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Microchip Technology 1N4739UR/TR
- Part No.:
- 1N4739UR/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
1N4739UR/TR.pdf
- Description:
- DIODE ZENER 9.1V 1W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,883
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Product details
Overview
1N4739UR/TR from Microsemi is a surface-mount 1.0 W glass-encapsulated Zener diode with nominal Zener voltage 9.1 V, ±5% tolerance (A-suffix), 5.0 Ω dynamic impedance at 28 mA test current, and maximum reverse leakage of 7 μA at 7.3 V. It operates from –65°C to +175°C and is used for precision voltage regulation in high-density power supply rails and reference circuits.
For engineers reviewing the 1N4739UR/TR datasheet, 1N4739UR/TR pinout, 1N4739UR/TR application, or 1N4739UR/TR equivalent, key selection criteria include its DO-213AB MELF package, hermetic glass construction, low parasitic capacitance, radiation hardness per MicroNote 050, and suitability for high-reliability industrial and aerospace voltage reference designs.
Technical Context
This device functions as a two-terminal voltage regulator by operating in reverse breakdown, maintaining stable output voltage across a broad current range (0.5 mA to 500 mA) and temperature extremes. Its Zener knee occurs at 0.5 mA with 4.5 Ω impedance, ensuring sharp regulation onset and low noise performance.
The DO-213AB glass MELF package provides hermetic sealing, ESD insensitivity, and thermal resistance of 130°C/W on FR4 (1 oz Cu), enabling reliable operation without derating up to 45°C ambient or 125°C end-cap temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 9.1 V ±5% - precise regulation point for 9 V rail stabilization and analog reference generation |
| Power Dissipation | 1.0 W at TEC < 125°C - supports continuous operation in compact thermal environments |
| Dynamic Impedance (ZZT) | 5.0 Ω @ IZT = 28 mA - ensures minimal output voltage variation under load transients |
| Reverse Leakage Current | 7 μA @ VR = 7.3 V - guarantees low quiescent current in battery-backed or low-power systems |
| Operating Temperature | –65°C to +175°C - qualified for extended-range industrial, automotive, and downhole applications |
| Forward Voltage | 1.2 V max @ 200 mA - enables use as clamping diode in bidirectional protection schemes |
| Thermal Resistance | 130°C/W junction-to-ambient on FR4 - defines minimum PCB copper area and layout for thermal compliance |
Pinout & Package
Package: DO-213AB glass MELF - hermetically sealed, leadless, cylindrical surface-mount package with cathode band marking; dimensions A = 2.39–2.66 mm, B = 4.80–5.20 mm, C = 0.41–0.55 mm; weight 0.05 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Zener anode connection in reverse-bias configuration | Must be held at higher potential than anode to enable Zener conduction; polarity critical for regulation |
| Anode (unbanded end) | Zener cathode connection in reverse-bias configuration | Connected to system ground or lower-potential node; forms reference return path |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass MELF construction | Eliminates moisture ingress and long-term parameter drift; supports MIL-PRF-19500 screening options |
| Radiation hardness (MicroNote 050) | Enables use in space-grade and nuclear instrumentation without additional shielding or derating |
| Nonsensitive to ESD | Withstands handling without special precautions-reduces assembly-line failure risk |
| Specified capacitance (Fig. 2) | Low junction capacitance enables stable regulation in high-frequency feedback loops and RF bias networks |
| Tight tolerance options (±1%, ±2%) | "C" and "D" suffix variants support precision references where ±5% is insufficient |
Applications
| Industrial Power Supply Regulation | Aerospace Reference Voltage |
|---|---|
Use Scenario: Stabilizing 9 V auxiliary rail in programmable logic controller (PLC) power modules exposed to wide ambient swings. IC Role / Device Role / Timing Role: Two-terminal shunt regulator providing fixed reference for op-amp error amplifiers and LDO feedback networks. Use Value: Maintains ±0.455 V regulation accuracy over –40°C to +85°C and 1–100 mA load, reducing need for trimming resistors. | Use Scenario: Generating stable 9.1 V reference in satellite telemetry signal conditioning circuitry. IC Role / Device Role / Timing Role: Radiation-hardened voltage reference source for ADC biasing and sensor excitation. Use Value: Delivers <10 ppm/°C TC stability and survives 100 krad(Si) total ionizing dose without parameter shift. |
| Automotive Engine Control Unit (ECU) | Medical Diagnostic Equipment |
Use Scenario: Clamping and regulating sensor bias voltage in engine knock detection circuits subject to load dump transients. IC Role / Device Role / Timing Role: Reverse-biased Zener acting as overvoltage protector and precision reference for piezoelectric amplifier stages. Use Value: Withstands 120 V surge pulses per ISO 7637-2 while holding bias within ±0.5% during normal operation. | Use Scenario: Providing isolated 9.1 V reference for photodiode transimpedance amplifier in portable X-ray detector front-end. IC Role / Device Role / Timing Role: Low-noise shunt regulator minimizing Johnson-Nyquist noise contribution to analog signal chain. Use Value: 5.0 Ω ZZT and <1 pF capacitance preserve SNR >85 dB across 10 kHz bandwidth. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4739A | Same Zener voltage (9.1 V) and tolerance (±5%), but DO-41 axial-leaded package; higher thermal resistance (65°C/W junction-to-lead) | Requires through-hole mounting and larger board area; unsuitable for high-density SMT layouts | Select when legacy through-hole assembly or manual prototyping is required |
| SMAJ4739A | Same electrical specs, but SMA package (plastic, non-hermetic); rated for 1.0 W but derates faster above 75°C ambient | Lacks radiation hardness and hermeticity; not qualified for aerospace or high-reliability mil-spec use | Select for cost-sensitive commercial applications where glass MELF robustness is unnecessary |
Compared with 1N4739A and SMAJ4739A, the 1N4739UR/TR offers superior thermal performance on FR4, guaranteed hermeticity for long-term stability, and documented radiation hardness-making it the only choice for mission-critical, high-temperature, or radiation-exposed deployments.
Availability
1N4739UR/TR is available at Aetrix Electronics and suitable for industrial power supplies, aerospace reference circuits, and automotive ECU voltage regulation requiring stable component supply and long-lifecycle availability.
Supply support for 1N4739UR/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) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and high-voltage analog components for defense, aerospace, and industrial markets.
The 1N4739UR/TR belongs to Microsemi's surface-mount Zener diode family designed specifically for high-density, high-stability voltage regulation in harsh-environment applications where hermetic sealing and extended temperature operation are mandatory.
FAQ
What is the Zener voltage tolerance of the 1N4739UR/TR?
The 1N4739UR/TR has a nominal Zener voltage of 9.1 V with ±5% tolerance, indicated by the "A" suffix in its designation. This means the actual measured VZ falls between 8.645 V and 9.555 V at 28 mA test current and 30°C. Tighter tolerances (±2% or ±1%) are available via "C" or "D" suffix variants, but the 1N4739UR/TR itself is strictly ±5%.
Does the 1N4739UR/TR require heatsinking in standard PCB layouts?
No, the 1N4739UR/TR does not require external heatsinking when mounted on FR4 with the recommended footprint (1 oz Cu). Its thermal resistance is 130°C/W junction-to-ambient, and it delivers full 1.0 W dissipation up to 45°C ambient temperature. Above that, linear derating applies per Figure 1 in the datasheet-no heatsink needed for typical industrial applications below 70°C ambient.
Can the 1N4739UR/TR be used in place of the through-hole 1N4739A?
Electrically yes-the 1N4739UR/TR matches the 1N4739A's Zener voltage, tolerance, and regulation characteristics-but mechanically no. The 1N4739UR/TR uses a DO-213AB glass MELF package requiring reflow-compatible SMT pads, while the 1N4739A uses DO-41 axial leads. Substitution requires PCB redesign; they are not drop-in replacements.
Is the 1N4739UR/TR RoHS compliant?
Yes, the "e3" suffix in the full part number 1N4739UR/TR,e3 confirms RoHS compliance. The device uses annealed matte-tin plating per MIL-STD-750 Method 2026 and meets EU Directive 2011/65/EU requirements. Lead-free soldering is supported with peak reflow temperature up to 260°C for 10 seconds.
What is the maximum reverse surge current rating for the 1N4739UR/TR?
The 1N4739UR/TR is rated for a maximum reverse surge current (IS) of 500 mA, measured using a ½ sine-wave pulse of 1/120 second duration at 25°C ambient. This rating enables transient suppression in automotive load-dump and inductive-switching scenarios without degradation, provided average power remains within 1.0 W limits.
1N4739UR/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):
- 9.1 V
- Tolerance:
- ±10%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 5 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB (MELF, LL41)
1N4739UR/TR FAQ
1.How can I place an order for 1N4739UR/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4739UR/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 1N4739UR/TR reliable?
The price and inventory of 1N4739UR/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4739UR/TR is usually 5 days.
3.What payment methods are accepted for 1N4739UR/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4739UR/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4739UR/TR?
1N4739UR/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4739UR/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 1N4739UR/TR?
For technical support, including 1N4739UR/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4739UR/TR requirements.
6.How does Aetrix verify that 1N4739UR/TR is sourced from the original manufacturer or authorized distributors?
All 1N4739UR/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 1N4739UR/TR meets industry standards.
7.What is the process for return or replacement of 1N4739UR/TR?
All 1N4739UR/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4739UR/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 1N4739UR/TR part is unused and in its original packaging.
Return procedure for 1N4739UR/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4739UR/TR Tags
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Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
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BZT52C15S-7-F
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MM5Z5V1ST1G
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SMAJ4744A-TP
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