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Nexperia USA Inc. BZX38450-B33X
- Part No.:
- BZX38450-B33X
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-76, SOD-323
- Datasheet:
-
BZX38450-B33X.pdf
- Description:
- DIODE ZENER 33V 300MW SOD323
- Quantity:
- Payment:
- Shipping:
Inventory:7,496
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Product details
Overview
BZX38450-B33X from Nexperia is a low-current Zener voltage regulator diode in SOD323 (SC-76) package, designed for precision biasing and voltage reference in ultra-low-power circuits. It delivers a nominal 33 V regulation at 50 µA test current, with ±2 % tolerance, 300 mW total power dissipation, and 32.3–33.7 V working voltage range at Tj = 25 °C - ideal for battery-powered sensor nodes and portable instrumentation.
For engineers reviewing the BZX38450-B33X datasheet, BZX38450-B33X pinout, BZX38450-B33X application, or BZX38450-B33X equivalent, key selection criteria include its low 50 µA regulation current, tight ±2 % tolerance, SOD323 footprint compatibility, thermal resistance of 415 K/W (junction-to-ambient), and intentional leakage optimization for noise-sensitive analog front-ends.
Technical Context
This Zener diode operates in reverse breakdown mode with a specified 33 V nominal working voltage at IZ = 50 µA, exhibiting differential resistance of 325 Ω at IZ = 5 mA and temperature coefficient of +0.05 mV/K. Its low test current enables stable regulation in micro-power systems where supply current is constrained.
The device features optimized leakage behavior per AN90031 to reduce switching noise and improve transient response in signal conditioning paths. Thermal performance is characterized with Rth(j-a) = 415 K/W on FR4 PCB and Rth(j-sp) = 110 K/W to cathode solder point, supporting reliable operation up to 150 °C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal VZ | 33 V at IZ = 50 µA - defines primary regulation point for low-bias reference design |
| VZ Range | 32.3 V to 33.7 V - ensures ±2 % tolerance compliance across production lot |
| Differential Resistance | 325 Ω at IZ = 5 mA - determines output impedance and load regulation sensitivity |
| Forward Voltage | ≤ 0.9 V at IF = 10 mA - limits conduction loss during forward bias or ESD clamp operation |
| Total Power Dissipation | 300 mW at Tamb ≤ 25 °C - sets maximum continuous DC power handling on standard FR4 PCB |
| Junction Temperature | −55 °C to +150 °C - supports industrial and extended-temperature embedded applications |
| Package | SOD323 (SC-76) - 1.7 mm × 1.25 mm × 0.95 mm surface-mount footprint with 1.3 mm lead pitch |
Pinout & Package
SOD323 (SC-76) plastic surface-mount package with two leads: anode (A) and cathode (K). The marking bar on the device body identifies the cathode terminal. Mounting uses standard reflow or wave soldering footprints defined in Figures 10 and 11 of the datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Connected to regulated output node; polarity marker aligns with PCB silkscreen bar |
| 2 | Anode (A) | Connected to ground or lower-potential rail; forms reverse-biased junction for Zener operation |
Key Features
| Feature | Design Value |
|---|---|
| Low test current regulation | Specified at 50 µA - enables use in nanoampere-bias circuits without compromising accuracy |
| Tight voltage tolerance | ±2 % (B-series) - reduces need for post-calibration in precision reference designs |
| Optimized leakage profile | Intentional minor rise per AN90031 - suppresses switching transients and improves SNR in analog signal chains |
| Thermal robustness | Rth(j-a) = 415 K/W - allows operation up to 150 °C junction temperature on minimal copper area |
| Small-footprint packaging | SOD323 (1.7 × 1.25 mm) - saves board space in compact IoT sensors and wearables |
Applications
| Portable Battery Monitor | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Monitoring Li-ion cell voltage in handheld diagnostic tools with 3.3 V MCU and no dedicated LDO. IC Role / Device Role / Timing Role: Zener reference diode providing stable 33 V reference for ADC input scaling and overvoltage detection threshold. Use Value: Enables accurate 12-bit voltage measurement down to 10 µA quiescent current, extending battery life beyond 12 months. |
Use Scenario: Biasing op-amp input stages in 4–20 mA loop-powered pressure transmitters. IC Role / Device Role / Timing Role: Low-leakage voltage reference establishing precise offset and gain-setting points in analog front-end. Use Value: Reduces zero-drift error by 40 % versus generic Zeners due to optimized leakage behavior per AN90031. |
| Medical Pulse Oximeter Front-End | Smart Meter Reference Subsystem |
Use Scenario: Providing stable bias for photodiode transimpedance amplifiers in battery-operated pulse oximeters. IC Role / Device Role / Timing Role: Low-noise Zener reference setting common-mode voltage and gain stability under varying ambient temperature. Use Value: Maintains <±0.5 % reference drift across −20 °C to +70 °C, meeting ISO 80601 clinical accuracy requirements. |
Use Scenario: Generating calibration reference for metrology-grade energy measurement ICs in Class 0.2 smart meters. IC Role / Device Role / Timing Role: Precision shunt reference supplying stable 33 V to sigma-delta ADC reference buffer. Use Value: Achieves <10 ppm/°C TC with matched layout, enabling sub-0.1 % energy billing accuracy over 10-year field life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX384-C33 | ±5 % tolerance, higher leakage at low VR, 31.35–34.65 V range | Suitable for non-critical biasing where cost > precision | Select when ±5 % regulation tolerance is acceptable and leakage sensitivity is low |
| MMSZ5257B | Same 33 V nominal, SOD-123 package (2.7 × 1.6 mm), 500 mW Ptot, higher rdiff (700 Ω) | Requires larger PCB area; better for higher-power analog rails | Choose when thermal margin > board space constraints and higher power headroom is needed |
Compared with BZX38450-B33X, BZX384-C33 trades precision for cost in non-critical biasing, while MMSZ5257B offers higher power handling at the expense of footprint size and dynamic impedance - making the B33X optimal for space-constrained, low-noise, ±2 % reference designs.
Availability
BZX38450-B33X is available at Aetrix Electronics and suitable for portable medical devices, industrial sensor modules, smart meter reference subsystems, and battery-powered instrumentation requiring stable component supply with traceable sourcing and long-lifecycle support.
Supply support for BZX38450-B33X 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 delivering high-performance, reliable discrete, logic, and MOSFET solutions with focus on efficiency, miniaturization, and sustainability.
The BZX38450 series belongs to Nexperia's precision low-current Zener portfolio, engineered specifically for ultra-low-power voltage reference and biasing in battery-operated and noise-sensitive analog systems.
FAQ
What is the minimum reverse current required to achieve rated 33 V regulation?
The BZX38450-B33X is specified at IZ = 50 µA for nominal 33 V regulation, with VZ guaranteed between 32.3 V and 33.7 V at this current. Operation below 50 µA results in progressively lower VZ; datasheet Figure 7 confirms regulation remains usable down to ~10 µA, though with increased deviation.
Can BZX38450-B33X be used in series for higher-voltage references?
Yes - multiple BZX38450-B33X diodes may be stacked in series to generate higher reference voltages (e.g., 66 V with two units), provided current uniformity is maintained via series ballast resistors and thermal coupling is minimized to avoid mismatched temperature coefficients.
How does the "intentional minor rise of leakage current" affect circuit noise?
Per AN90031, the controlled leakage increase reduces high-frequency switching noise and improves transient response in analog signal paths by stabilizing junction capacitance and minimizing avalanche mode instability - verified in low-noise op-amp biasing applications.
Is the SOD323 package compatible with standard reflow profiles?
Yes - the SOD323 package is qualified for IPC/JEDEC J-STD-020D reflow, with peak temperature up to 260 °C. Figure 10 provides the recommended reflow solder land pattern (0.5 mm pad width, 1.15 mm length, 1.35 mm center-to-center pitch) for reliable assembly.
BZX38450-B33X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX38450
- Package/Case:
- SC-76, SOD-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±2%
- Power - Max:
- 300 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 25 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-323
BZX38450-B33X FAQ
1.How can I place an order for BZX38450-B33X through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX38450-B33X 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-B33X reliable?
The price and inventory of BZX38450-B33X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX38450-B33X is usually 5 days.
3.What payment methods are accepted for BZX38450-B33X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX38450-B33X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX38450-B33X?
BZX38450-B33X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX38450-B33X 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-B33X?
For technical support, including BZX38450-B33X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX38450-B33X requirements.
6.How does Aetrix verify that BZX38450-B33X is sourced from the original manufacturer or authorized distributors?
All BZX38450-B33X 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-B33X meets industry standards.
7.What is the process for return or replacement of BZX38450-B33X?
All BZX38450-B33X units undergo pre-shipment inspection (PSI). If there is an issue with BZX38450-B33X, 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-B33X part is unused and in its original packaging.
Return procedure for BZX38450-B33X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX38450-B33X Tags
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MMBZ5240B-7-F
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
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BZT52C15S-7-F
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MM5Z5V1ST1G
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SMAZ12-13-F
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