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Nexperia USA Inc. BZX79-B18,143
- Part No.:
- BZX79-B18,143
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79-B18,143.pdf
- Description:
- DIODE ZENER 18V 400MW ALF2
- Quantity:
- Payment:
- Shipping:
Inventory:4,990
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Product details
Overview
BZX79-B18,143 from Nexperia is a ±2% tolerance Zener voltage regulator diode with nominal 18 V breakdown voltage at 5 mA test current, 50 Ω typical differential resistance, and −65 °C to +200 °C junction temperature range. It operates as a low-power voltage reference in bias networks, overvoltage clamping circuits, and analog signal conditioning stages within industrial sensor interfaces and power supply feedback loops.
For engineers reviewing the BZX79-B18,143 datasheet, BZX79-B18,143 pinout, BZX79-B18,143 application, or BZX79-B18,143 equivalent, key selection criteria include its 18 V nominal Zener voltage, ±2% tolerance, 500 mW total power dissipation at Tamb = 50 °C, 50 Ω typical dynamic impedance, and DO-35 (SOD27) hermetically sealed glass package - all critical for precision voltage referencing in space-constrained, thermally stable designs.
Technical Context
This discrete Zener diode functions exclusively in reverse-bias breakdown mode, delivering stable DC reference voltage under controlled current conditions. Its operation relies on controlled avalanche and Zener mechanisms depending on voltage level, with thermal coefficient of +12.4 mV/K at IZ = 5 mA ensuring predictable drift behavior across temperature.
The device exhibits non-repetitive peak reverse power dissipation of 40 W for 100 μs pulses and reverse leakage current ≤50 nA at VR = 0.7 × VZnom, enabling reliable transient suppression and low-quiescent-current biasing in battery-powered systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage (VZ) | 18 V at IZ = 5 mA - defines precise DC reference point for feedback or clamping |
| Tolerance | ±2% - ensures tight voltage accuracy without post-production trimming |
| Differential Resistance (rdif) | 50 Ω typical at IZ = 5 mA - determines output impedance and load regulation sensitivity |
| Total Power Dissipation (Ptot) | 500 mW at Tamb = 50 °C - sets maximum continuous thermal load on PCB layout |
| Reverse Leakage Current (IR) | ≤50 nA at VR = 12.6 V (0.7 × VZnom) - enables ultra-low standby current in always-on circuits |
| Thermal Resistance (Rth j-a) | 380 K/W - defines junction-to-ambient temperature rise per watt under standard mounting |
| Package | SOD27 (DO-35) - axial-leaded, hermetically sealed glass package for high reliability and moisture resistance |
Pinout & Package
Hermetically sealed glass SOD27 (DO-35) package with axial leads; cathode identified by black band. Lead length ≤8 mm; no metallization pad required on PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / reverse-bias reference ground node | Connected to lower-potential side of Zener circuit; establishes reference return path |
| Cathode | Zener breakdown terminal / regulated output node | Marked with black band; delivers stable 18 V when reverse-biased above breakdown threshold |
Key Features
| Feature | Design Value |
|---|---|
| ±2% voltage tolerance | Enables direct replacement in precision reference designs without calibration adjustment |
| 500 mW power rating at 50 °C ambient | Supports robust operation in enclosed industrial enclosures without forced cooling |
| Non-repetitive 40 W surge capability | Provides transient overvoltage protection up to 100 μs without degradation |
| −65 °C to +200 °C operating junction range | Validates use in automotive engine compartments and industrial motor drive environments |
| Low 50 nA leakage at 0.7×VZ | Minimizes quiescent current draw in battery-backed real-time clock and memory backup circuits |
Applications
| Industrial Sensor Signal Conditioning | Switch-Mode Power Supply Feedback |
|---|---|
|
Use Scenario: Stabilizing reference voltage for bridge sensor amplifiers in pressure transmitters. IC Role / Device Role / Timing Role: Zener diode provides fixed 18 V reference for op-amp biasing and ADC reference scaling. Use Value: ±2% tolerance and 50 Ω dynamic impedance ensure <0.5% gain error across temperature in 4–20 mA loop transmitters. |
Use Scenario: Setting output voltage threshold in flyback converter feedback network. IC Role / Device Role / Timing Role: Acts as precision shunt reference in optocoupler-coupled feedback path. Use Value: 18 V breakdown enables 24 V output regulation with minimal component count and stable loop response. |
| Automotive Body Control Module Clamping | IoT Node Battery Backup Reference |
|
Use Scenario: Protecting microcontroller GPIO pins from load-dump transients in 12 V vehicle systems. IC Role / Device Role / Timing Role: Shunt clamp absorbing energy during ISO 7637-2 pulse 5a events. Use Value: 40 W non-repetitive surge rating handles 100 μs spikes up to 300 V without failure. |
Use Scenario: Providing stable voltage reference for RTC and SRAM retention during main power loss. IC Role / Device Role / Timing Role: Low-leakage Zener maintains accurate timekeeping reference from coin cell. Use Value: ≤50 nA reverse current at 12.6 V extends CR2032 battery life beyond 10 years in sleep mode. |
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% tolerance, 1 Ω higher rdif (51 Ω), same DO-41 package | Lower accuracy limits use in precision feedback; higher thermal resistance (400 K/W) | Select only where cost sensitivity outweighs voltage stability requirements |
| BZX84-C18 | 18 V, ±5% tolerance, SOT-23 surface-mount package, 250 mW Ptot | Not suitable for through-hole legacy designs; limited surge capability (1 W) | Choose for space-constrained PCBs where reflow compatibility and density are prioritized |
Compared with BZX79-B18,143, the 1N4746A trades tighter thermal performance for looser voltage tolerance, while the BZX84-C18 sacrifices surge robustness and power handling for miniaturization - making the BZX79-B18,143 optimal for through-hole, high-reliability, medium-power reference applications.
Availability
BZX79-B18,143 is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body control modules, switch-mode power supply feedback networks, and IoT node battery backup circuits requiring stable component supply across extended product lifecycles.
Supply support for BZX79-B18,143 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, with focus on automotive, industrial, and consumer electronics reliability.
The BZX79 series belongs to Nexperia's legacy Zener diode portfolio designed specifically for low-power voltage regulation and reference applications in cost-sensitive, high-volume industrial and automotive systems.
FAQ
What is the maximum continuous power dissipation for BZX79-B18,143 at 70 °C ambient?
At Tamb = 70 °C, the maximum continuous power dissipation is derated to 300 mW based on Rth j-a = 380 K/W and Tj max = 200 °C. This requires thermal design margin below 200 °C junction temperature to prevent permanent degradation.
Can BZX79-B18,143 be used in surface-mount designs?
No - BZX79-B18,143 uses the axial-leaded SOD27 (DO-35) through-hole package and is not compatible with SMT assembly. For surface-mount equivalents, consider the BZX84-C18 in SOT-23 or MMBZ5245B in SOT-23.
What is the Zener test current specified for voltage measurement?
The nominal 18 V Zener voltage is measured at IZtest = 5 mA, as defined in Table 1 of the datasheet. This current level balances measurement repeatability with self-heating effects and is the standard condition for tolerance verification.
How does temperature affect the 18 V Zener voltage?
The temperature coefficient is +12.4 mV/K at IZ = 5 mA, meaning the Zener voltage increases by approximately 12.4 mV per Kelvin rise in junction temperature - a positive drift characteristic typical of mid-voltage Zeners above 5.6 V.
BZX79-B18,143 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:
- ±2%
- 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-B18,143 FAQ
1.How can I place an order for BZX79-B18,143 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79-B18,143 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-B18,143 reliable?
The price and inventory of BZX79-B18,143 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79-B18,143 is usually 5 days.
3.What payment methods are accepted for BZX79-B18,143?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79-B18,143 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79-B18,143?
BZX79-B18,143 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79-B18,143 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-B18,143?
For technical support, including BZX79-B18,143 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79-B18,143 requirements.
6.How does Aetrix verify that BZX79-B18,143 is sourced from the original manufacturer or authorized distributors?
All BZX79-B18,143 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-B18,143 meets industry standards.
7.What is the process for return or replacement of BZX79-B18,143?
All BZX79-B18,143 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79-B18,143, 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-B18,143 part is unused and in its original packaging.
Return procedure for BZX79-B18,143:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX79-B18,143 Tags
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