire bonds-reduces failure modes under thermal cycling and mechanical shock |
| Nonsensitive to ESD | Qualified per MIL-STD-750 Method 1020-enables handling without special static controls in production environments |
| Inherent radiation hardness | Validated per Microsemi MicroNote 050-supports use in satellite power systems and nuclear instrumentation |
Applications
| Aerospace Power Reference | Defense System Overvoltage Clamp |
|---|---|
Use Scenario: Primary voltage reference in DC-DC converter feedback loop of satellite power management unit. IC Role / Device Role / Timing Role: Zener diode providing stable 45 V reference for error amplifier input. Use Value: ±5% tolerance and <12°C/W thermal resistance ensure regulation stability across -65°C to +125°C orbit temperature swings. |
Use Scenario: Overvoltage protection clamp on 28 V aircraft bus during load dump transients. IC Role / Device Role / Timing Role: Crowbar element shunting excess energy to chassis ground via stud mount. Use Value: 10 W power rating and 175°C junction limit allow sustained clamping without thermal runaway during 100 ms surges. |
| Industrial Motor Drive Bias Supply | Nuclear Instrumentation Reference |
Use Scenario: Isolated +45 V bias rail for gate drivers in high-voltage IGBT stacks. IC Role / Device Role / Timing Role: Precision Zener regulating auxiliary supply independent of main bus fluctuations. Use Value: 55 Ω dynamic impedance minimizes ripple coupling into sensitive gate drive circuitry. |
Use Scenario: Calibration reference in radiation-hardened neutron detector front-end. IC Role / Device Role / Timing Role: Stable voltage standard for ADC reference divider network. Use Value: Inherent radiation hardness and hermetic seal prevent parameter drift under gamma/neutron flux exposure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N2994B | Same 45 V, 10 W rating but standard polarity (anode-to-stud); 55 Ω ZZT identical; same DO-4 package | Requires reversed PCB layout and mounting orientation; incompatible with cathode-grounded topologies | Select 1N2994B only if anode-to-stud polarity matches existing mechanical and schematic design |
| 1N3000B | 62 V nominal Zener voltage; otherwise identical DO-4 package, 10 W rating, and MIL-PRF-19500/124 qualification | Suitable for higher-voltage reference or clamp circuits; not interchangeable without circuit revalidation | Choose 1N3000B when system requires 62 V regulation and can accommodate revised feedback or threshold design |
Compared with 1N2994B and 1N3000B, the 1N2994RB offers unique cathode-to-stud polarity in a hermetically sealed, radiation-hardened 45 V Zener-making it irreplaceable in chassis-grounded cathode configurations where polarity and reliability are non-negotiable.
Availability
1N2994RB is available at Aetrix Electronics and suitable for aerospace power references, defense system overvoltage clamps, and nuclear instrumentation requiring stable component supply with full traceability and long-term obsolescence mitigation.
Supply support for 1N2994RB 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and military-qualified analog and mixed-signal components.
The 1N2994RB belongs to Microsemi's legacy MIL-PRF-19500/124 qualified Zener diode family, engineered for voltage regulation in mission-critical aerospace, defense, and nuclear systems where hermeticity and thermal robustness are mandatory.
FAQ
What does the "RB" suffix mean in 1N2994RB?
The "RB" suffix in 1N2994RB denotes reverse polarity: cathode is connected to the threaded stud, while the anode is at the top cap. This differs from the standard 1N2994B (anode-to-stud) and affects PCB layout, grounding scheme, and mounting orientation in chassis-grounded systems.
Is 1N2994RB qualified to MIL-PRF-19500/124?
Yes, the 1N2994RB is available in JAN, JANTX, and JANTXV reliability levels per MIL-PRF-19500/124. These qualifications include rigorous environmental stress screening, burn-in, and radiation hardness validation-confirmed in Microsemi document T4-LDS-0075 Rev. 3.
What is the maximum steady-state power dissipation for 1N2994RB?
The 1N2994RB has a rated steady-state power dissipation of 10 W at case temperature (TC) = +55°C. Above +55°C, it must be derated linearly at 0.083 W/°C, reaching zero dissipation at +175°C-matching its absolute maximum junction temperature rating.
Can 1N2994RB be surface mounted?
No, the 1N2994RB uses a DO-213AA (DO-4) hermetically sealed stud package designed exclusively for through-hole chassis mounting. Microsemi explicitly states that surface mount equivalents require factory consultation-no SMT variant exists for this part number.
What is the Zener impedance of 1N2994RB and why does it matter?
The 1N2994RB has a dynamic impedance (ZZT) of 55 Ω measured at 13 mA Zener test current. This value determines how much the output voltage varies under changing load current-lower ZZT means tighter regulation, critical for precision reference and low-noise bias applications.
1N2994RB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-203AA, DO-4, Stud
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 45 V
- Tolerance:
- ±5%
- Power - Max:
- 10 W
- Impedance (Max) (Zzt):
- 13 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 33 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 2 A
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Stud Mount
- Supplier Device Package:
- DO-4 (DO-203AA)
1N2994RB FAQ
1.How can I place an order for 1N2994RB through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N2994RB 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 1N2994RB reliable?
The price and inventory of 1N2994RB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N2994RB is usually 5 days.
3.What payment methods are accepted for 1N2994RB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N2994RB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N2994RB?
1N2994RB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N2994RB 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 1N2994RB?
For technical support, including 1N2994RB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N2994RB requirements.
6.How does Aetrix verify that 1N2994RB is sourced from the original manufacturer or authorized distributors?
All 1N2994RB 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 1N2994RB meets industry standards.
7.What is the process for return or replacement of 1N2994RB?
All 1N2994RB units undergo pre-shipment inspection (PSI). If there is an issue with 1N2994RB, 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 1N2994RB part is unused and in its original packaging.
Return procedure for 1N2994RB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N2994RB Tags
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