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Microchip Technology 1N987B
- Part No.:
- 1N987B
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AA, DO-7, Axial
- Datasheet:
-
1N987B.pdf
- Description:
- DIODE ZENER 120V 500MW DO7
- Quantity:
- Payment:
- Shipping:
Inventory:4,586
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Product details
Overview
1N987B from Microsemi is a silicon 500 mW axial-leaded Zener diode in DO-35 (DO-204AH) package, rated for 120 V nominal Zener voltage with ±5% tolerance, 1.0 mA Zener test current, 900 Ω dynamic impedance at IZT, and +0.11 %/°C temperature coefficient. It regulates voltage in precision reference and overvoltage protection circuits across industrial power supplies and instrumentation.
For engineers reviewing the 1N987B datasheet, 1N987B pinout, 1N987B application, or 1N987B equivalent, key selection factors include its 120 V regulation point, low 1.0 mA test current enabling low-power biasing, DO-35 glass-body thermal performance up to +175°C, and JEDEC-registered compliance for legacy design continuity.
Technical Context
The 1N987B operates as a reverse-biased voltage reference diode with sharp breakdown knee verified per Microsemi MicroNote 202. Its Zener impedance of 900 Ω at 1.0 mA ensures stable regulation under light-load conditions, while the +0.11 %/°C temperature coefficient supports predictable drift compensation in mid-to-high-voltage references.
Designed for axial-leaded through-hole mounting, it delivers 400 mW maximum steady-state dissipation at 3/8″ lead length (TL < 50°C), derating linearly to zero at +175°C. Reverse leakage remains ≤5 μA at 91.2 V (76% of VZ), confirming tight leakage control for high-impedance sensing nodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 120 V ±5% - defines precise regulation threshold for overvoltage clamping and reference generation |
| Zener Test Current | 1.0 mA - enables low-quiescent-current biasing in battery-powered or standby circuits |
| Zener Impedance | 900 Ω @ 1.0 mA - ensures minimal output voltage shift under varying load currents |
| Max DC Zener Current | 3.1 mA - sets absolute upper limit for continuous regulation without exceeding 400 mW dissipation |
| Temp Coefficient | +0.11 %/°C - quantifies voltage drift per degree Celsius for thermal error budgeting |
| Reverse Leakage | ≤5 μA @ 91.2 V - guarantees negligible current draw below regulation threshold |
| Operating Temp Range | −65°C to +175°C - supports deployment in aerospace, downhole, and military-grade environments |
Pinout & Package
Package: DO-35 (DO-204AH), hermetically sealed axial-leaded glass body with tin-lead or RoHS-compliant matte-tin plating; cathode indicated by band; polarity requires banded end to be positive during Zener operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded lead | Connected to circuit ground or lower-potential node during Zener regulation |
| Cathode | Banded lead | Connected to regulated voltage node; must be held at higher potential than anode |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N987B type | Ensures cross-manufacturer compatibility and long-term supply chain stability for legacy designs |
| Internal metallurgical bond option (-1 suffix) | Improves mechanical robustness and thermal cycling reliability for harsh-environment applications |
| RoHS-compliant variant (e3 suffix) | Meets EU environmental directives without performance trade-offs in voltage regulation accuracy |
| Nonsensitive to ESD per MIL-STD-750 Method 1020 | Eliminates need for external ESD protection in handling and assembly for production lines |
| Inherently radiation-hardened | Validated per Microsemi MicroNote 050 for use in space-qualified and nuclear instrumentation systems |
Applications
| Industrial Power Supply Reference | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Stable 120 V reference for feedback loop in isolated AC/DC converters operating from 200–400 VDC bus. IC Role / Device Role / Timing Role: Zener diode providing precision voltage reference for TL431 or optocoupler biasing. Use Value: ±5% tolerance and +0.11 %/°C TC enable <±2% total reference error over −40°C to +85°C ambient. |
Use Scenario: Transient suppression on 100 V DC rail in motor drive gate driver stage. IC Role / Device Role / Timing Role: Shunt clamp limiting voltage spikes to ≤120 V during IGBT switching events. Use Value: 3.1 mA max DC current rating allows reliable clamping without thermal runaway under sustained overvoltage. |
| High-Temperature Sensor Interface | Aerospace Voltage Monitor |
Use Scenario: Biasing thermistor network in downhole oilfield sensor operating at +150°C. IC Role / Device Role / Timing Role: Zener reference stabilizing ADC input range against supply variation. Use Value: Full −65°C to +175°C operating range and radiation hardness ensure functional integrity in extreme thermal cycles. |
Use Scenario: Redundant voltage monitor in satellite power distribution unit monitoring 110–130 V bus. IC Role / Device Role / Timing Role: Primary Zener reference for comparator-based undervoltage/overvoltage detection. Use Value: JEDEC registration and MIL-STD-750 ESD immunity support qualification for flight-critical subsystems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4742A (ON Semiconductor) | 12 V Zener voltage, 1 W power rating, DO-41 package, ±5% tolerance | Lower voltage, higher power - suitable for general-purpose 12 V regulation, not direct replacement for 120 V requirement | Select only when system requires 12 V reference and higher power margin; incompatible for 120 V use cases |
| BZX55C120 (Vishay) | 120 V Zener voltage, ±5% tolerance, 500 mW, DO-35 package, but 10 mA IZT and 1000 Ω ZZT | Higher test current increases quiescent power; higher impedance reduces regulation stability at light loads | Acceptable where 10 mA bias current is available and ±0.5% regulation stability is not critical |
Compared with 1N987B, the 1N4742A serves entirely different voltage classes and cannot substitute; the BZX55C120 matches voltage and package but demands higher bias current and offers poorer low-load regulation due to higher ZZT, making 1N987B preferable for low-power, high-stability 120 V references.
Availability
1N987B is available at Aetrix Electronics and suitable for industrial power supplies, aerospace voltage monitors, high-temperature sensor interfaces, and overvoltage protection clamps requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1N987B 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, RF, and radiation-hardened components for defense, aerospace, and industrial markets.
The 1N987B belongs to Microsemi's legacy JEDEC-registered 1N957B–1N992B Zener series, engineered for precision voltage regulation in mission-critical systems where thermal stability, ESD immunity, and long-term parametric consistency are mandatory.
FAQ
What is the Zener voltage tolerance for 1N987B?
The 1N987B has a nominal Zener voltage of 120 V with a ±5% tolerance, as indicated by the "B" suffix per JEDEC standard. This means the actual measured Zener voltage at 1.0 mA test current falls between 114 V and 126 V at 25°C, confirmed in Microsemi's REV C datasheet electrical characteristics table.
Can 1N987B be used in surface-mount designs?
No - the 1N987B is packaged exclusively in the axial-leaded DO-35 (DO-204AH) glass body. For surface-mount equivalents, Microsemi offers the MLL987B in DO-213AA (MELF) package; however, 1N987B itself requires through-hole PCB mounting with 3/8″ lead length for thermal derating compliance.
What is the maximum power dissipation for 1N987B at room temperature?
The 1N987B is rated for 500 mW maximum steady-state power at lead temperature <50°C, but its usable dissipation is limited to 400 mW at 3/8″ lead length per the datasheet's IZM calculation. At 25°C ambient on FR4 board, this drops to 480 mW - however, derating begins immediately above 50°C lead temperature, reaching zero at +175°C.
Does 1N987B require external ESD protection during handling?
No - the 1N987B is nonsensitive to ESD per MIL-STD-750 Method 1020, as stated in the official Microsemi datasheet. Its construction and process eliminate the need for additional ESD safeguards during PCB assembly or manual handling, reducing BOM count and process complexity.
How does the temperature coefficient of 1N987B affect its regulation accuracy?
The 1N987B has a +0.11 %/°C temperature coefficient, meaning its Zener voltage increases by approximately 0.132 V per 1°C rise above 25°C. Over a −40°C to +85°C junction range, this contributes up to ±14.5 V drift - so system-level compensation or tight ambient control is required for sub-1% total regulation accuracy.
1N987B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AA, DO-7, Axial
- Packaging:
- Bulk
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 120 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 900 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 91.2 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-7
1N987B FAQ
1.How can I place an order for 1N987B through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N987B 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 1N987B reliable?
The price and inventory of 1N987B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N987B is usually 5 days.
3.What payment methods are accepted for 1N987B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N987B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N987B?
1N987B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N987B 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 1N987B?
For technical support, including 1N987B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N987B requirements.
6.How does Aetrix verify that 1N987B is sourced from the original manufacturer or authorized distributors?
All 1N987B 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 1N987B meets industry standards.
7.What is the process for return or replacement of 1N987B?
All 1N987B units undergo pre-shipment inspection (PSI). If there is an issue with 1N987B, 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 1N987B part is unused and in its original packaging.
Return procedure for 1N987B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N987B Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
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