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Microchip Technology 1N4121UR/TR
- Part No.:
- 1N4121UR/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AA
- Datasheet:
-
1N4121UR/TR.pdf
- Description:
- DIODE ZENER 33V 500MW DO213AA
- Quantity:
- Payment:
- Shipping:
Inventory:8,134
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Product details
Overview
1N4121UR/TR from Microsemi is a glass-encapsulated surface-mount Zener diode in DO-213AA (SOD-80/MELF) package, rated for 0.5 W steady-state power dissipation, with nominal Zener voltage 33 V ±5%, Zener test current 250 mA, and maximum Zener impedance 200 Ω at IZT. It regulates voltage in precision reference and overvoltage protection circuits across industrial temperature range.
For engineers reviewing the 1N4121UR/TR datasheet, 1N4121UR/TR pinout, 1N4121UR/TR application, or 1N4121UR/TR equivalent, key selection criteria include its 33 V regulation tolerance, low noise density (1 µV/√Hz), hermetic glass package, -65°C to +175°C operating range, and RoHS-compliant e3 marking with TR tape-and-reel packaging.
Technical Context
This device operates as a reverse-biased voltage reference, maintaining stable 33 V output across load currents from 1 mA to 40 mA. Its Zener impedance of 200 Ω at 250 µA test current ensures minimal voltage deviation under dynamic load conditions.
Designed for high-reliability environments, it features inherent radiation hardness per MicroNote 050, ESD insensitivity per MIL-STD-750 Method 1020, and thermal resistance of 150°C/W junction-to-end-cap when mounted per recommended footprint on FR4.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 33 V ±5% - defines regulated output voltage under specified test conditions (IZT = 250 µA) |
| Steady-State Power Dissipation | 0.5 W at TEC < 100°C - limits continuous thermal stress on junction in standard mounting |
| Zener Impedance | 200 Ω max at IZT = 250 µA - determines output voltage stability against load current variation |
| Maximum Reverse Current | 0.01 µA at VR = 25.08 V - specifies leakage below regulation threshold, critical for low-power bias networks |
| Noise Density | 1 µV/√Hz typical at IZT - enables use in low-noise analog references and sensor excitation circuits |
| Operating Temperature Range | -65°C to +175°C - supports deployment in aerospace, downhole, and military systems without derating |
| Forward Voltage | 1.1 V @ 200 mA - defines conduction behavior during forward-bias fault conditions or polarity-check circuits |
Pinout & Package
DO-213AA (SOD-80/MELF) hermetically sealed glass package with axial symmetry and cathode band marking. No discrete pins - two end-cap terminals; cathode identified by single dark band, operated with banded end positive relative to opposite end for Zener regulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Regulated output node | Connected to higher-potential rail; voltage referenced to anode; polarity must be observed to enable Zener breakdown |
| Anode (unbanded end) | Reference/return node | Typically tied to system ground or lower-potential rail; completes Zener conduction path during regulation |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass MELF construction | Eliminates moisture ingress and long-term parameter drift; enables 175°C operation without seal degradation |
| Low noise density (1 µV/√Hz) | Supports high-resolution ADC references and precision analog front-ends where supply ripple must be minimized |
| Radiation-hardened design | Validated per Microsemi MicroNote 050 for total ionizing dose (TID) resilience in space and nuclear environments |
| ESD immunity (MIL-STD-750 Method 1020) | Withstands handling and board assembly without protection circuitry, reducing BOM count in ruggedized designs |
| e3 RoHS-compliant plating | Tin-lead alternative replaced with annealed matte-tin finish, compliant with lead-free soldering profiles up to 260°C/10 s |
Applications
| Industrial Sensor Reference | Aerospace Power Monitoring |
|---|---|
Use Scenario: Providing stable excitation voltage to strain gauge bridges in factory-floor pressure transmitters. IC Role / Device Role / Timing Role: Zener diode acting as two-terminal shunt voltage reference. Use Value: 33 V regulation with ±5% tolerance and 200 Ω impedance maintains bridge linearity across -40°C to +85°C ambient. | Use Scenario: Monitoring bus voltage in satellite power distribution units using discrete comparator-based overvoltage detection. IC Role / Device Role / Timing Role: Precision voltage clamp defining trip threshold for fault logic. Use Value: Radiation-hardened 33 V reference ensures reliable trip point stability after 100 krad(Si) TID exposure. |
| Downhole Oilfield Instrumentation | Military Radio Bias Supply |
Use Scenario: Generating local 33 V bias for RF amplifier stages in high-temperature logging tools deployed at 175°C wellbore depths. IC Role / Device Role / Timing Role: High-temperature-stable shunt regulator replacing active solutions. Use Value: Full -65°C to +175°C operational range eliminates need for thermal derating or external heatsinking. | Use Scenario: Establishing reference voltage for analog-to-digital conversion of battery voltage in handheld tactical radios. IC Role / Device Role / Timing Role: Low-noise Zener reference feeding SAR ADC input stage. Use Value: 1 µV/√Hz noise density prevents quantization error increase in 12-bit measurement accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4745A | Plastic DO-41 package; 1 W rating; 33 V ±5%; ZZT = 35 Ω; max IR = 1 µA @ 25 V | Higher power capability but larger footprint and lower temperature rating (-65°C to +175°C vs. -65°C to +150°C) | Select for cost-sensitive, non-hermetic, higher-power applications where plastic package suffices |
| BZX55C33 | Plastic DO-35 package; 500 mW rating; 33 V ±5%; ZZT = 150 Ω; max IR = 0.1 µA @ 25 V | Lower leakage and impedance than 1N4121UR/TR but not radiation-hardened or MIL-STD-750 qualified | Select for commercial-grade consumer electronics requiring tighter impedance and lower leakage without hermeticity or radiation tolerance |
Compared with 1N4121UR/TR, 1N4745A offers higher power and lower impedance but lacks hermetic sealing and full military temperature range, while BZX55C33 provides better impedance and leakage specs in a lower-cost plastic package but omits radiation hardness and ESD immunity per MIL-STD-750.
Availability
1N4121UR/TR is available at Aetrix Electronics and suitable for industrial sensor reference, aerospace power monitoring, and downhole instrumentation requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for 1N4121UR/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 company specializing in high-reliability, radiation-hardened, and high-temperature analog and mixed-signal components.
The 1N4121UR/TR belongs to Microsemi's legacy DO-213AA glass Zener series, engineered for mission-critical applications demanding hermeticity, wide temperature operation, and intrinsic radiation tolerance.
FAQ
What is the Zener voltage tolerance for 1N4121UR/TR?
The 1N4121UR/TR has a nominal Zener voltage of 33 V with a standard tolerance of ±5%, as defined in the Microsemi datasheet for the 1N4099UR–1N4135UR series. This tolerance applies when no suffix (e.g., C or D) is present; the "TR" suffix denotes tape-and-reel packaging only and does not affect voltage tolerance. The 1N4121UR/TR is not rated for tighter tolerances unless explicitly ordered with C (±2%) or D (±1%) suffixes.
Is 1N4121UR/TR RoHS compliant?
Yes, the 1N4121UR/TR is RoHS compliant, indicated by the "e3" designation in its full part number (1N4121UR/TR-e3 per ordering conventions). It uses annealed matte-tin plating per MIL-STD-750 Method 2026 and is qualified for lead-free solder reflow up to 260°C for 10 seconds. Compliance is verified per Microsemi's published environmental specifications for the DO-213AA Zener family.
What is the maximum power dissipation for 1N4121UR/TR at 100°C end-cap temperature?
The 1N4121UR/TR is rated for 0.5 W steady-state power dissipation at end-cap temperature (TEC) < 100°C or ambient temperature (TA) < 25°C on FR4 with 1 oz copper. At exactly TEC = 100°C, power must be derated per Figure 2 in the datasheet; the linear derating slope yields approximately 0.35 W maximum allowable dissipation at TEC = 100°C.
Does 1N4121UR/TR have a defined pinout diagram or terminal assignment?
No, the 1N4121UR/TR has no pinout in the IC sense-it is a two-terminal axial device in DO-213AA (SOD-80/MELF) glass package. Terminals are end caps: the banded end is the cathode (Zener output), and the unbanded end is the anode (reference return). Polarity must be observed-cathode must be at higher potential than anode for regulation. No internal leads or bond wires are accessible.
What is the typical noise density of 1N4121UR/TR and how is it measured?
The typical noise density of 1N4121UR/TR is 1 µV/√Hz, measured using a 1 kHz to 3 kHz bandpass filter at 25°C ambient with constant Zener test current (IZT = 250 µA), per Microsemi MicroNote 202 methodology. This value reflects broadband RMS noise normalized to bandwidth and is confirmed in the Electrical Characteristics table on page 2 of the official datasheet.
1N4121UR/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AA
- Packaging:
- Tape & Reel (TR)
- 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 @ 25.08 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AA
1N4121UR/TR FAQ
1.How can I place an order for 1N4121UR/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4121UR/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 1N4121UR/TR reliable?
The price and inventory of 1N4121UR/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4121UR/TR is usually 5 days.
3.What payment methods are accepted for 1N4121UR/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4121UR/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4121UR/TR?
1N4121UR/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4121UR/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 1N4121UR/TR?
For technical support, including 1N4121UR/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4121UR/TR requirements.
6.How does Aetrix verify that 1N4121UR/TR is sourced from the original manufacturer or authorized distributors?
All 1N4121UR/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 1N4121UR/TR meets industry standards.
7.What is the process for return or replacement of 1N4121UR/TR?
All 1N4121UR/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4121UR/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 1N4121UR/TR part is unused and in its original packaging.
Return procedure for 1N4121UR/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4121UR/TR Tags
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