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

Taiwan Semiconductor Corporation BZX85C18 R0G

Name: BZX85C18 R0G
Brand: Taiwan Semiconductor Corporation
SKU: BZX85C18 R0G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX85C18 R0G

Manufacturer:: Taiwan Semiconductor Corporation

Category:: Single Zener Diodes

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

Datasheet:: BZX85C18 R0G.pdf

Description:: DIODE ZENER 18V 1.3W DO204AL

Quantity:: RFQ Add To RFQ list

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Inventory:9,260

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Product details

Overview

BZX85C18 R0G from Taiwan Semiconductor is a 1.3W, ±5% tolerance Zener diode with nominal zener voltage of 18 V, tested at 20 mA, zener impedance of 500 Ω at IZT, and maximum leakage current of 0.5 µA at 13 V, used for precision low-voltage stabilization in DC/DC converters and power adapters.

For engineers reviewing the BZX85C18 R0G datasheet, BZX85C18 R0G pinout, BZX85C18 R0G application, or BZX85C18 R0G equivalent, key selection criteria include zener voltage tolerance, power dissipation capability, thermal resistance, junction temperature rating, and DO-41 package compatibility with through-hole PCB assembly.

Technical Context

This discrete Zener diode operates as a two-terminal voltage reference device, regulating reverse-biased voltage across its cathode–anode terminals with specified breakdown characteristics at defined test currents. Its 1.3 W power rating and 130 °C/W junction-to-ambient thermal resistance define safe continuous operation limits under natural convection.

The device features hermetically sealed glass construction, pure tin-plated leads compliant with J-STD-002 solderability, and polarity indicated by a visible cathode band - all supporting reliable long-term performance in industrial-grade power supply circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z (Nominal)	18 V - precise reverse breakdown voltage at 20 mA test current, enabling stable reference generation
V_Z Tolerance	±5% - ensures voltage consistency across production lots for predictable circuit behavior
P_D	1.3 W - maximum continuous power dissipation at 25°C ambient, limiting usable current in regulation
Z_ZT	500 Ω - dynamic impedance at 20 mA, determining output voltage variation under load changes
I_R @ V_R	0.5 µA at 13 V - low leakage ensures minimal error current in high-impedance reference paths
T_J max	+200°C - high junction temperature rating supports operation in thermally demanding environments
R_θJA	130 °C/W - thermal resistance defines required heatsinking or board copper area for safe derating

Pinout & Package

Package: DO-41 axial-leaded glass package with cathode band marking; lead finish: pure tin, solderable per J-STD-002; weight: ~242 mg.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Reference ground node	Connected to circuit ground or lower-potential node in reverse-bias regulation configuration
Cathode	Zener breakdown terminal / Voltage reference output	Connected to regulated voltage rail; cathode band visually identifies this terminal on the body

Key Features

Feature	Design Value
Hermetically sealed glass construction	Prevents moisture ingress and long-term parameter drift in humid or harsh environments
±5% V_Z tolerance	Reduces need for post-assembly trimming in voltage reference designs
DO-41 mechanical standardization	Ensures compatibility with legacy through-hole assembly equipment and footprint libraries
RoHS-compliant green compound	Meets environmental compliance requirements without sacrificing thermal or electrical performance

Applications

Low-Voltage Stabilizers	On-Board DC/DC Converters
Use Scenario: Providing stable bias voltage for op-amp input stages or microcontroller reset circuits in battery-powered devices. IC Role / Device Role / Timing Role: Zener reference element establishing fixed voltage threshold independent of supply variation. Use Value: Maintains 18 V reference with ≤±0.9 V deviation, ensuring consistent logic-level detection across temperature.	Use Scenario: Generating isolated feedback reference for secondary-side regulation in isolated flyback or forward converters. IC Role / Device Role / Timing Role: Precision shunt reference connected to optocoupler LED anode for closed-loop voltage sensing. Use Value: Enables accurate 18 V output regulation with <0.5 µA leakage, minimizing feedback path error.
Power Adapters	Lighting Applications
Use Scenario: Overvoltage clamping and auxiliary supply regulation in AC/DC wall adapters for consumer electronics. IC Role / Device Role / Timing Role: Shunt protection device limiting transient voltage spikes on low-power auxiliary rails. Use Value: Absorbs up to 1.3 W during overvoltage events while maintaining stable 18 V clamp level.	Use Scenario: Current regulation and open-circuit protection in LED driver constant-voltage stages. IC Role / Device Role / Timing Role: Voltage clamp preventing excessive forward voltage across parallel LED strings. Use Value: Limits string voltage to 19.1 V max, protecting LEDs from overvoltage stress during startup or fault conditions.

Low-Voltage Stabilizers

On-Board DC/DC Converters

Use Scenario: Providing stable bias voltage for op-amp input stages or microcontroller reset circuits in battery-powered devices.

IC Role / Device Role / Timing Role: Zener reference element establishing fixed voltage threshold independent of supply variation.

Use Value: Maintains 18 V reference with ≤±0.9 V deviation, ensuring consistent logic-level detection across temperature.

Use Scenario: Generating isolated feedback reference for secondary-side regulation in isolated flyback or forward converters.

IC Role / Device Role / Timing Role: Precision shunt reference connected to optocoupler LED anode for closed-loop voltage sensing.

Use Value: Enables accurate 18 V output regulation with <0.5 µA leakage, minimizing feedback path error.

Power Adapters

Lighting Applications

Use Scenario: Overvoltage clamping and auxiliary supply regulation in AC/DC wall adapters for consumer electronics.

IC Role / Device Role / Timing Role: Shunt protection device limiting transient voltage spikes on low-power auxiliary rails.

Use Value: Absorbs up to 1.3 W during overvoltage events while maintaining stable 18 V clamp level.

Use Scenario: Current regulation and open-circuit protection in LED driver constant-voltage stages.

IC Role / Device Role / Timing Role: Voltage clamp preventing excessive forward voltage across parallel LED strings.

Use Value: Limits string voltage to 19.1 V max, protecting LEDs from overvoltage stress during startup or fault conditions.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4746A	Same 18 V nominal V_Z, but ±5% tolerance and 1 W power rating (vs. 1.3 W)	Limited to lower-power reference use; not suitable for sustained 1.3 W dissipation	Select BZX85C18 R0G when higher power margin or extended thermal endurance is required
MMBZ5246B	SMD SOT-23 package, same 18 V V_Z, ±5%, but only 0.35 W rating and different thermal profile	Designed for space-constrained PCBs; unsuitable for through-hole or high-power layouts	Choose BZX85C18 R0G for through-hole assembly, higher reliability in industrial power supplies

Compared with 1N4746A and MMBZ5246B, BZX85C18 R0G delivers superior thermal robustness (1.3 W, +200°C T_J) and proven DO-41 mechanical reliability - critical for adapter and converter designs requiring long-term stability under thermal cycling.

Availability

BZX85C18 R0G is available at Aetrix Electronics and suitable for low-voltage stabilizers, on-board DC/DC converters, and power adapters requiring stable component supply with full RoHS compliance and traceable sourcing.

Supply support for BZX85C18 R0G 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 semiconductor manufacturer specializing in discrete power devices, analog ICs, and protection components for industrial and consumer markets.

The BZX85C series belongs to TSC's general-purpose Zener diode product line, engineered for cost-effective, high-reliability voltage reference and regulation in power supply and adapter applications.

FAQ

What is the nominal zener voltage and tolerance of BZX85C18 R0G?

The BZX85C18 R0G has a nominal zener voltage of 18 V with a standard tolerance of ±5%, meaning the actual measured V_Z falls between 16.8 V and 19.1 V at 20 mA test current. This tolerance is confirmed in the Electrical Specifications table of the official Taiwan Semiconductor datasheet (Version H2301), and applies directly to the BZX85C18 R0G part number.

What is the maximum power dissipation rating for BZX85C18 R0G?

The BZX85C18 R0G is rated for 1.3 W maximum power dissipation at 25°C ambient temperature, as specified in the Absolute Maximum Ratings section. Derating is required above 25°C per the device's 130 °C/W junction-to-ambient thermal resistance - for example, at 75°C ambient, the usable power drops to approximately 0.95 W. This rating is validated for the DO-41 package under natural convection.

Does BZX85C18 R0G have RoHS compliance and lead-free construction?

Yes, BZX85C18 R0G is RoHS compliant and uses green compound encapsulation with pure tin-plated leads, meeting J-STD-002 solderability requirements. The datasheet explicitly states "RoHS Compliant" under FEATURES and confirms lead-free plating in the MECHANICAL DATA section - no exemptions or exceptions apply to this orderable part.

What is the zener impedance of BZX85C18 R0G and how is it measured?

The zener impedance (Z_ZT) of BZX85C18 R0G is 500 Ω, measured at the 20 mA test current (I_ZT). Per datasheet Note 4, this value is derived from the AC voltage response when a 60-cycle sine wave with RMS amplitude equal to 10% of I_ZT is superimposed on the DC bias - a standardized method ensuring repeatable measurement across production lots of BZX85C18 R0G.

What package type and marking does BZX85C18 R0G use?

BZX85C18 R0G uses the DO-41 axial-leaded glass package with cathode polarity indicated by a visible band. Its marking code is "BZX85C18", printed on the body, and the "R0G" suffix denotes DO-41 packaging in 5,000-piece 14-inch reels - consistent with Taiwan Semiconductor's Ordering Information table for the BZX85C series.

BZX85C18 R0G 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):: 18 V

Tolerance:: ±5%

Power - Max:: 1.3 W

Impedance (Max) (Zzt):: 20 Ohms

Current - Reverse Leakage @ Vr:: 500 nA @ 13 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)

BZX85C18 R0G FAQ

1.How can I place an order for BZX85C18 R0G through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX85C18 R0G 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 BZX85C18 R0G reliable?

The price and inventory of BZX85C18 R0G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C18 R0G is usually 5 days.

3.What payment methods are accepted for BZX85C18 R0G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C18 R0G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX85C18 R0G?

BZX85C18 R0G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX85C18 R0G 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 BZX85C18 R0G?

For technical support, including BZX85C18 R0G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C18 R0G requirements.

6.How does Aetrix verify that BZX85C18 R0G is sourced from the original manufacturer or authorized distributors?

All BZX85C18 R0G 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 BZX85C18 R0G meets industry standards.

7.What is the process for return or replacement of BZX85C18 R0G?

All BZX85C18 R0G units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C18 R0G, 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 BZX85C18 R0G part is unused and in its original packaging.

Return procedure for BZX85C18 R0G:

1.Submit a request within 90 days.

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

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