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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Taiwan Semiconductor Corporation BZX85C30

Name: BZX85C30
Brand: Taiwan Semiconductor Corporation
SKU: BZX85C30
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX85C30

Manufacturer:: Taiwan Semiconductor Corporation

Category:: Single Zener Diodes

Package:: DO-204AL, DO-41, Axial

Datasheet:: BZX85C30.pdf

Description:: DIODE ZENER 30V 1.3W DO204AL

Quantity:: RFQ Add To RFQ list

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Inventory:6,610

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Product details

Overview

BZX85C30 from Taiwan Semiconductor is a 30V ±5% Zener diode in DO-41 package, rated for 1.3W power dissipation and operating up to +200°C junction temperature; it provides stable voltage reference in low-power DC/DC converters, LED drivers, and adapter circuits.

For engineers reviewing the BZX85C30 datasheet, BZX85C30 pinout, BZX85C30 application, or BZX85C30 equivalent, key selection criteria include its 30V nominal Zener voltage (28.0–32.0V range), 8mA test current, 1000Ω dynamic impedance at IZT, 0.25mA knee current, and 22V reverse leakage threshold.

Technical Context

The BZX85C30 operates as a single-die, silicon planar Zener diode with hermetically sealed glass DO-41 packaging and cathode-band polarity marking. Its Zener voltage is specified under 10ms pulse test conditions and exhibits ±5% tolerance across production lots.

Thermal performance is defined by a junction-to-ambient thermal resistance of 130°C/W, enabling reliable operation in ambient temperatures from –65°C to +200°C when mounted on standard PCBs without heatsinking.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z Nominal	30 V - precise regulation point for voltage reference or clamping
V_Z Range	28.0–32.0 V - ensures functional margin within ±5% tolerance at 8 mA
P_D	1.3 W - maximum continuous power dissipation at 25°C ambient
Z_ZT	1000 Ω - dynamic impedance at 8 mA test current, impacts regulation stability
I_ZK	0.25 mA - minimum knee current for onset of Zener conduction
T_J Max	+200 °C - enables high-temperature industrial and automotive under-hood use
R_θJA	130 °C/W - defines thermal derating slope for PCB-mounted operation

Pinout & Package

Package: DO-41 - axial-leaded, hermetically sealed glass case with pure tin-plated solderable leads per J-STD-002; cathode identified by black band; weight ≈242 mg.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward-biased terminal during conduction	Connected to lower-potential node in reverse-bias regulation configuration
Cathode	Zener breakdown terminal	Marked with band; connected to higher-potential node to enable reverse-bias voltage clamping

Key Features

Feature	Design Value
±5% V_Z tolerance	Enables predictable regulation without post-production trimming in cost-sensitive designs
Hermetically sealed glass	Ensures long-term parameter stability and moisture resistance in harsh environments
1.3W power rating	Supports moderate-current shunt regulation without external heat sinking
DO-41 mechanical standard	Guarantees compatibility with legacy through-hole assembly lines and hand-soldering workflows
RoHS compliant	Meets global environmental compliance requirements for commercial and industrial shipments

Applications

LED Driver Reference	Adapter Voltage Clamp
Use Scenario: Stabilizing bias voltage for constant-current LED driver ICs in retrofit lamps. IC Role / Device Role / Timing Role: Voltage reference element setting feedback threshold for current-sense amplifier. Use Value: Maintains ±5% output current accuracy over temperature using BZX85C30's stable 30V Zener point and low 1000Ω impedance.	Use Scenario: Overvoltage protection in wall-mount AC/DC adapters supplying 24V systems. IC Role / Device Role / Timing Role: Shunt clamp limiting secondary-side rail to safe level during transient surges. Use Value: Activates reliably at 28.0–32.0V range to divert excess energy before downstream regulators fail.
On-board DC/DC Converter	Industrial Sensor Excitation
Use Scenario: Providing isolated reference voltage for feedback divider in 48V-to-5V buck converter. IC Role / Device Role / Timing Role: Precision shunt reference stabilizing optocoupler input side voltage. Use Value: Delivers stable 30V reference despite input ripple, enabled by BZX85C30's 130°C/W thermal resistance and +200°C T_J rating.	Use Scenario: Supplying excitation voltage to 4–20mA loop-powered pressure sensors. IC Role / Device Role / Timing Role: Fixed-voltage source powering sensor bridge and signal conditioning circuitry. Use Value: Ensures consistent sensor output linearity by maintaining regulated 30V supply even with varying loop load.

LED Driver Reference

Adapter Voltage Clamp

Use Scenario: Stabilizing bias voltage for constant-current LED driver ICs in retrofit lamps.

IC Role / Device Role / Timing Role: Voltage reference element setting feedback threshold for current-sense amplifier.

Use Value: Maintains ±5% output current accuracy over temperature using BZX85C30's stable 30V Zener point and low 1000Ω impedance.

Use Scenario: Overvoltage protection in wall-mount AC/DC adapters supplying 24V systems.

IC Role / Device Role / Timing Role: Shunt clamp limiting secondary-side rail to safe level during transient surges.

Use Value: Activates reliably at 28.0–32.0V range to divert excess energy before downstream regulators fail.

On-board DC/DC Converter

Industrial Sensor Excitation

Use Scenario: Providing isolated reference voltage for feedback divider in 48V-to-5V buck converter.

IC Role / Device Role / Timing Role: Precision shunt reference stabilizing optocoupler input side voltage.

Use Value: Delivers stable 30V reference despite input ripple, enabled by BZX85C30's 130°C/W thermal resistance and +200°C T_J rating.

Use Scenario: Supplying excitation voltage to 4–20mA loop-powered pressure sensors.

IC Role / Device Role / Timing Role: Fixed-voltage source powering sensor bridge and signal conditioning circuitry.

Use Value: Ensures consistent sensor output linearity by maintaining regulated 30V supply even with varying loop load.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N5257B	Same 30V nominal, ±5%, but 0.5W rating and DO-35 package	Limited to lower-power references; unsuitable for 1.3W dissipation scenarios	Select only if thermal budget allows <0.5W operation and board space favors smaller DO-35
MMBZ5257BS	30V, ±5%, SOT-23 package, 200mW rating	Surface-mount only; not interchangeable in through-hole layouts	Choose for space-constrained PCBs where reflow assembly replaces through-hole processes

Compared with 1N5257B and MMBZ5257BS, the BZX85C30 offers 2.6× higher power handling and DO-41 mechanical compatibility-critical for industrial adapters and DC/DC converters requiring robust thermal margin and legacy assembly support.

Availability

BZX85C30 is available at Aetrix Electronics and suitable for LED driver references, adapter voltage clamps, and on-board DC/DC converters requiring stable component supply with full traceability and long-lifecycle assurance.

Supply support for BZX85C30 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial and consumer markets since 1979.

The BZX85C series is part of TSC's general-purpose Zener diode product line, engineered for cost-effective, high-reliability voltage regulation and clamping in power supplies, lighting, and industrial control systems.

FAQ

What is the Zener voltage tolerance of the BZX85C30?

The BZX85C30 has a nominal Zener voltage of 30 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 28.0 V and 32.0 V when tested at 8 mA under pulse conditions. This tolerance is guaranteed across production lots and supports predictable design margins in voltage reference circuits without calibration.

What is the maximum power dissipation for the BZX85C30?

The BZX85C30 is rated for 1.3 W maximum power dissipation at 25°C ambient temperature. Derating is required above this temperature, following the 130°C/W junction-to-ambient thermal resistance. At 75°C ambient, the usable power drops to approximately 0.75 W, making thermal layout critical in high-density or high-temperature applications.

Does the BZX85C30 have RoHS compliance documentation?

Yes, the BZX85C30 is RoHS compliant, as confirmed in Taiwan Semiconductor's official documentation (Version H2301). It contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE), meeting EU Directive 2011/65/EU requirements for commercial and industrial shipments.

What package type does the BZX85C30 use?

The BZX85C30 uses the DO-41 axial-leaded package: hermetically sealed glass body, pure tin-plated leads compliant with J-STD-002, cathode indicated by a black band, and mechanical dimensions conforming to HQ2SD07-DO41-059 REV A. This package supports manual and automated through-hole assembly.

How does the BZX85C30 compare to the BZX85C27 in terms of Zener impedance?

The BZX85C30 has a Zener impedance (Z_ZT) of 1000 Ω at 8 mA test current, while the BZX85C27 specifies 750 Ω at 30 mA. The higher impedance reflects the physics of higher-voltage Zeners and means the BZX85C30 exhibits greater voltage variation under load changes-designers should account for this in precision reference applications.

BZX85C30 Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Series:: -

Package/Case:: DO-204AL, DO-41, Axial

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 30 V

Tolerance:: ±5%

Power - Max:: 1.3 W

Impedance (Max) (Zzt):: 30 Ohms

Current - Reverse Leakage @ Vr:: 500 nA @ 22 V

Voltage - Forward (Vf) (Max) @ If:: 1.2 V @ 10 mA

Operating Temperature:: -65°C ~ 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-204AL (DO-41)

BZX85C30 FAQ

1.How can I place an order for BZX85C30 through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX85C30 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 BZX85C30 reliable?

The price and inventory of BZX85C30 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C30 is usually 5 days.

3.What payment methods are accepted for BZX85C30?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C30 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX85C30?

BZX85C30 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX85C30 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 BZX85C30?

For technical support, including BZX85C30 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C30 requirements.

6.How does Aetrix verify that BZX85C30 is sourced from the original manufacturer or authorized distributors?

All BZX85C30 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 BZX85C30 meets industry standards.

7.What is the process for return or replacement of BZX85C30?

All BZX85C30 units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C30, 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 BZX85C30 part is unused and in its original packaging.

Return procedure for BZX85C30:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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