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Microchip Technology CDLL821/TR
- Part No.:
- CDLL821/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AA
- Datasheet:
-
CDLL821/TR.pdf
- Description:
- DIODE ZENER 6.2V 500MW DO213AA
- Quantity:
- Payment:
- Shipping:
Inventory:2,954
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Product details
Overview
CDLL821/TR from Central Semiconductor (CDI) is a temperature-compensated, hermetically sealed glass MELF zener diode with nominal zener voltage 5.9–6.5 V, 7.5 mA test current, 15 Ω zener impedance, ±0.01 %/°C temperature coefficient, and 500 mW power dissipation at +50°C - used for precision voltage reference in analog power supply feedback loops.
For engineers reviewing the CDLL821/TR datasheet, CDLL821/TR pinout, CDLL821/TR application, or CDLL821/TR equivalent, key selection criteria include zener voltage tolerance, low tempco stability over –55°C to +100°C, low dynamic impedance at 7.5 mA, hermetic DO-213AA packaging for high-reliability environments, and compatibility with surface-mount reflow profiles.
Technical Context
The CDLL821/TR employs metallurgically bonded, double-plug construction to achieve tight voltage regulation and low temperature drift. Its zener impedance of 15 Ω is measured at 7.5 mA DC with 0.75 mA RMS 60 Hz AC superimposed, per JEDEC 5.
It operates across –65°C to +175°C storage and operating ranges, with power derating at 4 mW/°C above +50°C. Reverse leakage is specified at 2 µA @ 3 Vdc, confirming stable blocking behavior below breakdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 5.9–6.5 V @ IZT = 7.5 mA - defines regulated output range for feedback sensing |
| Zener Impedance (ZZT) | 15 Ω - ensures minimal output voltage variation under load transients |
| Temperature Coefficient | ±0.01 %/°C - enables stable reference performance across –55°C to +100°C operating range |
| Power Dissipation | 500 mW @ +50°C - supports continuous operation in compact thermal environments |
| Package | DO-213AA (MELF, SOD-80, LL34) - hermetic glass, surface-mountable, axial leadless |
| Reverse Leakage (IR) | 2 µA @ 3 Vdc - guarantees low standby current in high-impedance bias networks |
Pinout & Package
CDLL821/TR uses a two-terminal DO-213AA (MELF) glass package with cathode identified by a dark band. No leads - terminals are axial ends of cylindrical body; polarity must be observed with banded (cathode) end connected to higher potential.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground node | Connected to circuit ground or low-side reference point in shunt regulator topology |
| Cathode (banded end) | Zener breakdown terminal / regulated voltage output node | Provides stable 5.9–6.5 V reference when reverse-biased; must connect to regulated rail |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic DO-213AA glass package | Enables operation in harsh environments (high humidity, vacuum, radiation-sensitive systems) without encapsulation degradation |
| Metallurgically bonded double-plug construction | Improves long-term voltage stability and reduces parameter drift under thermal cycling |
| Temperature-compensated zener design | Maintains ±0.01 %/°C TC over –55°C to +100°C, critical for precision analog references |
| Low 15 Ω zener impedance at 7.5 mA | Minimizes output voltage sag during transient load steps in feedback control paths |
Applications
| Switch-Mode Power Supply Feedback | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Shunt-based voltage sensing in isolated flyback or forward converter secondary-side regulation. IC Role / Device Role / Timing Role: Provides precise 6.2 V reference to optocoupler input, enabling accurate output voltage tracking. Use Value: Low 15 Ω ZZT and ±0.01 %/°C TC ensure <±1% output regulation over line, load, and temperature. | Use Scenario: Biasing and reference generation for 4–20 mA transmitter front-end op-amps. IC Role / Device Role / Timing Role: Supplies stable excitation voltage to bridge sensors and reference for ADC input scaling. Use Value: Hermetic DO-213AA package withstands industrial ambient conditions while maintaining reference accuracy. |
| Medical Instrumentation Reference | Aerospace Power Monitoring |
Use Scenario: Precision voltage reference for ECG/EEG analog front-end gain calibration. IC Role / Device Role / Timing Role: Sets baseline for programmable gain amplifier offset correction and ADC full-scale reference. Use Value: ±0.01 %/°C TC and <2 µA leakage prevent measurement drift across clinical temperature ranges. | Use Scenario: On-board bus voltage monitoring in satellite power distribution units. IC Role / Device Role / Timing Role: Serves as primary shunt reference in redundant voltage supervisor circuits. Use Value: –65°C to +175°C rating and hermetic seal support extended mission life in thermal-vacuum environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C6V2 | 6.2 V nominal, 80 Ω ZZT, ±0.07 %/°C TC, SOT-23 plastic package | Higher impedance and tempco; suitable only for non-critical biasing, not precision regulation | Select CDLL821/TR where <15 Ω ZZT and ±0.01 %/°C TC are required for closed-loop stability |
| 1N821UR-1 | Identical electrical specs; MIL-PRF-19500/159 qualified, JAN/JANTXV screening available | Required for defense/aerospace programs needing military-grade traceability and screening | Choose CDLL821/TR for commercial/industrial use; select 1N821UR-1 when MIL-spec compliance is mandatory |
Compared with BZX84-C6V2 and 1N821UR-1, CDLL821/TR delivers superior zener impedance and temperature stability in a cost-optimized hermetic MELF package - ideal for industrial and medical designs requiring reliability without MIL qualification overhead.
Availability
CDLL821/TR is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor transmitters, medical instrumentation, aerospace power monitors, and precision analog reference circuits requiring stable component supply and long-term parametric consistency.
Supply support for CDLL821/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
Central Semiconductor Corp. (CDI) is a U.S.-based manufacturer specializing in discrete semiconductors, including zener, switching, and RF diodes, with emphasis on high-reliability and temperature-stable devices.
The CDLL821/TR belongs to CDI's temperature-compensated MELF zener series, engineered for precision voltage reference in demanding analog, power, and instrumentation applications where long-term stability and hermetic integrity are essential.
FAQ
What is the nominal zener voltage range of CDLL821/TR?
The CDLL821/TR has a specified zener voltage range of 5.9 V to 6.5 V at a test current of 7.5 mA. This range reflects manufacturing tolerance and allows system designers to select appropriate series resistance for target regulation voltage. The CDLL821/TR is not a fixed 6.2 V device - actual unit measurements fall within this band, and tighter tolerances require binning or alternative grades like CDLL821A (10 Ω ZZT).
Is CDLL821/TR compatible with standard SMT reflow profiles?
Yes, CDLL821/TR uses a DO-213AA (MELF) glass package rated for standard lead-free reflow profiles, including peak temperatures up to 260°C for ≤10 seconds. Its hermetic construction prevents moisture-induced popcorning. The CDLL821/TR requires careful placement due to its cylindrical shape but is fully compatible with automated pick-and-place and reflow soldering when using appropriate nozzle and vacuum tooling.
How does the temperature coefficient of CDLL821/TR compare to standard zeners?
The CDLL821/TR exhibits a temperature coefficient of ±0.01 %/°C over –55°C to +100°C - significantly tighter than typical 6.2 V zeners (e.g., ±0.07 %/°C). This is achieved via temperature-compensated double-plug construction. For designs requiring minimal drift across wide ambient ranges, the CDLL821/TR provides measurable improvement in reference stability compared to non-compensated alternatives.
Can CDLL821/TR replace 1N821UR-1 in existing designs?
CDLL821/TR shares identical electrical specifications and DO-213AA packaging with 1N821UR-1, making it a functional replacement in commercial applications. However, 1N821UR-1 carries MIL-PRF-19500/159 qualification and screening (JAN/JANTXV), while CDLL821/TR is commercial-grade. So CDLL821/TR may be substituted where military specs are not mandated - but the CDLL821/TR itself is not screened or certified to those standards.
What is the maximum power dissipation of CDLL821/TR at 100°C ambient?
CDLL821/TR has a base power rating of 500 mW at +50°C, with linear derating of 4 mW/°C above that temperature. At 100°C ambient, derating is (100 − 50) × 4 mW = 200 mW, resulting in a maximum allowable dissipation of 300 mW. This must be verified against actual PCB thermal resistance and layout - the CDLL821/TR's axial COE (~6 ppm/°C) also requires matching mounting surface expansion to avoid mechanical stress-induced parameter shift.
CDLL821/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):
- 6.2 V
- Tolerance:
- ±4.83%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 15 Ohms
- Current - Reverse Leakage @ Vr:
- 2 µA @ 3 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AA
CDLL821/TR FAQ
1.How can I place an order for CDLL821/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for CDLL821/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 CDLL821/TR reliable?
The price and inventory of CDLL821/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CDLL821/TR is usually 5 days.
3.What payment methods are accepted for CDLL821/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CDLL821/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CDLL821/TR?
CDLL821/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CDLL821/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 CDLL821/TR?
For technical support, including CDLL821/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CDLL821/TR requirements.
6.How does Aetrix verify that CDLL821/TR is sourced from the original manufacturer or authorized distributors?
All CDLL821/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 CDLL821/TR meets industry standards.
7.What is the process for return or replacement of CDLL821/TR?
All CDLL821/TR units undergo pre-shipment inspection (PSI). If there is an issue with CDLL821/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 CDLL821/TR part is unused and in its original packaging.
Return procedure for CDLL821/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CDLL821/TR Tags
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