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Nexperia USA Inc. BZX84W-B39-QX
- Part No.:
- BZX84W-B39-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-70, SOT-323
- Datasheet:
-
BZX84W-B39-QX.pdf
- Description:
- DIODE ZENER 39V 275MW SOT323
- Quantity:
- Payment:
- Shipping:
Inventory:7,682
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Product details
Overview
BZX84W-B39-QX from Nexperia is a ±2% tolerance Zener voltage regulator diode with a nominal breakdown voltage of 39 V, designed for precision voltage reference and regulation in automotive-grade SMT circuits. It delivers 350 Ω differential resistance at 2 mA, operates up to 150 °C junction temperature, and is qualified to AEC-Q101 for under-hood power supply stabilization and ECU biasing.
For engineers reviewing the BZX84W-B39-QX datasheet, BZX84W-B39-QX pinout, BZX84W-B39-QX application, or BZX84W-B39-QX equivalent, key selection criteria include Zener voltage tolerance (±2%), thermal resistance (455 K/W), non-repetitive surge capability (130 A peak reverse current), and SC-70 package compatibility with high-frequency decoupling layouts.
Technical Context
This Zener diode functions as a two-terminal shunt voltage regulator, maintaining stable output voltage across variable load currents by operating in reverse breakdown. Its 39 V nominal Zener voltage is specified at IZ = 2 mA with a typical temperature coefficient of +36.4 mV/K, indicating positive drift with rising temperature.
The device uses silicon planar epitaxial construction in a leadless SOT323 (SC-70) package, enabling low parasitic capacitance (0.7 pF at 1 MHz, VR = 0 V) and fast transient response-critical for noise-sensitive analog references and automotive sensor signal conditioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 39 V nominal at IZ = 2 mA; tight ±2% tolerance ensures predictable clamping in safety-critical voltage monitoring. |
| Differential Resistance (rdiff) | 350 Ω max at IZ = 2 mA; defines regulation stiffness-lower values improve load regulation linearity. |
| Reverse Current (IR) | 50 nA max at VR = 27.3 V (0.7 × VZ); enables ultra-low standby leakage in always-on automotive modules. |
| Total Power Dissipation (Ptot) | 275 mW at Tamb = 25 °C on FR4 PCB; sets continuous DC regulation limit without forced cooling. |
| Non-repetitive Peak Reverse Current (IZSM) | 130 A at tp = 100 µs; supports transient overvoltage suppression in CAN/LIN bus protection stages. |
| Junction Temperature (Tj) | −55 °C to +150 °C operating range; validated for engine control unit (ECU) and transmission control module (TCM) environments. |
| Thermal Resistance (Rth(j-a)) | 455 K/W in free air on standard FR4; determines self-heating rise per watt-critical for derating in sealed enclosures. |
Pinout & Package
Package: SOT323 (SC-70), 3-lead leadless surface-mount plastic package with 0.65 mm pitch; dimensions 2.2 mm × 1.35 mm × 0.95 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (A) | Forward-biased terminal; connects to lower-potential node in shunt regulation configuration. |
| 2 | Not Connected (n.c.) | Internally isolated; must remain unconnected on PCB to avoid parasitic coupling or mechanical stress. |
| 3 | Cathode (K) | Reverse-biased terminal; ties to regulated voltage rail and current-limiting resistor in standard Zener topology. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive applications including powertrain and body electronics per stress test requirements. |
| ±2% Zener voltage tolerance | Enables tighter system-level voltage margining than ±5% variants-reducing need for post-regulation trimming. |
| Low 0.7 pF junction capacitance | Minimizes high-frequency signal distortion in RF bias networks and clock buffer references. |
| 150 °C maximum junction temperature | Supports operation adjacent to heat-generating power MOSFETs or microcontrollers in compact ECUs. |
| SC-70 footprint compatibility | Matches industry-standard reflow soldering profiles and automated optical inspection (AOI) fiducial alignment. |
Applications
| Engine Control Unit (ECU) Reference | Automotive Sensor Biasing |
|---|---|
Use Scenario: Providing stable 39 V reference for analog-to-digital converter (ADC) input scaling in gasoline direct injection (GDI) control modules. IC Role / Device Role / Timing Role: Shunt voltage regulator establishing precise upper rail for op-amp level-shifting circuitry feeding MCU ADC inputs. Use Value: ±2% tolerance and +36.4 mV/K TC ensure <±1.5% total error over −40 °C to +125 °C ambient, meeting ASIL-B functional safety calibration requirements. | Use Scenario: Biasing piezoresistive pressure sensors in brake-by-wire hydraulic control units. IC Role / Device Role / Timing Role: Low-noise Zener source supplying constant excitation voltage to Wheatstone bridge elements. Use Value: 0.7 pF capacitance prevents RF coupling into millivolt-level sensor outputs, preserving 16-bit measurement resolution. |
| CAN Transceiver Protection | Infotainment Power Sequencing |
Use Scenario: Clamping transients on CAN_H/CAN_L lines during load dump events in vehicle communication gateways. IC Role / Device Role / Timing Role: Fast-response shunt clamp absorbing 130 A surge pulses (100 µs) without failure per ISO 7637-2 Pulse 5a. Use Value: Non-repetitive peak reverse current rating directly satisfies automotive surge immunity compliance thresholds without external TVS cascading. | Use Scenario: Enabling controlled power-up sequencing of display driver ICs and audio amplifiers in head unit mainboards. IC Role / Device Role / Timing Role: Voltage supervisor element triggering enable signals when 39 V auxiliary rail reaches regulation threshold. Use Value: Tight 39 V ±2% tolerance eliminates need for external comparator hysteresis, reducing BOM count and layout area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84W-C39-Q | ±5% Zener voltage tolerance (37–41 V vs. 38.2–39.8 V) | Acceptable where system-level calibration compensates for wider voltage spread | Select for cost-sensitive body control modules where absolute accuracy is secondary to robustness. |
| MMSZ4702T1G | 39 V ±5%, SOD-123 package, 500 mW Ptot, higher Rth(j-a) (625 K/W) | Higher power handling but larger footprint and inferior thermal performance in dense layouts | Choose only when >275 mW continuous dissipation is required and board space permits larger package. |
Compared with BZX84W-C39-Q and MMSZ4702T1G, the BZX84W-B39-QX offers superior voltage accuracy and thermal efficiency in automotive SMT designs-making it optimal for ASIL-B reference paths and space-constrained ECU nodes where ±2% regulation and 455 K/W thermal resistance are decisive.
Availability
BZX84W-B39-QX is available at Aetrix Electronics and suitable for automotive power management, sensor interface design, and CAN bus protection requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for BZX84W-B39-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 BZX84W-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode product line, engineered specifically for automotive voltage regulation, reference, and transient suppression where precision, reliability, and small-footprint SMT integration are mandatory.
FAQ
What is the maximum continuous reverse current this Zener can handle at 39 V?
The BZX84W-B39-QX is rated for 275 mW total power dissipation at 25 °C ambient on a standard FR4 PCB. At its nominal 39 V Zener voltage, this corresponds to a maximum continuous reverse current of approximately 7.05 mA (275 mW ÷ 39 V). Derating applies above 25 °C per the 455 K/W thermal resistance.
Does this part have a built-in capacitor or require external filtering?
No, the BZX84W-B39-QX is a pure silicon Zener diode with no integrated capacitor. Its junction capacitance is 0.7 pF at 1 MHz and 0 V reverse bias-intentionally low for high-frequency stability. External RC filtering must be added separately if noise suppression beyond inherent diode characteristics is required.
Can Pin 2 (n.c.) be used as a heatsink pad or grounded for thermal improvement?
No-Pin 2 is internally not connected and must remain unconnected on the PCB. Routing traces to or soldering it to ground or a copper pour introduces mechanical stress, risk of shorting, and violates the qualified SOT323 footprint. Thermal performance relies solely on Pins 1 and 3 conduction paths and PCB copper area under the package body.
How does the +36.4 mV/K temperature coefficient affect regulation accuracy over temperature?
The +36.4 mV/K coefficient means the Zener voltage increases by ~36.4 mV per Kelvin rise in junction temperature. Over a 100 K range (−40 °C to +60 °C ambient, assuming moderate self-heating), this contributes ~3.6 V drift-offset by the ±2% initial tolerance. System-level calibration or compensation is required for sub-1% total accuracy across full automotive temperature range.
BZX84W-B39-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX84W-Q
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±2.05%
- Power - Max:
- 275 mW
- Impedance (Max) (Zzt):
- 130 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 27.3 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:
- SOT-323
BZX84W-B39-QX FAQ
1.How can I place an order for BZX84W-B39-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84W-B39-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 BZX84W-B39-QX reliable?
The price and inventory of BZX84W-B39-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84W-B39-QX is usually 5 days.
3.What payment methods are accepted for BZX84W-B39-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84W-B39-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84W-B39-QX?
BZX84W-B39-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84W-B39-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 BZX84W-B39-QX?
For technical support, including BZX84W-B39-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84W-B39-QX requirements.
6.How does Aetrix verify that BZX84W-B39-QX is sourced from the original manufacturer or authorized distributors?
All BZX84W-B39-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 BZX84W-B39-QX meets industry standards.
7.What is the process for return or replacement of BZX84W-B39-QX?
All BZX84W-B39-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX84W-B39-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 BZX84W-B39-QX part is unused and in its original packaging.
Return procedure for BZX84W-B39-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84W-B39-QX Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZT52C15-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
onsemi
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SMAJ4744A-TP
Micro Commercial Co
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BZT52C3V6LP-7
Diodes Incorporated
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SMAZ12-13-F
Diodes Incorporated
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