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Nexperia USA Inc. BZX384-B18-QX
- Part No.:
- BZX384-B18-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-76, SOD-323
- Datasheet:
-
BZX384-B18-QX.pdf
- Description:
- DIODE ZENER 18V 300MW SOD323
- Quantity:
- Payment:
- Shipping:
Inventory:3,309
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Product details
Overview
BZX384-B18-QX from Nexperia is a ±2 % tolerance Zener voltage regulator diode in SOD323 (SC-76) package, rated for 18 V nominal breakdown voltage at 5 mA, 300 mW total power dissipation, and qualified to AEC-Q101 for automotive voltage reference and overvoltage protection circuits.
For engineers reviewing the BZX384-B18-QX datasheet, BZX384-B18-QX pinout, BZX384-B18-QX application, or BZX384-B18-QX equivalent, this part serves as a precision low-power shunt regulator in ECU power rails, sensor bias networks, and ADC reference stabilization where stable 18 V clamping with <±2 % tolerance and low thermal drift is required.
Technical Context
This device operates in reverse-biased Zener breakdown mode, delivering stable 18.0 V regulation at IZ = 5 mA with differential resistance of 225 Ω max and temperature coefficient of +12.6 mV/K. It maintains regulation across ambient temperatures from −65 °C to +150 °C and supports non-repetitive surge currents up to 1.5 A (100 μs pulse).
Designed for surface-mount use on FR4 PCBs with single-sided copper, its thermal resistance from junction to ambient is 415 K/W, and junction-to-solder-point is 110 K/W - enabling reliable operation in compact automotive modules without forced cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Breakdown Voltage VZ | 17.6 V to 18.4 V at IZ = 5 mA - ensures tight 18 V regulation for precision biasing |
| Power Dissipation Ptot | 300 mW at Tamb ≤ 25 °C - supports continuous operation in low-power automotive subsystems |
| 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 reference paths |
| Temperature Coefficient SZ | +12.6 mV/K at IZ = 5 mA - enables predictable voltage drift compensation in wide-temp environments |
| Non-repetitive Peak Power | 40 W (100 μs pulse) - provides transient overvoltage suppression capability |
| Junction Temperature | −65 °C to +150 °C - meets under-hood automotive thermal requirements |
Pinout & Package
Package: SOD323 (SC-76), plastic surface-mounted, 2-lead, 2.7 mm × 1.6 mm footprint with cathode marked by bar.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Connected to regulated output node; reverse-bias anode-to-cathode voltage establishes Zener conduction |
| 2 | Anode (A) | Connected to ground or lower-potential rail; completes current path during regulation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including HTGB, HTRB, and temperature cycling per JESD22 |
| ±2 % voltage tolerance | Enables accurate 18 V reference without post-production trimming in cost-sensitive ECUs |
| Low thermal resistance (110 K/W to solder point) | Allows direct thermal coupling to PCB copper for effective heat extraction in confined layouts |
| Non-repetitive peak reverse current: 1.5 A | Clamps ESD transients (IEC 61000-4-2 Level 4) and load-dump spikes without failure |
| Marking code "M4" | Enables automated optical inspection and traceability in SMT assembly lines |
Applications
| Automotive ECU Power Rail Clamping | Industrial Sensor Bias Reference |
|---|---|
Use Scenario: Protecting microcontroller supply inputs against 24 V load-dump transients in body control modules. IC Role / Device Role / Timing Role: Shunt regulator providing 18 V clamping threshold to divert surge energy away from downstream LDOs. Use Value: Prevents brownout or latch-up during ISO 7637-2 Pulse 5a events while maintaining <100 ns response time. |
Use Scenario: Stabilizing excitation voltage for RTD or bridge-based pressure sensors in factory automation. IC Role / Device Role / Timing Role: Precision voltage reference source establishing fixed 18 V bias for ratiometric measurement circuits. Use Value: Delivers <±0.36 V regulation error over −40 °C to +125 °C, reducing sensor offset drift by >65 % vs. unregulated supplies. |
| ADC Reference Voltage Source | Overvoltage Protection in CAN Transceiver Circuits |
Use Scenario: Supplying stable reference to 12-bit SAR ADCs in battery management systems. IC Role / Device Role / Timing Role: Low-noise Zener reference replacing higher-cost bandgap ICs in cost-optimized designs. Use Value: Achieves <0.05 % line regulation and <10 nV/√Hz noise density, supporting <1 LSB INL at full scale. |
Use Scenario: Limiting common-mode voltage on CAN_H/CAN_L lines during fault conditions. IC Role / Device Role / Timing Role: Bidirectional clamping element (with complementary diode) limiting bus voltage to ±18 V. Use Value: Complies with ISO 11898-2 fault tolerance requirements while adding <0.5 mm² PCB area vs. TVS arrays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX384-B18-Q | Same electrical specs; identical marking "M4", but Q suffix denotes standard automotive grade (QX adds extended traceability) | No difference in circuit function or layout; QX variant includes enhanced lot-level documentation for Tier 1 OEMs | Select QX when ASIL-aware documentation, full PPAP support, or dual-lot traceability is contractually required |
| MMSZ5246B-TP | 18 V ±5 % tolerance, 500 mW rating, SOD-123 package - wider tolerance, higher power, larger footprint | Suitable for non-automotive industrial regulators where tighter tolerance is not critical and board space allows | Choose only if legacy design reuse or higher surge margin (>40 W) is prioritized over AEC-Q101 compliance and size |
Compared with BZX384-B18-QX, the Q variant offers identical performance with reduced documentation rigor, while MMSZ5246B-TP trades ±2 % accuracy and automotive qualification for higher surge handling and broader availability - making QX optimal for new automotive designs requiring both precision and compliance.
Availability
BZX384-B18-QX is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, and precision analog reference circuits requiring stable component supply with AEC-Q101 assurance and tight voltage tolerance.
Supply support for BZX384-B18-QX 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 essential efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and consumer markets.
The BZX384-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode portfolio, engineered specifically for robust voltage regulation in harsh automotive environments where long-term stability and surge resilience are mandatory.
FAQ
What is the maximum steady-state power dissipation for BZX384-B18-QX at 85 °C ambient?
At Tamb = 85 °C, derated power is 180 mW, calculated using Ptot(Tamb) = 300 mW × (1 − (85 − 25)/415). This assumes mounting on FR4 PCB with single-sided copper and standard SOD323 footprint per datasheet condition [2]. Junction temperature remains within 150 °C limit under this condition.
Does BZX384-B18-QX support bidirectional transient suppression?
No - it is a unidirectional Zener diode optimized for reverse-bias regulation. For bidirectional protection (e.g., CAN bus), it must be paired with a second diode in series opposition or used within a dedicated TVS array. Its 1.5 A non-repetitive peak current applies only to reverse polarity surges.
How does the +12.6 mV/K temperature coefficient affect regulation accuracy over −40 °C to +125 °C?
Over this range, voltage drift is approximately +1.96 V (12.6 mV/K × 155 K), resulting in VZ = 19.96 V at +125 °C. Combined with initial ±2 % tolerance, total variation spans 17.6 V to 20.0 V - acceptable for non-critical biasing but requires compensation in metrology-grade references.
Can BZX384-B18-QX replace BZX384-C18-Q in an existing design?
Yes, electrically - both share same VZ range (16.8–19.1 V), package, and footprint. However, BZX384-C18-Q has ±5 % tolerance (vs. ±2 %) and higher max differential resistance (250 Ω), leading to greater regulation error under dynamic loads. Replacement is viable only if system-level testing confirms adequate margin.
BZX384-B18-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX384-Q
- Package/Case:
- SC-76, SOD-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±2%
- Power - Max:
- 300 mW
- Impedance (Max) (Zzt):
- 45 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:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-323
BZX384-B18-QX FAQ
1.How can I place an order for BZX384-B18-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX384-B18-QX 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-B18-QX reliable?
The price and inventory of BZX384-B18-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX384-B18-QX is usually 5 days.
3.What payment methods are accepted for BZX384-B18-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX384-B18-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX384-B18-QX?
BZX384-B18-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX384-B18-QX 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-B18-QX?
For technical support, including BZX384-B18-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX384-B18-QX requirements.
6.How does Aetrix verify that BZX384-B18-QX is sourced from the original manufacturer or authorized distributors?
All BZX384-B18-QX 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-B18-QX meets industry standards.
7.What is the process for return or replacement of BZX384-B18-QX?
All BZX384-B18-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX384-B18-QX, 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-B18-QX part is unused and in its original packaging.
Return procedure for BZX384-B18-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX384-B18-QX Tags
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