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Nexperia USA Inc. BZX38450-B18-QX
- Part No.:
- BZX38450-B18-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-76, SOD-323
- Datasheet:
-
BZX38450-B18-QX.pdf
- Description:
- DIODE ZENER 18V 300MW SOD323
- Quantity:
- Payment:
- Shipping:
Inventory:6,930
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Product details
Overview
BZX38450-B18-QX from Nexperia is a low-current Zener voltage regulator diode in SOD323 (SC-76) package, rated for 18 V nominal regulation at 50 µA test current, with ±2 % tolerance, 300 mW power dissipation, and AEC-Q101 qualification for automotive use.
For engineers reviewing the BZX38450-B18-QX datasheet, BZX38450-B18-QX pinout, BZX38450-B18-QX application, or BZX38450-B18-QX equivalent, this page delivers verified electrical characteristics, thermal behavior, cathode/anode terminal mapping, automotive-grade reliability data, and direct replacement guidance for low-bias voltage reference design.
Technical Context
This device operates as a two-terminal shunt voltage regulator, maintaining stable 18 V output across load variations using reverse-biased Zener breakdown. Its specified 50 µA test current enables ultra-low quiescent current operation ideal for battery-powered systems.
It exhibits a temperature coefficient of +12.4 mV/K and differential resistance of 225 Ω at 5 mA, supporting precision biasing in temperature-sensitive analog circuits. The intentional minor leakage rise improves switching speed and reduces noise per AN90031.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 18 V at IZ = 50 µA - defines regulation point for low-current bias networks |
| Tolerance | ±2 % - ensures tight voltage accuracy without post-production trimming |
| Power Dissipation | 300 mW at Tamb ≤ 25 °C - supports continuous operation on standard FR4 PCB without heatsinking |
| Differential Resistance | 225 Ω at IZ = 5 mA - determines regulation stiffness under dynamic load changes |
| Forward Voltage | 0.9 V at IF = 10 mA - enables predictable forward conduction during transient overvoltage events |
| Junction Temperature | 150 °C maximum - allows operation in under-hood automotive environments |
| AEC-Q101 Qualified | Yes - validated for automotive electronics per stress test requirements for discrete semiconductors |
Pinout & Package
SOD323 (SC-76) surface-mount plastic package: 1.7 mm × 1.25 mm × 0.95 mm body, 1.3 mm lead pitch, cathode marked by bar on top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Connected to regulated output node; marking bar identifies this terminal |
| 2 | Anode (A) | Connected to ground or lower-potential rail; completes Zener bias path |
Key Features
| Feature | Design Value |
|---|---|
| Low test current operation | Specified at 50 µA - minimizes standby current in portable and energy-harvesting systems |
| Optimized leakage profile | Intentional minor IR rise per AN90031 - enhances switching response and reduces broadband noise |
| Automotive qualification | AEC-Q101 compliant - certified for engine control units, body electronics, and ADAS sensor interfaces |
| Thermal performance | Rth(j-a) = 415 K/W - enables reliable operation on single-sided FR4 PCBs without thermal vias |
| Small footprint | SOD323 package - saves board space in dense automotive and IoT PCB layouts |
Applications
| Automotive Body Control Module (BCM) | Portable Medical Sensor Biasing |
|---|---|
Use Scenario: Providing stable 18 V reference for microcontroller ADC input scaling and CAN transceiver bias in door module electronics. IC Role / Device Role / Timing Role: Shunt voltage regulator establishing precise analog reference voltage independent of supply rail fluctuations. Use Value: Enables consistent sensor measurement accuracy across battery voltage range (9–16 V) while meeting AEC-Q101 reliability requirements. |
Use Scenario: Supplying low-power bias voltage to MEMS pressure sensor front-end amplifier in handheld diagnostic devices. IC Role / Device Role / Timing Role: Low-quiescent Zener reference ensuring <1 µA total standby current draw from coin-cell battery. Use Value: Extends battery life beyond 2 years in intermittent-use clinical instruments without compromising signal integrity. |
| Industrial PLC Input Protection | Smart Home Smoke Detector Reference |
Use Scenario: Clamping and regulating 18 V auxiliary rail for optocoupler isolation drivers in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Overvoltage protection and voltage stabilization element in 24 V DC input stage. Use Value: Prevents false triggering during ESD transients while maintaining regulation within ±2 % over –40 °C to +125 °C ambient. |
Use Scenario: Generating stable 18 V reference for electrochemical CO sensor bias circuit in battery-operated residential smoke alarms. IC Role / Device Role / Timing Role: Precision voltage source enabling repeatable gas concentration calibration across production batches. Use Value: Reduces field calibration drift to <0.5 %/year by minimizing temperature-induced reference shift via +12.4 mV/K coefficient matching. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX384-C18-Q | ±5 % tolerance, higher leakage at low voltage, same SOD323 package | Acceptable where cost sensitivity outweighs voltage accuracy requirements | Select for non-critical biasing in consumer-grade lighting controls or AC-DC auxiliary rails |
| MMSZ5245B-TP | ±5 % tolerance, 500 mW rating, SOD-123 package, no AEC-Q101 qualification | Larger footprint, higher power handling, not automotive-qualified | Choose when higher surge capability is needed and automotive compliance is not required |
Compared with BZX38450-B18-QX, the BZX384-C18-Q trades voltage accuracy for cost in identical packaging, while MMSZ5245B-TP offers greater power margin but lacks automotive qualification and occupies more PCB area.
Availability
BZX38450-B18-QX is available at Aetrix Electronics and suitable for automotive body electronics, portable medical sensors, industrial PLC input stages, and smart home safety devices requiring stable component supply with guaranteed long-term continuity.
Supply support for BZX38450-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 high-volume, high-reliability essential components including logic, discretes, MOSFETs, and bipolar transistors.
The BZX38450-Q series belongs to Nexperia's automotive-qualified Zener diode product line, engineered specifically for low-current, high-stability voltage reference and protection in harsh-environment electronic control units.
FAQ
What is the maximum reverse voltage this diode can withstand before breakdown?
The BZX38450-B18-QX has a nominal Zener voltage of 18 V with ±2 % tolerance, meaning its guaranteed breakdown range is 17.64 V to 18.36 V at 50 µA test current. It is not rated for sustained operation above its specified VZ; exceeding this risks thermal runaway due to its 300 mW power limit.
Does this part require a series resistor in typical Zener regulator configurations?
Yes - a series current-limiting resistor is mandatory to set the operating current within the 50 µA to 250 mA range. For 18 V regulation from a 24 V supply, a 330 Ω resistor establishes ~18 mA bias, balancing regulation stability against power dissipation in the diode and resistor.
How does the AEC-Q101 qualification impact its use in non-automotive designs?
AEC-Q101 qualification confirms extended temperature operation (–55 °C to +150 °C), robustness against mechanical stress, and lifetime reliability under accelerated aging tests. These attributes directly benefit industrial, medical, and aerospace applications demanding proven field reliability beyond commercial-grade components.
Can this diode be used in parallel for higher current capability?
No - Zener diodes exhibit manufacturing variation in VZ, causing current hogging if paralleled. Even matched units risk thermal instability due to positive temperature coefficient above ~5 V. For higher current, use a single higher-rated Zener or a dedicated shunt regulator IC.
BZX38450-B18-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX38450-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 @ 13.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-323
BZX38450-B18-QX FAQ
1.How can I place an order for BZX38450-B18-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX38450-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 BZX38450-B18-QX reliable?
The price and inventory of BZX38450-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 BZX38450-B18-QX is usually 5 days.
3.What payment methods are accepted for BZX38450-B18-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX38450-B18-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX38450-B18-QX?
BZX38450-B18-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX38450-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 BZX38450-B18-QX?
For technical support, including BZX38450-B18-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX38450-B18-QX requirements.
6.How does Aetrix verify that BZX38450-B18-QX is sourced from the original manufacturer or authorized distributors?
All BZX38450-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 BZX38450-B18-QX meets industry standards.
7.What is the process for return or replacement of BZX38450-B18-QX?
All BZX38450-B18-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX38450-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 BZX38450-B18-QX part is unused and in its original packaging.
Return procedure for BZX38450-B18-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX38450-B18-QX Tags
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