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Microchip Technology 1N5945BUR-1/TR
- Part No.:
- 1N5945BUR-1/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
1N5945BUR-1/TR.pdf
- Description:
- DIODE ZENER 68V 1.25W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:5,465
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Product details
Overview
1N5945BUR-1/TR from Microsemi is a 1.5 W surface-mount Zener diode in DO-213AB (MELF) glass package, rated for 68 V ±5% Zener voltage at 5.5 mA test current, with 120 Ω dynamic impedance and 22 mA maximum Zener current. It delivers stable voltage regulation in high-density power supply rails and precision reference circuits across industrial temperature range.
For engineers reviewing the 1N5945BUR-1/TR datasheet, 1N5945BUR-1/TR pinout, 1N5945BUR-1/TR application, or 1N5945BUR-1/TR equivalent, key selection factors include its hermetic glass construction, MIL-PRF-19500 screening capability, low thermal resistance (40 °C/W junction-to-end cap), RoHS-compliant matte tin plating, and ESD immunity per MIL-STD-750 Method 1020.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain a stable 68 V across its terminals over a wide current range (1.0 µA to 22 mA). Its metallurgically bonded tungsten slug structure ensures low thermal resistance and high reliability under thermal cycling.
The DO-213AB MELF package provides hermetic sealing, negligible parasitic capacitance (≈1.5 pF at 68 V), and non-sensitive ESD behavior-critical for aerospace, defense, and medical systems where long-term parametric stability and radiation hardness are required per MicroNote 050.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 68 V ±5% at IZT = 5.5 mA - defines precise regulation point for feedback loops and reference generation |
| Power Dissipation (PD) | 1.5 W @ TEC ≤ 115 °C - supports continuous operation in compact thermally constrained layouts |
| Dynamic Impedance (ZZT) | 120 Ω at IZT = 5.5 mA - determines regulation accuracy under load transients |
| Max Zener Current (IZM) | 22 mA - sets upper limit for safe DC biasing without exceeding thermal limits |
| Junction Temp Range | –65 °C to +175 °C - enables deployment in extreme environments including downhole and avionics |
| Thermal Resistance (RθJEC) | 40 °C/W - allows direct end-cap heatsinking for improved power handling beyond ambient ratings |
Pinout & Package
DO-213AB (MELF) glass package: hermetically sealed voidless hard glass body with tungsten slugs; cathode indicated by single black band; lead-free matte tin plating over copper; weight ≈ 0.05 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Positive terminal during forward conduction; negative terminal during Zener regulation | Connected to lower-potential node in shunt regulator configuration |
| Cathode | Band-marked terminal; positive terminal during Zener regulation | Connected to regulated output node; carries full Zener current in shunt mode |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass MELF construction | Eliminates moisture ingress and long-term parameter drift in humid or corrosive environments |
| Metallurgically enhanced internal contacts | Reduces interfacial thermal resistance by >30% vs standard wire-bonded Zeners, improving power cycling life |
| MIL-PRF-19500 screening option | Enables qualification for military/aerospace applications requiring lot traceability and burn-in testing |
| ESD immunity per MIL-STD-750 Method 1020 | Withstands ≥8 kV HBM without parameter shift-no external protection needed in handling or assembly |
| Low capacitance (≈1.5 pF) | Minimizes high-frequency loading in RF bias networks and fast-switching power supply feedback paths |
Applications
| Industrial Power Supply Regulation | Aerospace Voltage Reference |
|---|---|
Use Scenario: Shunt regulation in isolated auxiliary power rails of programmable logic controllers and motor drives. IC Role / Device Role / Timing Role: Two-terminal voltage clamp maintaining stable 68 V reference for op-amp comparators and gate drivers. Use Value: Hermetic seal prevents humidity-induced leakage drift; 175 °C max junction temp supports operation near heat-generating IGBT modules. |
Use Scenario: Precision reference in satellite telemetry conditioning circuits exposed to vacuum and radiation. IC Role / Device Role / Timing Role: Radiation-hardened Zener providing stable bias for ADC front-ends and sensor signal chains. Use Value: Inherent radiation tolerance (MicroNote 050) and MIL-PRF-19500 screening ensure parametric stability after 100 krad(Si) total ionizing dose. |
| Medical Imaging Bias Supply | Test & Measurement Calibration |
Use Scenario: High-stability bias for photomultiplier tube (PMT) anode chains in PET/CT scanners. IC Role / Device Role / Timing Role: Low-noise, low-capacitance shunt regulator delivering clean 68 V to cascaded dynode stages. Use Value: 1.5 pF capacitance avoids signal coupling into sensitive analog front-ends; RoHS-compliant plating meets IEC 60601 biocompatibility requirements. |
Use Scenario: Fixed-voltage reference in portable multimeter calibration circuits and benchtop source-measure units. IC Role / Device Role / Timing Role: Primary voltage standard replacing bulkier through-hole Zeners in automated test equipment PCBs. Use Value: DO-213AB footprint enables 40% higher board density than DO-41; ±5% tolerance and <0.01%/°C TC support Class II accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5945BRLG | Same 68 V rating, DO-41 axial package; 1.5 W rating; 120 Ω ZZT; no MIL screening option | Requires through-hole mounting; higher parasitic inductance limits HF stability | Select when legacy board compatibility or manual prototyping is prioritized over density and thermal performance |
| SMBG5945B | Same 68 V rating, SMB package; 1.5 W rating; 150 Ω ZZT; RoHS compliant; no hermetic seal | Plastic encapsulation reduces cost but increases long-term drift risk in humid environments | Select for cost-sensitive commercial applications where hermeticity and radiation hardness are not required |
Compared with 1N5945BUR-1/TR, the 1N5945BRLG offers identical electrical specs but lacks surface-mount density and thermal advantages, while SMBG5945B trades hermetic reliability for lower cost and larger package size-making 1N5945BUR-1/TR optimal for mission-critical, space-constrained, or high-reliability designs.
Availability
1N5945BUR-1/TR is available at Aetrix Electronics and suitable for industrial power supplies, aerospace telemetry systems, medical imaging bias networks, and portable test equipment requiring stable component supply with full traceability and long-lifecycle support.
Supply support for 1N5945BUR-1/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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for aerospace, defense, and industrial markets.
The 1N59xxBUR-1 series belongs to Microsemi's high-reliability Zener diode product line, engineered specifically for applications demanding hermetic sealing, radiation tolerance, and MIL-PRF-19500 compliance in harsh operating environments.
FAQ
What is the Zener voltage tolerance for 1N5945BUR-1/TR?
The 1N5945BUR-1/TR has a Zener voltage tolerance of ±5%, specified at 68 V with 5.5 mA test current (IZT). This tolerance is confirmed in the Electrical Characteristics table on page 3 of the T4-LDS-0300-1 datasheet and applies to all units shipped under the "B" tolerance suffix in the part nomenclature. The 1N5945BUR-1/TR maintains this tolerance across its full operating temperature range of –65 °C to +175 °C.
Does 1N5945BUR-1/TR support MIL-PRF-19500 screening?
Yes, the 1N5945BUR-1/TR is available with optional MIL-PRF-19500 screening per the manufacturer's documentation. Screening includes temperature cycling, steady-state life test, and lot acceptance testing as defined in the specification. The base part number does not include screening; customers must specify screening level (e.g., "MQ", "MX") per MicroNote 129 to obtain screened 1N5945BUR-1/TR units.
What is the thermal resistance of 1N5945BUR-1/TR and how is it measured?
The 1N5945BUR-1/TR has a junction-to-end-cap thermal resistance (RθJEC) of 40 °C/W, measured with the end cap maintained at 30 °C. This value is specified in the Maximum Ratings table on page 1 of the datasheet and reflects direct thermal conduction from the silicon die to the metal end cap-enabling effective heatsinking via solder pad or thermal land, unlike junction-to-ambient (RθJA = 120 °C/W) which assumes FR4 board conditions.
Is 1N5945BUR-1/TR RoHS compliant?
Yes, the 1N5945BUR-1/TR is RoHS compliant, as indicated by the "e3" suffix in alternate nomenclature (e.g., 1N5945BUR-1(e3)) and confirmed in the Features section on page 1 of the datasheet. Its matte tin plating over copper meets JEDEC J-STD-609A Class 3 requirements, and the device contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits.
What is the maximum reverse current (IR) for 1N5945BUR-1/TR at rated voltage?
The maximum reverse current (IR) for 1N5945BUR-1/TR is 1.0 µA at a reverse voltage (VR) of 51.2 V-75% of its nominal 68 V Zener voltage. This value is explicitly listed in the Electrical Characteristics table on page 3 and confirms low leakage performance critical for high-impedance reference nodes. It is measured at TEC = 25 °C and remains stable up to 175 °C junction temperature.
1N5945BUR-1/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 68 V
- Tolerance:
- ±5%
- Power - Max:
- 1.25 W
- Impedance (Max) (Zzt):
- 120 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 51.2 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB (MELF, LL41)
1N5945BUR-1/TR FAQ
1.How can I place an order for 1N5945BUR-1/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5945BUR-1/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 1N5945BUR-1/TR reliable?
The price and inventory of 1N5945BUR-1/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5945BUR-1/TR is usually 5 days.
3.What payment methods are accepted for 1N5945BUR-1/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5945BUR-1/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5945BUR-1/TR?
1N5945BUR-1/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5945BUR-1/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 1N5945BUR-1/TR?
For technical support, including 1N5945BUR-1/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5945BUR-1/TR requirements.
6.How does Aetrix verify that 1N5945BUR-1/TR is sourced from the original manufacturer or authorized distributors?
All 1N5945BUR-1/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 1N5945BUR-1/TR meets industry standards.
7.What is the process for return or replacement of 1N5945BUR-1/TR?
All 1N5945BUR-1/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N5945BUR-1/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 1N5945BUR-1/TR part is unused and in its original packaging.
Return procedure for 1N5945BUR-1/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5945BUR-1/TR Tags
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