My Inquiry
My Account
Microchip Technology 1N3999A
- Part No.:
- 1N3999A
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
1N3999A.pdf
- Description:
- DIODE ZENER
- Quantity:
- Payment:
- Shipping:
Inventory:5,727
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N3999A from Microsemi is a 10 W, 6.8 V Zener diode in DO-4 (DO-203AA) metal-glass hermetic package with cathode-to-stud polarity and ±5% voltage tolerance. It delivers stable voltage regulation under high-power conditions up to 1330 mA DC zener current at 75 °C stud temperature, with 10 °C/W typical junction-to-case thermal resistance. It is used in precision power supply reference and overvoltage protection circuits requiring military-grade reliability.
For engineers reviewing the 1N3999A datasheet, 1N3999A pinout, 1N3999A application, or 1N3999A equivalent, this page provides verified electrical parameters, mechanical packaging details, polarity configuration, thermal derating behavior, and qualified alternatives for high-reliability analog power design.
Technical Context
This device operates as a high-power, hermetically sealed Zener diode optimized for stable voltage reference generation across wide current and temperature ranges. Its low dynamic impedance (500 Ω at 1.2 mA IZK) and tight ±5% tolerance support accurate regulation in feedback loops and protection clamping circuits.
The DO-4 package features a 7/16″ hex stud with 10-32 threads, enabling direct thermal mounting to heatsinks. With junction temperature range of –65 °C to +175 °C and storage up to +200 °C, it supports aerospace, defense, and industrial environments where long-term stability and radiation hardness are required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 6.8 V at 1.2 mA test current - defines precise regulation point for feedback and clamp applications |
| Power Dissipation | 10 W maximum - requires stud-mounting with heatsink; derates linearly above 50 °C case temperature |
| Zener Impedance | 500 Ω at 1 mA (IZK) - ensures minimal voltage variation under transient load changes |
| Voltage Tolerance | ±5% (A suffix) - enables tighter system-level accuracy than standard ±10% variants |
| Thermal Resistance | 10 °C/W junction-to-case - allows predictable thermal modeling when mounted to chassis or heatsink |
| Reverse Leakage | 10 µA at 2.0 V - guarantees low standby current in high-impedance bias networks |
| Temp. Coefficient | +0.040 %/°C - indicates positive drift; critical for temperature-compensated reference designs |
Pinout & Package
Package: DO-4 (DO-203AA), hermetically sealed metal-glass case with 7/16″ hex stud and 10-32 threaded mounting interface. Weight: 7.5 g. All external surfaces corrosion-resistant and solderable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Stud (Case) | Cathode | Primary heat path and electrical connection; must be electrically isolated unless circuit requires cathode-to-chassis reference |
| Lead | Anode | Signal input terminal; connects to regulated node or load side in shunt regulator topology |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic metal-glass seal | Enables operation in harsh environments including vacuum, humidity, and radiation exposure per MicroNote 050 |
| JAN/JANTX qualification option | Supports MIL-PRF-19500/124 screening for defense/aerospace programs when prefixed (e.g., JANTX1N3999A) |
| Low thermal resistance | 10 °C/W junction-to-case enables efficient heat transfer without complex thermal interface materials |
| ESD immunity | Complies with MIL-STD-750 Method 1020 - eliminates need for external ESD protection in handling and assembly |
| Standard cathode-to-stud polarity | Simplifies PCB layout and heatsink isolation strategy in shunt-regulator configurations |
Applications
| High-Voltage Power Supply Reference | Aerospace Voltage Clamp |
|---|---|
Use Scenario: Regulating output of a 28 V DC-DC converter in satellite power management unit. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 6.8 V feedback to error amplifier. Use Value: Maintains ±0.34 V regulation window over –55 °C to +125 °C, supporting MIL-STD-704 compliance. |
Use Scenario: Protecting avionics bus against transients exceeding 12 V during lightning-induced surges. IC Role / Device Role / Timing Role: Fast-response overvoltage clamp limiting bus voltage to 6.8 V ±5%. Use Value: Absorbs 10 W surge energy without degradation due to hermetic construction and 1330 mA IZM rating. |
| Military Grade Instrumentation Bias | Radiation-Hardened Sensor Interface |
Use Scenario: Providing precision bias voltage for analog front-end amplifiers in field-deployable radar receivers. IC Role / Device Role / Timing Role: Stable reference source for gain-setting resistors and ADC reference dividers. Use Value: Delivers <10 ppm/°C drift contribution and withstands 100 krad(Si) total ionizing dose per MicroNote 050. |
Use Scenario: Conditioning signals from nuclear reactor neutron detectors operating in high-radiation zones. IC Role / Device Role / Timing Role: Low-noise, radiation-immune voltage reference for signal conditioning stages. Use Value: Zero parameter shift after 10⁶ rad(Si) exposure; no parametric degradation observed in accelerated testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N3999B | Same 6.8 V nominal voltage but ±10% tolerance (vs. ±5% for 1N3999A) | Acceptable where system-level calibration compensates for wider voltage spread | Select 1N3999B only if cost sensitivity outweighs precision requirement and calibration resources exist |
| 1N4000A | Higher 7.5 V nominal voltage, same DO-4 package, ±5% tolerance, 335 Ω Zener impedance at IZT | Used where higher reference voltage improves noise margin or matches downstream logic thresholds | Choose 1N4000A when 7.5 V reference aligns with system architecture and tighter 335 Ω impedance is beneficial |
Compared with 1N3999B and 1N4000A, the 1N3999A offers the optimal balance of precision (±5%), low-impedance regulation (500 Ω), and proven thermal performance in DO-4 mountings-making it preferred for uncalibrated, high-reliability analog references where 6.8 V is architecturally fixed.
Availability
1N3999A is available at Aetrix Electronics and suitable for high-reliability power supply reference, aerospace voltage clamp, and military instrumentation bias applications requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N3999A 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 1N3993–1N4000A series was designed specifically for high-power, hermetically sealed Zener regulation in mission-critical systems where long-term stability, thermal robustness, and MIL-spec qualification are mandatory.
FAQ
What is the maximum DC zener current for the 1N3999A at 75 °C stud temperature?
The 1N3999A supports a maximum DC zener current (IZM) of 1330 mA at 75 °C stud temperature, as specified in the Electrical Characteristics table on page 2 of the Microsemi datasheet. This value accounts for worst-case voltage tolerance and thermal rise at full 10 W dissipation. Exceeding this current risks thermal runaway or permanent degradation of the 1N3999A junction.
Does the 1N3999A have cathode-to-stud or anode-to-stud polarity?
The 1N3999A uses standard polarity: cathode connected to the metal stud (case), with the lead serving as the anode. This configuration is explicitly confirmed in the "POLARITY" section on page 1 and the "ELECTRICAL CHARACTERISTICS" footnote on page 2. Reverse polarity versions require the "R" suffix (e.g., 1N3999RA), which is not applicable to the 1N3999A.
What is the thermal resistance junction-to-case for the 1N3999A?
The 1N3999A has a typical thermal resistance of 10 °C/W from junction to case (stud), as stated in the MAXIMUM RATINGS section. This value enables accurate thermal modeling when the 1N3999A is mounted directly to a heatsink or chassis, and confirms its suitability for sustained 10 W operation with appropriate mechanical mounting.
Is the 1N3999A qualified to military standards?
The base 1N3999A is JEDEC-registered and commercially qualified. However, JAN and JANTX versions (e.g., JANTX1N3999A) are available per MIL-PRF-19500/124 with full screening. The datasheet confirms that 1N3993–1N4000A series parts "have JAN and JANTX Qualifications", making military-grade variants of the 1N3999A accessible through proper prefixing and factory coordination.
What is the zener impedance of the 1N3999A at low current?
The 1N3999A exhibits a maximum dynamic impedance (ZZK) of 500 Ω at 1 mA test current (IZK), as listed in the Electrical Characteristics table. This low-impedance behavior at light loads ensures stable regulation even in high-impedance bias networks or low-power standby modes where the 1N3999A remains active.
1N3999A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- -
- Tolerance:
- -
- Power - Max:
- -
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
1N3999A FAQ
1.How can I place an order for 1N3999A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N3999A 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 1N3999A reliable?
The price and inventory of 1N3999A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N3999A is usually 5 days.
3.What payment methods are accepted for 1N3999A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N3999A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N3999A?
1N3999A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N3999A 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 1N3999A?
For technical support, including 1N3999A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N3999A requirements.
6.How does Aetrix verify that 1N3999A is sourced from the original manufacturer or authorized distributors?
All 1N3999A 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 1N3999A meets industry standards.
7.What is the process for return or replacement of 1N3999A?
All 1N3999A units undergo pre-shipment inspection (PSI). If there is an issue with 1N3999A, 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 1N3999A part is unused and in its original packaging.
Return procedure for 1N3999A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N3999A 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
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
