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Microchip Technology CDLL4121
- Part No.:
- CDLL4121
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF
- Datasheet:
-
CDLL4121.pdf
- Description:
- DIODE ZENER 33V 500MW DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:8,971
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Product details
Overview
CDLL4121 from Microsemi is a hermetically sealed, surface-mount silicon Zener diode in DO-213AA (MELF/LL34) package, rated for 33 V nominal Zener voltage at 250 µA test current, 200 Ω maximum Zener impedance, and 12 mA maximum Zener current, used for precision voltage regulation in aerospace and industrial power supply reference circuits.
For engineers reviewing the CDLL4121 datasheet, CDLL4121 pinout, CDLL4121 application, or CDLL4121 equivalent, this page delivers verified electrical specs, thermal derating behavior, cathode-polarity marking, hermetic glass-case reliability data, and direct alternative options for high-stability Zener reference design.
Technical Context
The CDLL4121 operates as a two-terminal voltage reference with fixed 33 V breakdown, specified under thermal equilibrium at 25°C ambient and validated across -65°C to +175°C junction temperature range. Its metallurgically bonded construction ensures stable long-term Zener voltage drift under thermal cycling.
Designed for low-current regulation (250 µA test current), it exhibits 0.01 µA maximum reverse leakage at 25.08 V and supports DC power dissipation up to 500 mW at 125°C end-cap temperature, with linear 10 mW/°C derating above that point.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 33 V ±5% at 250 µA - defines stable reference point for feedback loops in regulated DC supplies |
| Zener Impedance (ZZT) | 200 Ω max at 250 µA - limits output voltage variation under load transients |
| Reverse Leakage (IR) | 0.01 µA max at 25.08 V - ensures minimal error current in high-impedance reference nodes |
| Max Zener Current (IZM) | 12 mA - sets upper limit for safe continuous conduction without thermal runaway |
| Junction Temp Range | -65°C to +175°C - enables operation in extended-environment avionics and downhole electronics |
| Power Dissipation | 500 mW @ TEC = +125°C - determines heatsinking requirements on PCB |
Pinout & Package
Package: DO-213AA (MELF/LL34), hermetically sealed glass case with tin/lead lead finish; axial symmetry requires orientation by cathode band marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration |
| Cathode | Zener breakdown terminal | Banded end; connected to higher-potential node to enable controlled avalanche conduction |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass sealing | Prevents moisture ingress and parametric shift in harsh environments (MIL-PRF-19500/435 qualified) |
| Metallurgical bonding | Ensures mechanical robustness and low thermal resistance (100 °C/W max junction-to-end-cap) |
| Low-current operation | Stable 33 V regulation at only 250 µA - ideal for battery-backed or ultra-low-power references |
| Wide temperature range | Validated operation from -65°C to +175°C - suitable for engine bay, space, or industrial control applications |
Applications
| Aerospace Power Reference | Industrial Sensor Excitation |
|---|---|
Use Scenario: Providing stable 33 V reference for ADC biasing and DAC calibration in satellite telemetry modules. IC Role / Device Role / Timing Role: Voltage reference element in analog front-end signal chain. Use Value: ±5% tolerance and <200 Ω impedance ensure sub-LSB error in 16-bit conversion systems over full temperature range. | Use Scenario: Supplying excitation voltage to strain-gauge bridges in factory-floor pressure transmitters. IC Role / Device Role / Timing Role: Precision shunt reference for ratiometric bridge biasing. Use Value: 0.01 µA leakage at 25.08 V prevents offset drift in high-impedance Wheatstone configurations. |
| Military Voltage Monitor | Downhole Tool Regulation |
Use Scenario: Monitoring 28 V bus integrity in vehicle-mounted C4I systems using comparator threshold referencing. IC Role / Device Role / Timing Role: Fixed-voltage threshold generator for undervoltage lockout detection. Use Value: Hermetic DO-213AA package withstands shock/vibration per MIL-STD-202, ensuring reliability during deployment. | Use Scenario: Regulating auxiliary supply rails in oil-well logging tools exposed to >150°C ambient. IC Role / Device Role / Timing Role: High-temperature shunt regulator for local LDO pre-regulation. Use Value: Validated operation to +175°C junction temperature enables direct mounting near heat sources without external cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C33 | 33 V ±5%, SOT-23 package, 350 mW PD, 600 Ω ZZT | Lower power rating and higher impedance reduce stability in precision analog circuits | Acceptable for cost-sensitive commercial designs where thermal margin and impedance tolerance are relaxed |
| 1N4745A | 33 V ±5%, DO-41 package, 1 W PD, 35 Ω ZZT, axial leads | Larger footprint and non-hermetic epoxy construction limit use in high-reliability or high-temp environments | Preferred when higher power handling is needed and board space allows axial through-hole mounting |
Compared with CDLL4121, BZX84-C33 offers smaller size but sacrifices impedance performance and hermetic reliability, while 1N4745A delivers lower impedance and higher power but lacks MIL-spec hermetic sealing and MELF thermal response - selection depends on priority between precision, ruggedness, and form factor.
Availability
CDLL4121 is available at Aetrix Electronics and suitable for aerospace power reference, industrial sensor excitation, military voltage monitor, and downhole tool regulation requiring stable component supply across extended temperature and reliability-critical programs.
Supply support for CDLL4121 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 CDLL series was developed specifically for MIL-PRF-19500/435-compliant Zener reference applications demanding hermetic sealing, wide temperature operation, and low-current stability - targeting mission-critical voltage regulation where parameter drift is unacceptable.
FAQ
What is the Zener voltage tolerance for CDLL4121?
The CDLL4121 has a nominal Zener voltage of 33 V with a tolerance of ±5%, measured at 250 µA test current and 25°C ambient temperature. This tolerance is defined per MIL-PRF-19500/435 and applies to the standard CDLL4121 variant; tighter tolerances (±2% or ±1%) require suffixes "C" or "D", which are not part of the base CDLL4121 designation.
Is CDLL4121 suitable for high-temperature operation?
Yes, CDLL4121 is rated for junction and storage temperatures from -65°C to +175°C and is validated for continuous operation in that range. Its hermetic DO-213AA glass package and metallurgical bonding enable reliable performance in downhole, engine-control, and avionics applications where ambient temperatures exceed 125°C.
What does the "CDLL" prefix indicate in CDLL4121?
The "CDLL" prefix identifies Microsemi's family of hermetically sealed, low-leakage, low-current Zener diodes in DO-213AA (MELF/LL34) packages. It distinguishes them from the 1N4xxxUR-1 series, which share identical electrical specs but differ in packaging format and qualification documentation - CDLL denotes commercial-grade hermetic MELF variants compliant with MIL-PRF-19500/435.
How is polarity marked on CDLL4121?
CDLL4121 uses a cathode band marking on the glass body to indicate polarity: the banded end is the cathode and must be connected to the higher-potential node when operated in reverse-bias Zener mode. This axial marking aligns with DO-213AA mechanical symmetry and is visible under standard optical inspection.
What is the thermal resistance of CDLL4121?
The CDLL4121 has a maximum junction-to-end-cap thermal resistance (RθJC) of 100 °C/W at zero lead length, and a maximum thermal impedance (ZθJX) of 35 °C/W. These values are measured per JEDEC standards and inform PCB layout decisions for thermal management in high-power-density applications.
CDLL4121 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AB, MELF
- 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:
- 50 nA @ 25.1 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-213AB
CDLL4121 FAQ
1.How can I place an order for CDLL4121 through Aetrix?
Please submit a Request for Quotation (RFQ) for CDLL4121 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 CDLL4121 reliable?
The price and inventory of CDLL4121 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CDLL4121 is usually 5 days.
3.What payment methods are accepted for CDLL4121?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CDLL4121 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CDLL4121?
CDLL4121 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CDLL4121 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 CDLL4121?
For technical support, including CDLL4121 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CDLL4121 requirements.
6.How does Aetrix verify that CDLL4121 is sourced from the original manufacturer or authorized distributors?
All CDLL4121 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 CDLL4121 meets industry standards.
7.What is the process for return or replacement of CDLL4121?
All CDLL4121 units undergo pre-shipment inspection (PSI). If there is an issue with CDLL4121, 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 CDLL4121 part is unused and in its original packaging.
Return procedure for CDLL4121:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CDLL4121 Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
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MMSZ5231B-7-F
Diodes Incorporated
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onsemi
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MM5Z5V1ST1G
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SMAJ4744A-TP
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