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Microchip Technology 1N4987US/TR
- Part No.:
- 1N4987US/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- SQ-MELF, E
- Datasheet:
-
1N4987US/TR.pdf
- Description:
- DIODE ZENER 160V 5W E-MELF
- Quantity:
- Payment:
- Shipping:
Inventory:100
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Product details
Overview
1N4987US/TR from Microsemi is a surface-mount, voidless-hermetically-sealed glass Zener diode rated for 5 W power dissipation at TEC = 125 °C, with nominal Zener voltage of 160 V at 8 mA test current, ±5% tolerance, and dynamic impedance of 350 Ω at IZT. It serves as a precision voltage reference or overvoltage clamp in high-reliability power regulation circuits.
For engineers reviewing the 1N4987US/TR datasheet, 1N4987US/TR pinout, 1N4987US/TR application, or 1N4987US/TR equivalent, this part is selected for aerospace, defense, and industrial systems requiring MIL-PRF-19500/356 qualification, extended temperature operation (–65 °C to +175 °C), and radiation-hardened performance per MicroNote 050.
Technical Context
This device operates in reverse breakdown mode with a specified Zener voltage of 160 V at IZT = 8 mA and exhibits low dynamic impedance (350 Ω) to maintain stable regulation across load and line variations. Its thermal resistance is 10 °C/W junction-to-end-cap, supporting reliable 5 W operation when mounted on thermally optimized PCB pads.
The 1N4987US/TR uses triple-layer passivation and Category III internal metallurgical bonds per MIL-PRF-19500/356, ensuring robustness against moisture ingress, mechanical stress, and ESD (MIL-STD-750 Method 1020). It features a cathode band marking and Sn/Pb-finished copper end caps in an "E" (D-5B) hermetic glass package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 160 V at IZT = 8 mA - defines precise clamping/reference level in regulated power rails |
| Power Dissipation | 5 W @ TEC = 125 °C - enables stable operation without derating below 125 °C ambient |
| Dynamic Impedance ZZT | 350 Ω @ IZT - ensures minimal output voltage variation under changing load current |
| Max Reverse Leakage IR | 2 μA @ VR = 121.6 V - guarantees low standby power loss in high-impedance bias networks |
| Temp Coefficient αVZ | +0.105 %/°C - quantifies predictable positive drift for temperature-compensated designs |
| Surge Current IZSM | 29.4 A @ 8.3 ms - supports transient overvoltage suppression in lightning/surge-prone environments |
| Operating Temperature | –65 °C to +175 °C - validated for extreme-environment deployment without derating |
Pinout & Package
Package: Hermetically sealed voidless hard glass case with tungsten slugs, "E" outline (also designated D-5B), cathode indicated by band, Sn/Pb-finished copper end caps, weight 539 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side connection | Connected to circuit ground or lower potential node during Zener operation |
| Cathode | Reverse-biased Zener terminal / high-side connection | Connected to unregulated input rail; voltage referenced to anode during regulation |
Key Features
| Feature | Design Value |
|---|---|
| Voidless hermetic glass construction | Eliminates internal delamination risk and ensures long-term parameter stability in humid or vacuum environments |
| Category III metallurgical bond | Meets MIL-PRF-19500/356 requirements for high-reliability military/aerospace applications |
| Triple-layer passivation | Provides enhanced surface insulation and protection against contamination-induced leakage |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Enables safe handling and assembly without special ESD controls beyond standard practices |
| Inherent radiation hardness | Validated per Microsemi MicroNote 050 for total ionizing dose (TID) resilience in space-grade systems |
Applications
| Aerospace Power Conditioning | Defense System Voltage Reference |
|---|---|
|
Use Scenario: Regulating auxiliary supply rails in satellite power distribution units exposed to thermal cycling and radiation. IC Role / Device Role / Timing Role: Zener diode acting as primary voltage reference for DC-DC converter feedback loops. Use Value: Maintains ±5% regulation accuracy over –65 °C to +175 °C and survives >100 krad(Si) TID per MicroNote 050. |
Use Scenario: Providing stable bias voltage for analog front-ends in radar receiver modules operating in harsh battlefield conditions. IC Role / Device Role / Timing Role: Precision shunt regulator establishing fixed reference for ADC drivers and op-amp offset calibration. Use Value: Delivers <2 μA leakage at 121.6 V, minimizing error contribution in high-impedance sensor signal chains. |
| Industrial High-Voltage Clamping | Military Communication Transceiver Protection |
|
Use Scenario: Overvoltage protection for 150 V DC bus lines in railway traction control inverters subject to switching transients. IC Role / Device Role / Timing Role: Shunt clamping element absorbing surge energy during IGBT turn-off events. Use Value: Withstands 29.4 A non-repetitive surge at 8.3 ms, limiting bus voltage to ≤160 V without degradation. |
Use Scenario: Input stage protection for HF/VHF transceivers deployed in mobile command vehicles exposed to EMP-like transients. IC Role / Device Role / Timing Role: Fast-acting Zener clamp placed before RF amplifier inputs to prevent gate oxide damage. Use Value: Responds within nanoseconds due to low capacitance (<2 pF typical) and maintains integrity after repeated 8.3 ms surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4987US | Same electrical specs and package; TR suffix indicates tape-and-reel packaging per EIA-481-B | No functional difference; identical use in automated SMT assembly | Select 1N4987US/TR for pick-and-place production; select 1N4987US for manual prototyping or low-volume hand-soldering |
| 1N4987 | Axial-leaded variant (no "US" suffix); same Zener voltage, 5 W rating, but TO-204AA metal-can package | Requires through-hole mounting; higher thermal resistance (≈15 °C/W) limits sustained power in compact layouts | Choose 1N4987 only when legacy board design mandates axial leads or when forced-air cooling is unavailable |
Compared with 1N4987US/TR, the bare 1N4987US offers identical performance in SMT form, while the axial 1N4987 trades mountability and thermal efficiency for compatibility with older PCB footprints - neither is pin-compatible due to differing package geometries.
Availability
1N4987US/TR is available at Aetrix Electronics and suitable for aerospace power conditioning, defense system voltage reference, and industrial high-voltage clamping requiring stable component supply across extended product lifecycles.
Supply support for 1N4987US/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 manufacturer specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.
The 1N49xxUS series belongs to Microsemi's military-qualified Zener diode product line, engineered specifically for applications demanding MIL-PRF-19500/356 compliance, hermetic reliability, and radiation tolerance.
FAQ
What is the Zener voltage tolerance for 1N4987US/TR?
The 1N4987US/TR has a nominal Zener voltage of 160 V with a standard tolerance of ±5%, as specified in the Microsemi SD44A datasheet. No suffix letter (e.g., "C" or "D") appears in the part number, confirming the 5% tolerance grade. This tolerance applies across the full operating temperature range of –65 °C to +175 °C.
Does 1N4987US/TR require heatsinking in 5 W operation?
Yes - the 1N4987US/TR achieves its full 5 W rating only when the end cap temperature (TEC) is maintained at ≤125 °C. With a thermal resistance of 10 °C/W junction-to-end-cap, a 50 °C temperature rise above ambient requires effective PCB copper pour or external heatsinking. Operation above 125 °C triggers linear derating to zero at 175 °C.
Is 1N4987US/TR compliant with RoHS or lead-free requirements?
No - the 1N4987US/TR uses Sn/Pb (tin/lead) finish on its copper end caps, as explicitly stated in the SD44A datasheet. It is not RoHS-compliant and is intended for high-reliability applications where Pb-based soldering remains permitted under exemptions such as EU Directive 2011/65/EU Annex III.
What is the maximum reverse leakage current for 1N4987US/TR?
The maximum reverse leakage current (IR) for 1N4987US/TR is 2 μA at VR = 121.6 V and TA = 25 °C, per the Electrical Characteristics table in SD44A. This value remains valid up to +175 °C, with leakage increasing predictably per device physics but staying within MIL-PRF-19500/356 limits.
Can 1N4987US/TR be used in place of 1N4987?
No - although electrically identical, 1N4987US/TR and 1N4987 differ in package: the former is surface-mount "E" (D-5B) glass, the latter is axial-leaded TO-204AA metal-can. They are not mechanically interchangeable. PCB layout, thermal management, and assembly process must match the specific package - no direct substitution is possible without redesign.
1N4987US/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):
- 160 V
- Tolerance:
- ±5%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 350 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 121.6 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
1N4987US/TR FAQ
1.How can I place an order for 1N4987US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4987US/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 1N4987US/TR reliable?
The price and inventory of 1N4987US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4987US/TR is usually 5 days.
3.What payment methods are accepted for 1N4987US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4987US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4987US/TR?
1N4987US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4987US/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 1N4987US/TR?
For technical support, including 1N4987US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4987US/TR requirements.
6.How does Aetrix verify that 1N4987US/TR is sourced from the original manufacturer or authorized distributors?
All 1N4987US/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 1N4987US/TR meets industry standards.
7.What is the process for return or replacement of 1N4987US/TR?
All 1N4987US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4987US/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 1N4987US/TR part is unused and in its original packaging.
Return procedure for 1N4987US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4987US/TR Tags
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