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Nexperia USA Inc. BZX79-C18,143
- Part No.:
- BZX79-C18,143
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79-C18,143.pdf
- Description:
- DIODE ZENER 18V 400MW ALF2
- Quantity:
- Payment:
- Shipping:
Inventory:8,366
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Product details
Overview
BZX79-C18,143 from Nexperia is a ±5% tolerance Zener voltage regulator diode with nominal working voltage 18 V at 5 mA test current, 50 Ω typical differential resistance, and 12.4 mV/K temperature coefficient. It delivers stable low-power voltage reference in compact DO-35 (SOD27) glass package, rated for 500 mW total power dissipation at 50 °C ambient, and used in precision analog biasing and supply rail clamping.
For engineers reviewing the BZX79-C18,143 datasheet, BZX79-C18,143 pinout, BZX79-C18,143 application, or BZX79-C18,143 equivalent, this page provides verified electrical parameters, thermal behavior, reverse leakage limits, junction-to-ambient thermal resistance, and validated alternative parts for voltage reference design.
Technical Context
This Zener diode operates in reverse breakdown mode to maintain a stable DC voltage across its terminals under varying load or input conditions. Its 18 V nominal regulation is specified at IZtest = 5 mA, with differential resistance of ≤225 Ω ensuring minimal output voltage variation with current changes.
The device exhibits a positive temperature coefficient of +12.4 mV/K at 5 mA, enabling predictable drift compensation in temperature-sensitive references. Its non-repetitive peak reverse power dissipation is rated at 40 W for 100 μs pulses, supporting transient overvoltage protection in low-energy circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VZ) | 17.6 V to 18.4 V at IZ = 5 mA - defines regulated output range for reference stability |
| Differential Resistance (rdif) | ≤225 Ω max at IZ = 5 mA - determines load regulation error sensitivity |
| Temperature Coefficient (SZ) | +12.4 mV/K typical at IZ = 5 mA - quantifies voltage drift per degree Celsius |
| Total Power Dissipation (Ptot) | 500 mW at Tamb = 50 °C - sets maximum continuous DC power handling |
| Reverse Current (IR) | ≤50 nA at VR = 12.6 V (0.7 × VZnom) - ensures low leakage in high-impedance bias networks |
| Junction-to-Ambient Rth | 380 K/W - defines thermal rise per watt under standard PCB mounting |
Pinout & Package
Hermetically sealed axial-leaded glass package per SOD27 (DO-35) outline: 4.25 mm body length, 1.85 mm diameter, 25.4 mm lead spacing, cathode indicated by black band. Lead material: tin-plated copper alloy.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to ground or lower potential in shunt regulator configuration |
| Cathode | Reverse breakdown terminal / regulated output node | Provides stable 18 V reference when biased through series resistor into load |
Key Features
| Feature | Design Value |
|---|---|
| ±5% voltage tolerance | Enables cost-effective selection where tight regulation is not required, e.g., non-critical biasing |
| 500 mW power rating | Supports operation up to ~27.8 mA at 18 V without derating below 50 °C ambient |
| Non-repetitive 40 W surge capability | Withstands short-duration transients (e.g., ESD or switching spikes) without degradation |
| Low 50 nA reverse leakage at 12.6 V | Maintains accuracy in high-impedance feedback paths and battery-powered sensor references |
Applications
| Power Supply Rail Clamping | ADC Reference Stabilization |
|---|---|
Use Scenario: Clamp 24 V industrial supply rail to prevent overvoltage damage to downstream 18 V logic or analog circuitry. IC Role / Device Role / Timing Role: Shunt regulator providing passive overvoltage protection by conducting excess current above 18 V threshold. Use Value: Limits transient excursions to ≤18.4 V, preserving signal integrity and preventing latch-up in connected ICs. | Use Scenario: Provide stable 18 V reference for 12-bit SAR ADC requiring <0.1% full-scale drift over temperature. IC Role / Device Role / Timing Role: Precision voltage reference source for ADC VREF input, minimizing code-width variation. Use Value: Delivers ±0.9% initial accuracy and +12.4 mV/K drift, enabling calibrated offset correction in firmware. |
| Op-Amp Bias Network | Microcontroller Reset Circuit |
Use Scenario: Set common-mode voltage for rail-to-rail op-amp input stage operating from single 20 V supply. IC Role / Device Role / Timing Role: DC bias point generator establishing mid-supply reference for differential input pairs. Use Value: Provides low-noise, low-drift 18 V node with <50 nA leakage, minimizing input offset current errors. | Use Scenario: Generate clean reset threshold for 3.3 V microcontroller powered via 18 V LDO with brown-out detection. IC Role / Device Role / Timing Role: Voltage threshold detector feeding comparator input to assert reset when supply drops below 17.6 V. Use Value: Ensures deterministic reset activation within ±0.4 V window, avoiding false triggers during supply ramp-up. |
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 rdif, −2 mV/K tempco | Higher power handling but larger footprint and negative tempco unsuitable for drift-matching | Select when >500 mW continuous dissipation is required and board space allows DO-41 |
| BZX84-C18 | 18 V ±5%, SOT-23 package, 300 mW rating, 40 Ω rdif, +12 mV/K tempco | Surface-mount compatible but lower power rating and higher thermal resistance on PCB | Select for automated assembly and space-constrained designs where 300 mW suffices |
Compared with BZX79-C18,143, the 1N4746A offers higher power margin but requires layout revision for DO-41; the BZX84-C18 enables SMT production yet demands careful thermal relief design to avoid exceeding 300 mW derating.
Availability
BZX79-C18,143 is available at Aetrix Electronics and suitable for industrial power supply clamping, analog sensor biasing, microcontroller reset conditioning, and precision reference generation requiring stable component supply across long-lifecycle programs.
Supply support for BZX79-C18,143 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, industrial, and consumer markets.
The BZX79 series belongs to Nexperia's legacy Zener diode product line, engineered for cost-sensitive, low-power voltage regulation and reference applications where ±2% or ±5% tolerance meets system requirements.
FAQ
What is the maximum continuous reverse current the BZX79-C18,143 can sustain at 25 °C?
The BZX79-C18,143 has no defined maximum continuous reverse current limit - it is rated by power dissipation. At 25 °C ambient, Ptot = 500 mW implies IZ ≤ 27.8 mA (500 mW ÷ 18 V), assuming full voltage drop across the diode. Derating applies above 50 °C ambient per Rth j-a = 380 K/W.
Does the BZX79-C18,143 have a specified forward voltage, and how is it used in design?
Yes: VF ≤ 0.9 V at IF = 10 mA. This parameter matters only when the diode is forward-biased - for example, in polarity protection circuits or dual-diode clamp configurations. In normal Zener operation (reverse bias), forward voltage is irrelevant to regulation performance.
How does the temperature coefficient affect long-term stability in a 18 V reference circuit?
With +12.4 mV/K typical tempco, the BZX79-C18,143 drifts +124 mV over a 10 °C rise. For a 12-bit ADC with 18 V full scale, this equals ~4 LSB drift. System-level calibration or complementary tempco components (e.g., NTC thermistors) may be needed for sub-0.1% stability over industrial temperature ranges.
Can the BZX79-C18,143 replace the BZX79-B18 in an existing design?
Yes, but with trade-offs: the BZX79-C18 has ±5% tolerance (17.6–18.4 V) versus BZX79-B18's ±2% (17.6–18.4 V overlaps, but B18 tighter at 17.64–18.36 V). Differential resistance is higher (225 Ω vs. 200 Ω typ), increasing load regulation error. Use C18 only if ±5% initial accuracy suffices and thermal design accommodates higher rdif heating.
BZX79-C18,143 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-C18,143 FAQ
1.How can I place an order for BZX79-C18,143 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79-C18,143 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-C18,143 reliable?
The price and inventory of BZX79-C18,143 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79-C18,143 is usually 5 days.
3.What payment methods are accepted for BZX79-C18,143?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79-C18,143 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79-C18,143?
BZX79-C18,143 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79-C18,143 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-C18,143?
For technical support, including BZX79-C18,143 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79-C18,143 requirements.
6.How does Aetrix verify that BZX79-C18,143 is sourced from the original manufacturer or authorized distributors?
All BZX79-C18,143 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-C18,143 meets industry standards.
7.What is the process for return or replacement of BZX79-C18,143?
All BZX79-C18,143 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79-C18,143, 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-C18,143 part is unused and in its original packaging.
Return procedure for BZX79-C18,143:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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