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onsemi BZX55C20_T50R
- Part No.:
- BZX55C20_T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX55C20_T50R.pdf
- Description:
- DIODE ZENER 20V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:7,374
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Product details
Overview
BZX55C20_T50R from Fairchild Semiconductor is a 20 V, ±5% tolerance Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 75°C with 55 Ω dynamic impedance at 5 mA test current and 0.1 μA reverse leakage at 15.2 V. It regulates voltage in low-power reference and protection circuits such as power supply feedback paths and overvoltage clamping.
For engineers reviewing the BZX55C20_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, junction temperature range, and DO-35 mechanical compatibility with through-hole PCB layouts.
Technical Context
The BZX55C20_T50R operates as a silicon planar Zener diode with sharp reverse breakdown characteristics, designed for precision DC voltage regulation and transient suppression. Its 20 V nominal zener voltage is specified at 5 mA test current with 55 Ω dynamic impedance (ZZ), ensuring stable regulation under moderate load variations.
It supports operation across –65°C to +200°C junction and storage temperature range, with 4.0 mW/°C linear derating above 75°C ambient. Reverse leakage remains ≤0.1 μA at VR = 15.2 V, enabling low-quiescent-current biasing in high-impedance sensing nodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 20 V nominal, min 19.0 V / max 21.1 V at IZ = 5 mA - defines regulated output voltage window under standard test conditions |
| Tolerance | ±5% - ensures predictable voltage accuracy without post-selection trimming |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C, 3/8″ lead length - sets maximum continuous power handling before thermal derating applies |
| Dynamic Impedance (ZZ) | 55 Ω @ IZ = 5 mA - determines regulation stiffness and output voltage variation under load changes |
| Reverse Leakage (IR) | ≤0.1 μA @ VR = 15.2 V - enables use in ultra-low-current bias networks without significant error |
| Junction Temp Range | –65°C to +200°C - supports operation in automotive under-hood, industrial, and aerospace environments |
| Forward Voltage (VF) | ≤1.3 V @ IF = 100 mA - confirms standard silicon diode conduction behavior in forward-biased configurations |
Pinout & Package
DO-35 glass axial package with cathode band marking; leads are unmarked anode and banded cathode terminals. No internal bonding wires or multi-terminal structure - two-terminal device with polarity-sensitive mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener breakdown reference node | Connected to lower-potential side of circuit; reverse-biased configuration places cathode at higher potential for regulation |
| Cathode | Zener breakdown terminal / regulated output node | Marked with color band; connected to regulated rail or feedback point; carries full zener current during regulation |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Eliminates need for external trimming in cost-sensitive voltage reference designs |
| 500 mW power rating at 75°C | Supports robust operation in compact enclosures with limited airflow |
| DO-35 glass package | Enables manual soldering, wave soldering, and long-term hermetic reliability in humid environments |
| –65°C to +200°C operating range | Validates use in extended-temperature industrial control and automotive engine management systems |
| Low 0.1 μA leakage at 15.2 V | Minimizes loading error in high-impedance voltage divider or sensor bias applications |
Applications
| Power Supply Feedback Reference | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Used in TL431-based adjustable SMPS feedback loops to set precise output voltage thresholds. IC Role / Device Role / Timing Role: Provides stable 20 V reference for optocoupler input biasing and error amplifier threshold setting. Use Value: Maintains ±5% output regulation accuracy across line/load/temperature without active compensation. | Use Scenario: Placed across microcontroller I/O pins to limit transient overvoltage from ESD or inductive kickback. IC Role / Device Role / Timing Role: Acts as passive shunt clamp, conducting only when voltage exceeds 21.1 V to protect downstream logic inputs. Use Value: Limits peak clamped voltage to ≤21.1 V while drawing <1 μA at normal operating voltage (3.3 V or 5 V). |
| Temperature-Stable Bias Network | Low-Power Sensor Excitation |
Use Scenario: Supplies fixed bias to thermistor or RTD measurement bridges in industrial temperature transmitters. IC Role / Device Role / Timing Role: Delivers stable 20 V excitation independent of supply ripple or drift, leveraging low tempco of Zener region. Use Value: Enables <0.1% full-scale error contribution from reference stability over –40°C to +85°C ambient. | Use Scenario: Powers low-current analog sensors (e.g., piezoresistive pressure elements) requiring clean, constant-voltage excitation. IC Role / Device Role / Timing Role: Functions as low-noise, low-drift voltage source with minimal quiescent current draw (≤0.1 μA standby leakage). Use Value: Reduces sensor self-heating and improves signal-to-noise ratio in battery-powered IoT endpoints. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4744A | 20 V nominal, ±5%, DO-41 package, 1 W power rating, 22 Ω ZZ @ 25 mA | Higher power handling but larger footprint; requires higher test current for spec compliance | Select when >500 mW dissipation or improved thermal margin is required |
| BZX55C20-TR | Identical electrical specs and DO-35 package; tape-and-reel packaging variant of same die | No functional difference; optimized for automated SMT placement with reel delivery | Select for high-volume production using pick-and-place equipment |
Compared with BZX55C20_T50R, the 1N4744A offers higher power capacity but demands larger board area and different thermal design, while the BZX55C20-TR provides identical performance in tape-and-reel format for automated assembly-no electrical or mechanical redesign needed.
Availability
BZX55C20_T50R is available at Aetrix Electronics and suitable for power supply feedback references, overvoltage clamping circuits, and low-power sensor excitation requiring stable component supply and consistent DO-35 mechanical form factor.
Supply support for BZX55C20_T50R 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.
The BZX55 series belongs to Fairchild's general-purpose Zener diode product line, engineered for cost-effective, reliable voltage regulation and protection in consumer, industrial, and computing applications.
FAQ
What is the nominal zener voltage and tolerance of BZX55C20_T50R?
The BZX55C20_T50R has a nominal zener voltage of 20 V with a guaranteed tolerance of ±5%, meaning the actual measured VZ falls between 19.0 V and 21.1 V when tested at 5 mA. This tolerance is factory-trimmed and does not require external calibration. The BZX55C20_T50R maintains this specification across its full operating temperature range and is validated per Fairchild's Rev. D1 datasheet.
What package type and marking does BZX55C20_T50R use?
BZX55C20_T50R uses the DO-35 glass axial package with a cathode band marking. The top mark consists of three lines: Fairchild logo (F), "5C" (device family identifier), and "20" (voltage rating). This matches the standardized marking scheme defined in the BZX55C2V4–BZX55C56 datasheet, confirming authenticity and correct voltage binning for the BZX55C20_T50R.
How does thermal derating affect BZX55C20_T50R's power handling?
BZX55C20_T50R is rated for 500 mW at lead temperature ≤75°C with 3/8″ lead length; above that, it derates linearly at 4.0 mW/°C. At 100°C lead temperature, usable power drops to 400 mW. This derating must be applied using actual measured lead temperature-not ambient-since heat flows primarily through the leads. The BZX55C20_T50R's DO-35 package relies on lead conduction for thermal management, not PCB copper area.
What is the maximum reverse leakage current for BZX55C20_T50R, and at what voltage is it specified?
The BZX55C20_T50R exhibits ≤0.1 μA reverse leakage current at VR = 15.2 V (i.e., 76% of nominal VZ). This value is measured at 25°C and remains valid up to 125°C per datasheet notes. Such low leakage makes the BZX55C20_T50R suitable for high-impedance bias networks where even nanoamp-level currents would introduce measurable error-critical in precision sensor interfaces using the BZX55C20_T50R.
Can BZX55C20_T50R replace BZX55C20-TR in a design?
Yes, BZX55C20_T50R and BZX55C20-TR share identical electrical specifications, DO-35 package dimensions, and marking layout-the only difference is packaging format (ammo pack vs. tape-and-reel). No circuit or layout changes are required when substituting BZX55C20_T50R for BZX55C20-TR. Both are manufactured from the same die lot and meet the same Fairchild BZX55C2V4–BZX55C56 Rev. D1 specification, ensuring full functional equivalence for the BZX55C20_T50R.
BZX55C20_T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 20 V
- Tolerance:
- ±6%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 55 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 15 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.3 V @ 100 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
BZX55C20_T50R FAQ
1.How can I place an order for BZX55C20_T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX55C20_T50R 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 BZX55C20_T50R reliable?
The price and inventory of BZX55C20_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX55C20_T50R is usually 5 days.
3.What payment methods are accepted for BZX55C20_T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX55C20_T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX55C20_T50R?
BZX55C20_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX55C20_T50R 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 BZX55C20_T50R?
For technical support, including BZX55C20_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX55C20_T50R requirements.
6.How does Aetrix verify that BZX55C20_T50R is sourced from the original manufacturer or authorized distributors?
All BZX55C20_T50R 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 BZX55C20_T50R meets industry standards.
7.What is the process for return or replacement of BZX55C20_T50R?
All BZX55C20_T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX55C20_T50R, 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 BZX55C20_T50R part is unused and in its original packaging.
Return procedure for BZX55C20_T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX55C20_T50R Tags
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MMBZ5240B-7-F
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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