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Microchip Technology 1N4990US/TR
- Part No.:
- 1N4990US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4990US/TR.pdf
- Description:
- DIODE ZENER 220V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:41
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Product details
Overview
1N4990US/TR from Microsemi is a surface-mount, voidless hermetically sealed glass Zener diode rated for 5 W power dissipation at TEC = 140 °C, with nominal Zener voltage of 220 V ±5%, dynamic impedance of 550 Ω at IZT = 5 mA, and maximum reverse leakage current of 2 μA at VR = 167 V. It serves as a precision voltage reference or overvoltage clamp in high-reliability aerospace power conditioning circuits.
For engineers reviewing the 1N4990US/TR datasheet, 1N4990US/TR pinout, 1N4990US/TR application, or 1N4990US/TR equivalent, key selection criteria include its MIL-PRF-19500/356 qualification, -65 °C to +175 °C operating temperature range, hermetic glass package with tungsten slugs, and compatibility with EIA-481-B tape-and-reel handling.
Technical Context
This device operates in reverse breakdown mode with tightly controlled Zener voltage regulation across wide current (10%–50% of IZM) and temperature ranges. Its Category I metallurgical bond ensures mechanical integrity under thermal cycling and shock per MIL-STD-883.
The 1N4990US/TR exhibits low temperature coefficient (αVZ = +0.115 %/°C), minimal voltage drift (ΔVZ ≤ 19 V), and robust surge capability (IZSM = 1.8 A @ 8.3 ms). Its forward voltage is specified at 1.50 V @ 1.0 A, confirming silicon P-N junction construction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 220 V ±5% at IZT = 5 mA - defines stable regulation point for high-voltage biasing |
| Power Dissipation | 5 W @ TEC = 140 °C - requires heatsinking via end-cap thermal path to PCB |
| Dynamic Impedance (ZZT) | 550 Ω @ IZT = 5 mA - limits regulation error under load transients |
| Reverse Leakage (IR) | 2 μA max at VR = 167 V - ensures low standby power loss in high-impedance circuits |
| Thermal Resistance (RθJC) | 7 °C/W junction-to-end-cap - enables thermal modeling for derating above 140 °C |
| Surge Current (IZSM) | 1.8 A @ 8.3 ms half-sine - withstands transient overvoltage events without degradation |
| Operating Temperature | -65 °C to +175 °C - supports operation in extreme environments including space-grade systems |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs; copper end caps with Sn/Pb finish; polarity indicated by cathode band; weight 539 mg; "E" package (also known as "D-5B").
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node during normal operation; carries full surge current in forward bias |
| Cathode | Zener breakdown terminal | Marked with band; connected to higher-potential node; establishes regulated output voltage referenced to anode |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass seal | Prevents moisture ingress and internal corrosion, enabling >20-year reliability in sealed enclosures |
| Category I metallurgical bond | Ensures mechanical stability under MIL-STD-810H vibration and thermal shock profiles |
| MIL-PRF-19500/356 qualification | Validates compliance with military screening including burn-in, temperature cycling, and life testing |
| Nonsensitive to ESD | Withstands ≥4 kV HBM per MIL-STD-750 Method 1020 without parameter shift |
| Radiation hardness | Inherently tolerant to total ionizing dose (TID) per MicroNote 050 - suitable for low-earth orbit missions |
Applications
| Aerospace Power Bus Protection | Satellite DC-DC Converter Reference |
|---|---|
Use Scenario: Clamping transient spikes on 200–280 V primary bus in LEO satellite power distribution units. IC Role / Device Role / Timing Role: Zener diode acting as shunt overvoltage protector, clamping surges above 220 V to prevent downstream converter damage. Use Value: 1.8 A surge rating and 7 °C/W thermal resistance allow reliable energy absorption without thermal runaway under repeated 8.3 ms transients. |
Use Scenario: Providing stable 220 V reference for isolated feedback loop in radiation-hardened flyback controller. IC Role / Device Role / Timing Role: Precision voltage reference element setting output regulation threshold in optocoupler-coupled feedback path. Use Value: ±5% tolerance and +0.115 %/°C TC ensure <±1.5% total error over -55 °C to +125 °C operational range. |
| High-Reliability Industrial HV Sensor Bias | Military Radar Pulse Generator Clamp |
Use Scenario: Biasing avalanche photodiode arrays in nuclear instrumentation requiring stable 220 V bias under thermal cycling. IC Role / Device Role / Timing Role: High-voltage bias regulator maintaining constant reverse bias across sensor junctions. Use Value: Hermetic glass package prevents parameter drift due to humidity-induced leakage, critical for long-term calibration stability. |
Use Scenario: Protecting pulse-forming network (PFN) switches from voltage reversal during high-power radar transmit cycles. IC Role / Device Role / Timing Role: Fast-acting clamp limiting negative swing to ≤220 V during switch turn-off recovery. Use Value: Low 2 μA leakage at 167 V minimizes standby power loss while preserving fast response to overvoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4990US | Same electrical specs and package; differs only in packaging format (bulk vs. tape-and-reel) | No functional difference; 1N4990US/TR is optimized for automated SMT placement | Select 1N4990US/TR when using pick-and-place equipment requiring EIA-481-B compliant reels |
| 1N4990 | Axial-leaded version (no "US" suffix); same Zener voltage and power rating but different thermal path and mounting method | Requires through-hole PCB layout and wave soldering; not suitable for surface-mount-only designs | Choose 1N4990 only if legacy through-hole assembly infrastructure is in place and board real estate permits axial leads |
Compared with 1N4990US and 1N4990, the 1N4990US/TR provides identical Zener performance in a tape-and-reel format certified for high-volume SMT production, eliminating manual handling while preserving MIL-qualified reliability and hermetic sealing.
Availability
1N4990US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, satellite DC-DC converter reference, and high-reliability industrial HV sensor bias requiring stable component supply across extended product lifecycles.
Supply support for 1N4990US/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 analog and mixed-signal components for defense, aerospace, and industrial markets.
The 1N4990US/TR belongs to Microsemi's legacy MIL-PRF-19500/356 qualified Zener series, designed specifically for voltage regulation in mission-critical systems where failure is not an option.
FAQ
What is the Zener voltage tolerance for 1N4990US/TR?
The 1N4990US/TR has a nominal Zener voltage of 220 V with a standard tolerance of ±5%, as defined in the Electrical Characteristics table at IZT = 5 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. This tolerance directly impacts regulation accuracy in precision reference applications.
Is 1N4990US/TR suitable for space applications?
Yes, the 1N4990US/TR is inherently radiation-hardened per Microsemi MicroNote 050 and qualified to MIL-PRF-19500/356, making it suitable for low-earth orbit missions. Its hermetic voidless glass package and Category I metallurgical bond provide immunity to total ionizing dose and mechanical stress, critical for satellite power subsystems using the 1N4990US/TR.
What is the maximum continuous Zener current for 1N4990US/TR?
The maximum continuous Zener current (IZM) for 1N4990US/TR is 1.8 A, calculated from its 5 W power rating and 220 V Zener voltage (IZM = PZ/VZ). This value assumes operation at TEC = 140 °C; derating is required linearly to zero at 175 °C. This current limit defines safe steady-state operation in the 1N4990US/TR.
Does 1N4990US/TR have ESD protection built-in?
The 1N4990US/TR is nonsensitive to electrostatic discharge per MIL-STD-750 Method 1020, withstanding ≥4 kV HBM without parameter shift. This intrinsic ESD robustness eliminates the need for external protection circuitry in handling and assembly, enhancing yield and reliability in production environments deploying the 1N4990US/TR.
What package type is used for 1N4990US/TR?
The 1N4990US/TR uses the "E" package (also designated "D-5B"), a surface-mount hermetically sealed voidless glass case with tungsten slugs and copper end caps finished with Sn/Pb. Its polarity is marked by a cathode band, and it complies with EIA-481-B tape-and-reel standards for automated placement-key for consistent manufacturing of the 1N4990US/TR.
1N4990US/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):
- 220 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 550 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 167 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
1N4990US/TR FAQ
1.How can I place an order for 1N4990US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4990US/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 1N4990US/TR reliable?
The price and inventory of 1N4990US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4990US/TR is usually 5 days.
3.What payment methods are accepted for 1N4990US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4990US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4990US/TR?
1N4990US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4990US/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 1N4990US/TR?
For technical support, including 1N4990US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4990US/TR requirements.
6.How does Aetrix verify that 1N4990US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4990US/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 1N4990US/TR meets industry standards.
7.What is the process for return or replacement of 1N4990US/TR?
All 1N4990US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4990US/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 1N4990US/TR part is unused and in its original packaging.
Return procedure for 1N4990US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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