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Nexperia USA Inc. BZX384-A18X
- Part No.:
- BZX384-A18X
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-76, SOD-323
- Datasheet:
-
BZX384-A18X.pdf
- Description:
- DIODE ZENER 18V 300MW SOD323
- Quantity:
- Payment:
- Shipping:
Inventory:2,448
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Product details
Overview
BZX384-A18X from Nexperia is a ±1 % tolerance Zener voltage regulator diode in SOD323 (SC-76) package, rated for 18 V nominal breakdown at 5 mA, with 300 mW total power dissipation and 225 Ω maximum differential resistance. It provides precision voltage reference and overvoltage protection in low-power analog circuits, including sensor biasing and power supply feedback loops.
For engineers reviewing the BZX384-A18X datasheet, BZX384-A18X pinout, BZX384-A18X application, or BZX384-A18X equivalent, key selection criteria include its 18 V Zener voltage with ±1 % tolerance, 225 Ω dynamic impedance at IZ = 5 mA, -65 °C to +150 °C operating temperature range, and suitability for space-constrained PCB layouts requiring stable low-current regulation.
Technical Context
This device operates as a reverse-biased silicon Zener diode, maintaining a stable 18 V reference across its terminals when reverse current exceeds the knee region (IZ ≥ 1 mA). Its temperature coefficient of +12.6 mV/K at IZ = 5 mA enables predictable drift compensation in temperature-sensitive designs.
The SOD323 package delivers low thermal resistance (Rth(j-a) = 415 K/W in free air), while non-repetitive peak reverse power dissipation reaches 40 W for 100 μs pulses - supporting transient suppression in low-energy surge events without thermal runaway.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.82 V to 18.18 V at IZ = 5 mA - ensures ±1 % accuracy for precision reference applications |
| Differential Resistance (rdif) | ≤225 Ω at IZ = 5 mA - minimizes output voltage variation under load current changes |
| Reverse Current (IR) | ≤0.05 μA at VR = 14.4 V - guarantees low leakage in high-impedance bias networks |
| Power Dissipation (Ptot) | 300 mW at Tamb ≤ 25 °C - defines continuous DC power handling on standard FR4 PCB |
| Peak Pulse Power (PZSM) | 40 W for tp = 100 μs - supports ESD/inductive spike clamping without failure |
| Junction Temperature (Tj) | −65 °C to +150 °C - enables operation in extended industrial environments |
| Forward Voltage (VF) | 0.9 V at IF = 10 mA - allows use as low-drop rectifier or clamp in forward mode |
Pinout & Package
Package: SOD323 (SC-76), surface-mount plastic case with 2 leads, 1.35 mm × 0.85 mm footprint, cathode marked by bar on top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Connected to regulated output node; reverse-bias voltage applied here relative to anode |
| 2 | Anode (A) | Connected to ground or lower-potential rail; completes Zener conduction path |
Key Features
| Feature | Design Value |
|---|---|
| ±1 % Zener voltage tolerance | Enables direct replacement in 18 V reference designs without recalibration or resistor trimming |
| Low dynamic impedance (225 Ω) | Reduces output voltage shift under ±1 mA load variation, improving regulation stability |
| SOD323 ultra-small footprint | Occupies <1.2 mm² PCB area - ideal for wearables, IoT sensors, and dense power management modules |
| 150 °C max junction temperature | Supports reliable operation in sealed enclosures or near heat-generating components |
| Non-repetitive 40 W pulse rating | Clamps short-duration transients (e.g., relay coil flyback, ESD) without degradation |
Applications
| Industrial Sensor Signal Conditioning | USB-C Power Delivery Feedback |
|---|---|
Use Scenario: Biasing op-amp input stages and ADC reference dividers in factory-floor temperature/humidity transmitters. IC Role / Device Role / Timing Role: Provides stable 18 V reference for ratiometric scaling of analog sensor outputs. Use Value: ±1 % VZ tolerance eliminates need for post-calibration trim resistors, reducing BOM count and test time. |
Use Scenario: Setting precise feedback threshold in USB-C PD sink controller voltage monitoring circuitry. IC Role / Device Role / Timing Role: Acts as shunt reference in optocoupler-coupled feedback loop for isolated 18 V auxiliary rail. Use Value: 225 Ω rdif ensures <10 mV error across 0–5 mA feedback current range, meeting USB PD v3.1 ripple requirements. |
| Automotive Body Control Module (Non-Safety) | Medical Portable Diagnostic Device |
Use Scenario: Regulating 18 V supply for LIN bus transceivers and LED drivers in door module PCBs. IC Role / Device Role / Timing Role: Shunt regulator stabilizing local 18 V rail derived from switched 24 V vehicle battery. Use Value: −65 °C to +150 °C Tj range supports under-hood mounting without derating below 300 mW. |
Use Scenario: Generating clean 18 V bias for photodiode transimpedance amplifiers in handheld pulse oximeters. IC Role / Device Role / Timing Role: Low-noise voltage reference suppressing supply-induced AC coupling into sensitive analog front-end. Use Value: 0.05 μA IR at 14.4 V prevents loading of high-impedance photodiode nodes, preserving SNR >85 dB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ON Semiconductor MMBZ5245BS | 18 V ±5 % tolerance, 200 mW Ptot, SOT-23 package (larger than SOD323) | Higher tolerance and lower power limit reduce accuracy in precision references | Select only if cost sensitivity outweighs regulation accuracy and board space constraints |
| Vishay BZX384-B18 | Same SOD323 package but ±2 % tolerance and 250 Ω rdif at IZ = 5 mA | Looser tolerance increases calibration burden in metrology-grade instruments | Acceptable for non-critical biasing where 18 V ±0.36 V drift is permissible |
Compared with BZX384-A18X, MMBZ5245BS trades accuracy and size for lower unit cost, while BZX384-B18 retains identical form factor but sacrifices 1 % tolerance and 25 Ω lower impedance - making the A-grade optimal for high-stability, space-limited designs.
Availability
BZX384-A18X is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery feedback, automotive body control modules, and medical portable diagnostic devices requiring stable component supply and long-term obsolescence management.
Supply support for BZX384-A18X 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 semiconductor expert focused on high-volume, high-reliability logic, discrete, and MOSFET solutions, headquartered in Nijmegen, Netherlands.
The BZX384 series belongs to Nexperia's precision Zener diode product line, engineered specifically for low-power voltage reference and overvoltage protection in space-constrained consumer, industrial, and computing applications.
FAQ
What is the maximum continuous reverse current for BZX384-A18X at 25 °C ambient?
The device has no specified maximum continuous reverse current; instead, it is limited by power dissipation. At Tamb = 25 °C, Ptot = 300 mW implies Imax ≈ 16.7 mA (300 mW ÷ 18 V), assuming full Zener voltage drop. Derating is required above 25 °C per Rth(j-a) = 415 K/W.
Can BZX384-A18X be used in series to achieve higher reference voltages?
Yes - two BZX384-A18X diodes in series yield ~36 V with ±2 % combined tolerance (root-sum-square of individual tolerances). However, thermal tracking between devices must be ensured via adjacent placement and shared copper pour to avoid mismatched temperature coefficients.
Does the marking code '37' on BZX384-A18X indicate anything beyond part identification?
Yes - '37' is the standardized Nexperia marking for BZX384-A18X, defined in Table 4 of the datasheet. It uniquely identifies the ±1 % 18 V variant within the BZX384-A family and is laser-etched on the cathode-side surface of the SOD323 package.
How does the +12.6 mV/K temperature coefficient affect long-term stability in a 50 °C ambient environment?
From 25 °C to 50 °C ΔT = +25 K, resulting in +315 mV (12.6 mV/K × 25 K) VZ shift - approximately +1.75 % of nominal 18 V. This drift is linear and predictable, enabling software-based compensation in closed-loop systems using onboard temperature sensing.
BZX384-A18X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX384
- Package/Case:
- SC-76, SOD-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±1%
- Power - Max:
- 300 mW
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 12.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 100 mA
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-323
BZX384-A18X FAQ
1.How can I place an order for BZX384-A18X through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX384-A18X 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 BZX384-A18X reliable?
The price and inventory of BZX384-A18X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX384-A18X is usually 5 days.
3.What payment methods are accepted for BZX384-A18X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX384-A18X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX384-A18X?
BZX384-A18X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX384-A18X 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 BZX384-A18X?
For technical support, including BZX384-A18X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX384-A18X requirements.
6.How does Aetrix verify that BZX384-A18X is sourced from the original manufacturer or authorized distributors?
All BZX384-A18X 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 BZX384-A18X meets industry standards.
7.What is the process for return or replacement of BZX384-A18X?
All BZX384-A18X units undergo pre-shipment inspection (PSI). If there is an issue with BZX384-A18X, 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 BZX384-A18X part is unused and in its original packaging.
Return procedure for BZX384-A18X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX384-A18X Tags
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