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Microchip Technology 1N4121-1
- Part No.:
- 1N4121-1
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N4121-1.pdf
- Description:
- DIODE ZENER 33V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:9,904
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Product details
Overview
1N4121-1 from Microsemi is a 500 mW, 33 V axial-leaded glass Zener diode in DO-35 (DO-204AH) package, qualified to JANTXV level per MIL-PRF-19500/435, with ±5% voltage tolerance, 200 Ω dynamic impedance at 250 mA test current, and 0.01 µA maximum reverse leakage at 25.1 V. It regulates voltage in precision reference and power supply feedback circuits across military avionics and industrial control systems.
For engineers reviewing the 1N4121-1 datasheet, 1N4121-1 pinout, 1N4121-1 application, or 1N4121-1 equivalent, key selection criteria include its JANTXV qualification, low noise density (≤1 µV/√Hz below 6.8 V), thermal resistance of 250 °C/W (junction-to-lead), and stable temperature coefficient of +0.095 %/°C - critical for high-reliability analog voltage references.
Technical Context
The 1N4121-1 operates as a reverse-biased Zener regulator with metallurgically bonded junction, enabling stable breakdown at 33 V under 250 mA test current. Its DO-35 hermetic glass package ensures immunity to moisture and contaminants, supporting operation from –65 °C to +175 °C junction temperature.
It exhibits 200 Ω dynamic impedance (ZZT) at IZT = 250 mA and maintains ≤0.01 µA reverse leakage (IR) at VR = 25.1 V, confirming tight regulation in low-current biasing conditions. The +0.095 %/°C temperature coefficient ensures predictable drift over wide thermal ranges without external compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 33.0 V at 250 mA - defines precise regulation point for feedback loops and reference generation |
| Power Dissipation | 500 mW at 25 °C - supports continuous operation in compact through-hole designs with linear derating above 50 °C |
| Dynamic Impedance (ZZT) | 200 Ω at 250 mA - determines output voltage stability under load transients |
| Reverse Leakage (IR) | ≤0.01 µA at 25.1 V - ensures minimal error current in high-impedance reference nodes |
| Temp. Coefficient (αVZ) | +0.095 %/°C - enables predictable, monotonic drift for calibrated systems |
| Noise Density (ND) | ≤1 µV/√Hz - critical for low-noise analog references and sensor excitation |
| Junction Temp. Range | –65 °C to +175 °C - validated for aerospace, downhole, and extended-temperature industrial use |
Pinout & Package
DO-35 (DO-204AH) axial-leaded glass package with cathode indicated by band; banded end is positive during Zener operation. Hermetically sealed, tin-lead or RoHS-compliant matte-tin plating, ~0.2 g mass.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node | Connected to system ground or low-side return; establishes reference potential for regulation |
| Cathode | Zener regulation output | Banded end; supplies stabilized 33 V when reverse-biased; must be held positive relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Metallurgical bond construction | Eliminates interfacial delamination risk under thermal cycling and mechanical shock |
| JANTXV qualification per MIL-PRF-19500/435 | Validated screening for burn-in, temperature cycling, and life testing in mission-critical hardware |
| Low noise density (≤1 µV/√Hz) | Enables use in precision analog front-ends without added filtering or post-regulation conditioning |
| Hermetic glass DO-35 package | Prevents humidity-induced parameter shift and long-term degradation in harsh environments |
| Non-ESD-sensitive per MIL-STD-750 Method 1020 | Allows handling without special ESD controls during manual assembly or rework |
Applications
| Avionics Reference Supply | Industrial PLC Analog Input |
|---|---|
Use Scenario: Providing stable 33 V reference for ADC biasing and DAC output scaling in flight control computers. IC Role / Device Role / Timing Role: Precision voltage reference source for signal conditioning circuitry. Use Value: JANTXV qualification and –65 °C to +175 °C operation ensure reliability across altitude and thermal extremes without recalibration. | Use Scenario: Regulating feedback voltage in isolated 24 V DC power supply for programmable logic controller I/O modules. IC Role / Device Role / Timing Role: Zener shunt regulator in secondary-side feedback loop of flyback converter. Use Value: 200 Ω dynamic impedance and 0.01 µA leakage maintain tight output regulation despite line/load variations and aging. |
| Military Radio Power Management | Test Equipment Calibration Reference |
Use Scenario: Stabilizing local oscillator bias in S-band tactical radios operating in desert and arctic environments. IC Role / Device Role / Timing Role: Temperature-stable voltage reference for VCO tuning and amplifier bias networks. Use Value: +0.095 %/°C coefficient and hermetic packaging prevent frequency drift and gain instability across –40 °C to +85 °C ambient. | Use Scenario: Serving as traceable 33 V calibration standard in benchtop multimeters and automated test systems. IC Role / Device Role / Timing Role: Primary voltage reference element in metrology-grade divider networks. Use Value: Low 1 µV/√Hz noise and <0.01 µA leakage minimize measurement uncertainty and enable sub-ppm accuracy verification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4121UR-1 | Same electrical specs, but in DO-213AA surface-mount package instead of DO-35 axial lead | Requires PCB redesign for SMT assembly; eliminates through-hole mounting and lead trimming | Select when space-constrained layouts or automated pick-and-place manufacturing is required |
| 1N4121-1e3 | Identical DO-35 package and electrical performance, but RoHS-compliant matte-tin plating (commercial grade only) | Not qualified to JANTXV; limited to commercial-temperature range (–65 °C to +150 °C) and non-military programs | Select for cost-sensitive industrial or telecom applications where mil-spec is not mandated |
Compared with 1N4121UR-1 and 1N4121-1e3, the 1N4121-1 uniquely delivers JANTXV-level reliability in the legacy DO-35 through-hole format - essential for repair, legacy system support, and programs requiring full MIL-PRF-19500 conformance.
Availability
1N4121-1 is available at Aetrix Electronics and suitable for avionics power supplies, industrial PLCs, military radio subsystems, and test equipment calibration requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1N4121-1 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 analog, RF, and radiation-hardened components for defense, aerospace, and industrial markets.
The 1N4121-1 belongs to Microsemi's legacy MIL-qualified Zener diode family, designed specifically for precision voltage regulation in mission-critical systems where parametric stability, environmental ruggedness, and long-term reliability are non-negotiable.
FAQ
What is the Zener voltage tolerance of the 1N4121-1?
The 1N4121-1 has a nominal Zener voltage of 33.0 V with a standard tolerance of ±5%, as defined by JEDEC registration and confirmed in the Electrical Characteristics table on page 3 of T4-LDS-0245-2 Rev. 1. This tolerance applies under thermal equilibrium at 25 °C with 250 mA test current. No tighter tolerance (e.g., 2% or 1%) is specified for this specific part number.
Is the 1N4121-1 suitable for surface-mount assembly?
No - the 1N4121-1 uses the axial-leaded DO-35 (DO-204AH) glass package and is intended for through-hole mounting. For surface-mount equivalents, Microsemi offers the 1N4121UR-1 in DO-213AA package. Substituting 1N4121-1 into an SMT footprint would require mechanical adaptation and is not recommended due to thermal and mechanical mismatch.
What is the maximum reverse leakage current for the 1N4121-1?
The 1N4121-1 has a maximum reverse leakage current (IR) of 0.01 µA at a reverse voltage (VR) of 25.1 V, as specified in the Electrical Characteristics table. This ultra-low leakage supports high-impedance reference nodes and minimizes error in precision analog circuits where bias current must be tightly controlled.
Does the 1N4121-1 meet RoHS requirements?
The base 1N4121-1 is not RoHS compliant; it uses traditional tin-lead plating. RoHS-compliant versions are designated with the "e3" suffix (e.g., 1N4121-1e3), but those are commercial-grade only and lack JANTXV qualification. The 1N4121-1 retains tin-lead finish to satisfy MIL-PRF-19500 solderability and reliability requirements for high-reliability programs.
What is the thermal resistance specification for the 1N4121-1?
The 1N4121-1 has a junction-to-lead thermal resistance (RθJL) of 250 °C/W when mounted with 3/8 inch (10 mm) lead length from body, per Maximum Ratings table. Its junction-to-ambient resistance (RθJA) is 300 °C/W under defined FR4 board conditions. These values govern safe power derating and thermal design in enclosed or high-temperature environments.
1N4121-1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 200 Ohms
- Current - Reverse Leakage @ Vr:
- 10 nA @ 25.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AH (DO-35)
1N4121-1 FAQ
1.How can I place an order for 1N4121-1 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4121-1 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 1N4121-1 reliable?
The price and inventory of 1N4121-1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4121-1 is usually 5 days.
3.What payment methods are accepted for 1N4121-1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4121-1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4121-1?
1N4121-1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4121-1 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 1N4121-1?
For technical support, including 1N4121-1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4121-1 requirements.
6.How does Aetrix verify that 1N4121-1 is sourced from the original manufacturer or authorized distributors?
All 1N4121-1 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 1N4121-1 meets industry standards.
7.What is the process for return or replacement of 1N4121-1?
All 1N4121-1 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4121-1, 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 1N4121-1 part is unused and in its original packaging.
Return procedure for 1N4121-1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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