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

Nexperia USA Inc. BZX79-C18,133

Name: BZX79-C18,133
Brand: Nexperia USA Inc.
SKU: BZX79-C18,133
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX79-C18,133

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: BZX79-C18,133.pdf

Description:: DIODE ZENER 18V 400MW ALF2

Quantity:: RFQ Add To RFQ list

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Inventory:8,747

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Product details

Overview

BZX79-C18,133 from Nexperia is a ±5% tolerance Zener voltage regulator diode with nominal 18 V breakdown voltage at 5 mA test current, 50 Ω typical differential resistance, and −12.4 mV/K temperature coefficient. It operates in low-power voltage reference and stabilization circuits, such as power supply feedback networks and analog sensor biasing, within industrial control and consumer electronics.

For engineers reviewing the BZX79-C18,133 datasheet, BZX79-C18,133 pinout, BZX79-C18,133 application, or BZX79-C18,133 equivalent, key selection criteria include Zener voltage tolerance (±5%), thermal resistance (380 K/W), non-repetitive peak reverse power (40 W), and DO-35 package compatibility with through-hole PCB assembly.

Technical Context

This device functions as a passive two-terminal voltage reference, relying on controlled avalanche or Zener breakdown in silicon PN junction under reverse bias. Its operation requires external current limiting and is specified at T_j = 25 °C with derating above Tamb = 50 °C.

It exhibits a negative temperature coefficient of −12.4 mV/K at I_Z = 5 mA, indicating decreasing Zener voltage with rising junction temperature. Capacitance is 10 pF at 1 MHz and 0 V reverse bias, supporting stable regulation in low-frequency feedback paths.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	17.6–18.4 V at I_Z = 5 mA; defines stable reference point for feedback loops
Tolerance	±5%; determines absolute accuracy band for voltage-critical biasing
Differential Resistance (r_diff)	50 Ω typical at I_Z = 5 mA; governs load regulation sensitivity to current variation
Temperature Coefficient (S_Z)	−12.4 mV/K at I_Z = 5 mA; quantifies drift per degree Celsius in precision references
Power Dissipation (P_tot)	500 mW at T_amb = 50 °C; sets maximum continuous DC power handling on standard PCB
Reverse Current (I_R)	50 nA max at V_R = 12.6 V; ensures minimal leakage in high-impedance reference nodes
Diode Capacitance (C_d)	10 pF at f = 1 MHz, V_R = 0 V; limits high-frequency noise coupling in analog circuits

Pinout & Package

Hermetically sealed axial-leaded SOD27 (DO-35) glass package with cathode indicated by a colored band. Leads are tinned copper alloy, suitable for wave or hand soldering.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / reference ground node	Connected to circuit common or lower-potential rail in shunt regulator configuration
Cathode	Zener breakdown terminal / regulated output node	Connected to input via series resistor and supplies stable 18 V to load or error amplifier

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Enables cost-effective voltage referencing where tight regulation is not required, e.g., overvoltage clamping
500 mW total power dissipation	Supports continuous operation in compact through-hole designs without heatsinking up to 50 °C ambient
Non-repetitive peak reverse power of 40 W	Provides transient surge immunity against short-duration ESD or inductive kick events
−12.4 mV/K temperature coefficient	Allows predictable drift compensation in temperature-stable reference designs using complementary components
DO-35 mechanical outline with axial leads	Ensures compatibility with legacy through-hole assembly lines and manual prototyping workflows

Applications

Power Supply Feedback Reference

Overvoltage Protection Clamp

Use Scenario: Regulating output voltage in linear or switching power supplies using TL431 or op-amp feedback.

IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 18 V setpoint to error amplifier input.

Use Value: Maintains ±5% output accuracy across line/load variations without requiring active regulation circuitry.

Use Scenario: Protecting microcontroller I/O pins from transient overvoltage during hot-plug or ESD events.

IC Role / Device Role / Timing Role: Passive clamp limiting voltage to 18.4 V maximum during surge conditions.

Use Value: Absorbs up to 40 W non-repetitive peak power for 100 μs, preventing latch-up or gate oxide damage.

Sensor Biasing Network

ADC Reference Stabilization

Use Scenario: Providing stable excitation voltage to resistive temperature detectors (RTDs) or strain gauges.

IC Role / Device Role / Timing Role: Low-noise DC reference source for bridge excitation in precision measurement front-ends.

Use Value: 10 pF capacitance and 50 Ω dynamic impedance minimize noise injection into high-gain instrumentation amplifiers.

Use Scenario: Stabilizing reference input of 12-bit SAR ADCs in data acquisition modules.

IC Role / Device Role / Timing Role: Secondary reference buffer ensuring V_REF remains within 18.4 V despite supply ripple.

Use Value: ±5% tolerance and −12.4 mV/K TC allow calibration-based correction for full-scale error < 0.5 LSB.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4746A	18 V ±5%, 1 W rating, DO-41 package, 20 Ω r_diff, +2.5 mV/K TC	Higher power handling but larger footprint; positive TC requires different compensation strategy	Select when >500 mW continuous dissipation or surface-mount avoidance is required
BZX79-B18,133	18 V ±2%, same DO-35 package, 50 Ω r_diff, −12.4 mV/K TC	Same thermal and capacitive behavior, tighter voltage tolerance for higher-accuracy references	Select when system-level calibration margin demands <±2% initial error

Compared with BZX79-C18,133, the 1N4746A offers double the power rating but introduces positive temperature drift and incompatible packaging, while BZX79-B18,133 delivers identical thermal and electrical dynamics with improved voltage accuracy-making it a drop-in upgrade where tighter regulation is needed without layout change.

Availability

BZX79-C18,133 is available at Aetrix Electronics and suitable for industrial power supplies, consumer appliance control boards, and automotive body electronics requiring stable component supply with long-term obsolescence management.

Supply support for BZX79-C18,133 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

Nexperia is a global leader in discrete semiconductors, formed in 2017 from the former NXP Standard Products division, specializing in high-volume, high-reliability components for automotive and industrial markets.

BZX79-C18,133 belongs to the BZX79 series of low-power Zener diodes designed specifically for cost-sensitive voltage reference and protection roles in mass-produced consumer and industrial electronics.

FAQ

What is the recommended series resistor value for BZX79-C18,133 in a 24 V supply shunt regulator?

For reliable operation at 5 mA Zener current with 24 V input, a 1.2 kΩ ±1% resistor provides 18 V regulation while dissipating 30 mW. This ensures minimum current stays above 1 mA across load and temperature extremes, maintaining regulation stability per datasheet Fig.5 and Table 1.

Can BZX79-C18,133 be used in parallel for higher power handling?

No-Zener diodes exhibit manufacturing spread in V_Z and temperature coefficient, causing current hogging and thermal runaway when paralleled. The datasheet specifies single-device operation only; use a higher-rated part like 1N4746A instead for >500 mW needs.

Is the cathode marking band polarity consistent across all DO-35 Zeners from Nexperia?

Yes-the colored band always denotes the cathode terminal across all BZX79 series devices, including BZX79-C18,133. This matches JEDEC DO-35 standard and is confirmed in the package outline diagram (page 8) and symbol (Fig.1) of the official Nexperia datasheet.

Does BZX79-C18,133 meet AEC-Q200 requirements for automotive use?

No-BZX79-C18,133 is not AEC-Q200 qualified. It is rated for industrial temperature range (−65 °C to +200 °C) but lacks the stress testing, lot traceability, and failure rate validation required for automotive applications. Nexperia's Automotive-grade equivalents carry "A" suffixes (e.g., BZX79-C18A).

BZX79-C18,133 Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Cut Tape (CT)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 18 V

Tolerance:: ±5%

Power - Max:: 400 mW

Impedance (Max) (Zzt):: 45 Ohms

Current - Reverse Leakage @ Vr:: 50 nA @ 12.6 V

Voltage - Forward (Vf) (Max) @ If:: 900 mV @ 10 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: ALF2

BZX79-C18,133 FAQ

1.How can I place an order for BZX79-C18,133 through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX79-C18,133 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 BZX79-C18,133 reliable?

The price and inventory of BZX79-C18,133 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79-C18,133 is usually 5 days.

3.What payment methods are accepted for BZX79-C18,133?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79-C18,133 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX79-C18,133?

BZX79-C18,133 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX79-C18,133 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 BZX79-C18,133?

For technical support, including BZX79-C18,133 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79-C18,133 requirements.

6.How does Aetrix verify that BZX79-C18,133 is sourced from the original manufacturer or authorized distributors?

All BZX79-C18,133 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 BZX79-C18,133 meets industry standards.

7.What is the process for return or replacement of BZX79-C18,133?

All BZX79-C18,133 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79-C18,133, 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 BZX79-C18,133 part is unused and in its original packaging.

Return procedure for BZX79-C18,133:

1.Submit a request within 90 days.

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

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