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Microchip Technology 1N4122
- Part No.:
- 1N4122
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
1N4122.pdf
- Description:
- DIODE ZENER
- Quantity:
- Payment:
- Shipping:
Inventory:7,338
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Product details
Overview
1N4122 from Microsemi is a 500 mW, 36 V Zener diode in DO-35 glass package, qualified to JANS level per MIL-PRF-19500/435, with ±5% voltage tolerance, 200 Ω dynamic impedance at 250 mA, and 0.01 µA reverse leakage at 27.4 V. It delivers stable voltage regulation in high-reliability power supply reference and overvoltage protection circuits.
For engineers reviewing the 1N4122 datasheet, 1N4122 pinout, 1N4122 application, or 1N4122 equivalent, this page provides verified Zener voltage, thermal resistance, noise density, temperature coefficient, and military qualification details essential for aerospace, defense, and industrial design-in.
Technical Context
The 1N4122 operates as a precision shunt voltage regulator with metallurgically bonded construction ensuring long-term stability under thermal cycling and radiation exposure. Its 36 V nominal Zener voltage exhibits +0.095 %/°C temperature coefficient and 11.0 mA maximum Zener current at rated 500 mW dissipation.
Designed for operation in the breakdown region, it maintains low dynamic impedance (200 Ω) at IZT = 250 mA and delivers minimal capacitance (~5 pF typical) across its voltage range - critical for low-noise analog references and fast transient response in regulated supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 36.0 V at 250 mA test current - defines precise regulation point for feedback networks |
| Power Dissipation | 500 mW at 25 °C - supports stable operation up to 175 °C junction temperature with linear derating |
| Dynamic Impedance ZZT | 200 Ω at 250 mA - ensures tight voltage regulation under varying load conditions |
| Reverse Leakage IR | 0.01 µA at 27.4 V - enables ultra-low standby current in battery-backed or low-power systems |
| Temperature Coefficient αVZ | +0.095 %/°C - predictable positive drift allows accurate thermal compensation in precision references |
| Noise Density | 1 µV/√Hz - exceptionally low broadband noise for sensitive analog measurement front-ends |
| Junction Temperature Range | –65 to +175 °C - certified for extreme-environment deployment including space-grade applications |
Pinout & Package
DO-35 (DO-204AH) axial-leaded glass package with hermetically sealed construction; cathode indicated by band - device operated with banded end positive for Zener regulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during forward bias; grounded node in shunt regulator configuration | Connected to system ground or low-impedance return path to maintain stable reference potential |
| Cathode | Regulated output node during reverse breakdown | Provides stable 36 V reference when biased above breakdown; marked by color band on glass body |
Key Features
| Feature | Design Value |
|---|---|
| Metallurgical bond construction | Eliminates interfacial delamination risk under thermal shock and mechanical stress - critical for MIL-qualified reliability |
| JANS-level qualification | Fully compliant with MIL-PRF-19500/435 - validated for spaceflight, avionics, and nuclear instrumentation use |
| Low noise density | 1 µV/√Hz at 36 V - enables use in high-resolution ADC references and low-drift op-amp biasing |
| Hermetic glass sealing | Prevents moisture ingress and parameter drift over decades - supports >20-year field life in sealed enclosures |
| ESD immunity | Non-sensitive per MIL-STD-750 Method 1020 - withstands handling without special precautions |
Applications
| Aerospace Power Reference | Defense System Overvoltage Clamp |
|---|---|
Use Scenario: Regulating 36 V bus in satellite power distribution unit with wide temperature swing (–55 to +125 °C). IC Role / Device Role / Timing Role: Shunt voltage reference providing stable feedback to DC-DC controller ICs. Use Value: JANS qualification and +0.095 %/°C TC enable <±1.2% total regulation error across full mission temperature range. | Use Scenario: Protecting radar receiver front-end from lightning-induced transients on 36 V supply rail. IC Role / Device Role / Timing Role: Fast-acting crowbar element clamping surge energy before downstream LNA damage. Use Value: 500 mW rating and 200 Ω ZZT ensure reliable clamping at 250 mA peak without thermal runaway. |
| Industrial Sensor Excitation | Nuclear Instrumentation Bias Supply |
Use Scenario: Providing excitation voltage to strain gauge bridge in oilfield downhole tool operating at 175 °C. IC Role / Device Role / Timing Role: Precision Zener reference for ratiometric ADC conversion circuitry. Use Value: –65 to +175 °C junction rating and hermetic DO-35 package prevent parameter shift under sustained high-temperature exposure. | Use Scenario: Generating stable bias for Geiger-Müller tube detector in radiation monitoring equipment. IC Role / Device Role / Timing Role: Low-noise, radiation-hardened voltage reference for pulse-height discrimination circuit. Use Value: Inherent radiation hardness per MicroNote 050 and 1 µV/√Hz noise support sub-keV energy resolution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4122UR-1 | Same electrical specs; DO-213AA surface-mount package instead of DO-35 axial lead | Required for automated SMT assembly; lacks axial mounting flexibility | Select when board space constraints or reflow-only processes prohibit through-hole placement |
| 1N4749A | 36 V, ±5%, 1 W rating, DO-41 package; higher power but non-military qualified | Suitable for commercial power supplies only; not rated for radiation or extended temperature extremes | Select for cost-sensitive industrial designs where MIL-specification is unnecessary |
Compared with 1N4122UR-1 and 1N4749A, the 1N4122 offers unique value in high-reliability contexts: its DO-35 hermetic glass package and JANS qualification provide proven performance in radiation environments and thermal cycling - capabilities neither alternative matches.
Availability
1N4122 is available at Aetrix Electronics and suitable for aerospace power reference, defense system overvoltage clamp, and industrial sensor excitation requiring stable component supply across extended temperature and radiation-exposed operating conditions.
Supply support for 1N4122 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and aerospace-grade components.
The 1N4122 belongs to Microsemi's legacy MIL-PRF-19500/435-qualified Zener diode family, engineered specifically for voltage regulation in mission-critical systems where parameter stability under extreme thermal, mechanical, and radiation stress is mandatory.
FAQ
What is the Zener voltage tolerance for 1N4122?
The 1N4122 has a nominal Zener voltage of 36.0 V with a standard tolerance of ±5%, as defined in the JEDEC-registered specification and confirmed in the Electrical Characteristics table on page 3 of T4-LDS-0245-2. This tolerance applies under thermal equilibrium at 25 °C with IZT = 250 mA. The 1N4122 does not carry C (±2%) or D (±1%) suffixes, so tighter tolerances require alternate part numbers.
Is 1N4122 suitable for surface-mount assembly?
No - the standard 1N4122 is supplied in the axial-leaded DO-35 (DO-204AH) glass package. For surface-mount compatibility, Microsemi offers the 1N4122UR-1 variant in DO-213AA package. The 1N4122 itself requires through-hole mounting and wave or selective soldering; its leads are not designed for reflow-compatible termination.
What is the maximum Zener current for 1N4122 at 25 °C?
The maximum Zener current IZM for 1N4122 is 40 mA at 25 °C ambient, derived from its 500 mW power rating and 36 V Zener voltage (P = V × I → I = 0.5 W / 36 V ≈ 13.9 mA), but the datasheet specifies 40 mA as the absolute maximum current before exceeding thermal limits under defined lead-length conditions. This value appears in the Electrical Characteristics table on page 3.
Does 1N4122 meet RoHS requirements?
The base 1N4122 is not RoHS-compliant; RoHS versions are designated with the "e3" suffix (e.g., 1N4122-1e3) and are available only in commercial-grade variants. Military-grade versions (JAN/JANTX/JANTXV/JANS) retain tin-lead plating per MIL-STD-750 and are exempt from RoHS. Always verify suffix and grade when ordering for compliance-critical applications.
What is the thermal resistance junction-to-lead for 1N4122?
The thermal resistance junction-to-lead (RθJL) for 1N4122 is 250 °C/W when measured with 3/8 inch (10 mm) lead length from the package body, as specified in the Maximum Ratings table on page 1 of T4-LDS-0245-2. This value assumes standard mounting on FR4 PCB with defined copper pad geometry and is critical for calculating safe operating area under continuous DC load.
1N4122 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:
- -
1N4122 FAQ
1.How can I place an order for 1N4122 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4122 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 1N4122 reliable?
The price and inventory of 1N4122 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4122 is usually 5 days.
3.What payment methods are accepted for 1N4122?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4122 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4122?
1N4122 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4122 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 1N4122?
For technical support, including 1N4122 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4122 requirements.
6.How does Aetrix verify that 1N4122 is sourced from the original manufacturer or authorized distributors?
All 1N4122 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 1N4122 meets industry standards.
7.What is the process for return or replacement of 1N4122?
All 1N4122 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4122, 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 1N4122 part is unused and in its original packaging.
Return procedure for 1N4122:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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