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Nexperia USA Inc. BZX84W-B3V9-QX
- Part No.:
- BZX84W-B3V9-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-70, SOT-323
- Datasheet:
-
BZX84W-B3V9-QX.pdf
- Description:
- DIODE ZENER 3.9V 275MW SOT323
- Quantity:
- Payment:
- Shipping:
Inventory:7,174
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Product details
Overview
BZX84W-B3V9-QX from Nexperia is a ±2 % tolerance Zener diode in SOT323 (SC-70) package, rated for 3.9 V nominal regulation voltage at 5 mA, with 275 mW total power dissipation and 3 µA reverse current at VR = 1 V. It is AEC-Q101 qualified and designed for precision voltage reference and overvoltage protection in automotive power rails and sensor interface circuits.
For engineers reviewing the BZX84W-B3V9-QX datasheet, BZX84W-B3V9-QX pinout, BZX84W-B3V9-QX application, or BZX84W-B3V9-QX equivalent, this page delivers verified Zener parameters including differential resistance (90 Ω), temperature coefficient (−2.5 mV/K), junction-to-ambient thermal resistance (455 K/W), and non-repetitive surge capability (40 W).
Technical Context
This device operates as a two-terminal shunt voltage regulator, maintaining stable output by conducting reverse current above its specified Zener breakdown voltage of 3.82–3.98 V. Its low 90 Ω differential resistance ensures minimal voltage deviation under load variation, while the negative −2.5 mV/K temperature coefficient stabilizes regulation across ambient ranges from −55 °C to +150 °C.
Designed for surface-mount use on FR4 PCBs with single-sided copper, it leverages the SOT323 footprint for high-density placement and supports reflow/wave soldering per JEDEC J-STD-020/001. The "n.c." terminal (Pin 2) is internally unconnected and must remain floating in circuit layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.82–3.98 V at IZ = 5 mA; defines precise regulation threshold for 3.3 V rail clamping and reference generation |
| Tolerance | ±2 % (B-series); enables tighter feedback loop control vs. ±5 % C-series variants |
| Differential Resistance (rdif) | 90 Ω max at IZ = 5 mA; limits output voltage shift to ≤0.45 V under ±5 mA load change |
| Reverse Current (IR) | 3 µA max at VR = 1 V; ensures low leakage in standby mode for battery-sensitive systems |
| Total Power Dissipation (Ptot) | 275 mW at Tamb = 25 °C on standard FR4; sets maximum continuous Zener current to ~70 mA |
| Thermal Resistance (Rth(j-a)) | 455 K/W; implies ~125 °C junction rise at full 275 mW dissipation, requiring derating above 70 °C ambient |
| Non-repetitive Surge (PZSM) | 40 W for tp ≤ 100 µs; supports transient suppression of ESD or load-dump spikes without failure |
Pinout & Package
SOT323 (SC-70) plastic surface-mounted package with 3 leads; leadless construction optimized for automated assembly and high board density. Dimensions: 2.2 × 1.35 × 0.95 mm (L × W × H), 0.65 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A) | Anode | Forward-biased terminal; connected to lower-potential node during regulation (e.g., GND or return path) |
| 2 (n.c.) | Not Connected | Internally unconnected; must be left floating-no trace or pad connection permitted |
| 3 (K) | Cathode | Zener breakdown terminal; connected to regulated voltage node (e.g., 3.3 V rail or IC VREF input) |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including HTOL, TC, and ESD testing-enables use in engine control units and ADAS sensors |
| Low differential resistance | 90 Ω max ensures <1% output drift across 5–10 mA operating range, critical for ADC reference stability |
| Negative temperature coefficient | −2.5 mV/K compensates for positive TC of other components (e.g., op-amps), improving system-level thermal drift performance |
| High-frequency response | Diode capacitance ≤6 pF at 1 MHz enables effective noise filtering up to ~100 MHz in RF bias networks |
| Small-footprint SOT323 | 0.65 mm pitch and 2.2 mm length allow placement adjacent to ICs without routing congestion in space-constrained modules |
Applications
| Automotive Sensor Biasing | 3.3 V Rail Overvoltage Clamp |
|---|---|
|
Use Scenario: Providing stable bias voltage to analog pressure or temperature sensors in engine bay modules exposed to 12 V supply transients. IC Role / Device Role / Timing Role: Shunt regulator establishing fixed 3.9 V reference for sensor excitation and signal conditioning amplifier inputs. Use Value: ±2 % tolerance and −2.5 mV/K TC maintain sensor output accuracy within ±0.5 % over −40 °C to +125 °C, meeting ISO 16750-2 pulse test requirements. |
Use Scenario: Protecting 3.3 V microcontroller I/O pins from load-dump surges exceeding 24 V in body control modules. IC Role / Device Role / Timing Role: Fast-acting clamp diverting transient energy to ground before voltage exceeds 4.5 V. Use Value: 40 W non-repetitive surge rating absorbs 100 µs pulses up to 10 A without degradation, eliminating need for external TVS diodes. |
| ADC Reference Stabilization | Low-Power IoT Node Regulation |
|
Use Scenario: Supplying clean reference voltage to 12-bit SAR ADCs in industrial data loggers powered by Li-ion batteries. IC Role / Device Role / Timing Role: Precision Zener generating 3.9 V reference independent of battery voltage decay (2.8–4.2 V range). Use Value: 3 µA reverse leakage at 1 V ensures <1 µA quiescent draw in sleep mode, extending 10-year battery life targets. |
Use Scenario: Regulating supply to BLE SoCs and environmental sensors in compact wireless sensor nodes. IC Role / Device Role / Timing Role: Compact voltage reference enabling direct 3.3 V rail derivation from 5 V USB or boost converter outputs. Use Value: SOT323 footprint (2.2 × 1.35 mm) saves >40 % board area vs. DO-35 packages, critical for sub-10 cm² PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84W-C3V9-Q | ±5 % tolerance (3.7–4.1 V range) vs. ±2 %; identical package, power, and thermal specs | Acceptable where system-level calibration compensates for wider VZ spread; not suitable for closed-loop feedback | Select when cost sensitivity outweighs regulation precision; same footprint and assembly process |
| MMSZ4685T1G | 3.9 V nominal, ±5 %, SOD-123 package (3.7 × 1.6 mm); 500 mW Ptot, higher 100 Ω rdif | Higher power handling but larger footprint and looser tolerance; less stable under dynamic loads | Choose only if board layout allows SOD-123 and thermal margin exceeds 275 mW requirement |
Compared with BZX84W-C3V9-Q, the BZX84W-B3V9-QX offers tighter regulation for feedback-critical designs; versus MMSZ4685T1G, it trades power headroom for superior precision and space efficiency in automotive and portable electronics.
Availability
BZX84W-B3V9-QX is available at Aetrix Electronics and suitable for automotive sensor modules, industrial ADC reference circuits, low-power IoT nodes, and 3.3 V rail protection requiring stable component supply across extended temperature and lifecycle demands.
Supply support for BZX84W-B3V9-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 discrete and logic devices, with leadership in automotive-qualified components and advanced packaging.
The BZX84W-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode product line, engineered specifically for robust voltage reference and transient suppression in harsh automotive and industrial environments.
FAQ
What is the maximum continuous Zener current for BZX84W-B3V9-QX at 85 °C ambient?
At 85 °C ambient, the 275 mW total power dissipation must be derated using Rth(j-a) = 455 K/W. Junction temperature rise is limited to 150 °C, allowing 65 K rise above ambient. Maximum allowable power is 65 K ÷ 455 K/W ≈ 143 mW. At 3.9 V, this corresponds to ~36.7 mA continuous Zener current.
Can Pin 2 (n.c.) be grounded or tied to a signal trace?
No-Pin 2 is internally unconnected and must remain electrically floating. Connecting it to ground, power, or any signal violates the device's internal construction and may cause unpredictable leakage, thermal instability, or premature failure. Layout guidelines require no copper trace or solder mask opening at this pad.
How does the −2.5 mV/K temperature coefficient affect regulation accuracy over −40 °C to +125 °C?
Over this 165 K range, the coefficient causes a total drift of −2.5 mV/K × 165 K = −413 mV. With nominal VZ = 3.9 V, this represents a −10.6 % shift. However, the ±2 % initial tolerance dominates error budget; actual worst-case regulation remains within 3.82 V to 3.98 V ±0.413 V, i.e., 3.41–4.39 V.
Is BZX84W-B3V9-QX suitable for replacing a 3.3 V Zener in an existing design?
No-it is a 3.9 V Zener and will not regulate at 3.3 V. For 3.3 V operation, use BZX84W-B3V3-Q (3.23–3.37 V) or BZX84W-C3V3-Q (3.10–3.50 V). Substituting BZX84W-B3V9-QX would raise regulated voltage by ~0.6 V, potentially damaging downstream 3.3 V logic or analog components.
BZX84W-B3V9-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):
- 3.9 V
- Tolerance:
- ±2.05%
- Power - Max:
- 275 mW
- Impedance (Max) (Zzt):
- 90 Ohms
- Current - Reverse Leakage @ Vr:
- 3 µA @ 1 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-B3V9-QX FAQ
1.How can I place an order for BZX84W-B3V9-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84W-B3V9-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-B3V9-QX reliable?
The price and inventory of BZX84W-B3V9-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-B3V9-QX is usually 5 days.
3.What payment methods are accepted for BZX84W-B3V9-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84W-B3V9-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84W-B3V9-QX?
BZX84W-B3V9-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84W-B3V9-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-B3V9-QX?
For technical support, including BZX84W-B3V9-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84W-B3V9-QX requirements.
6.How does Aetrix verify that BZX84W-B3V9-QX is sourced from the original manufacturer or authorized distributors?
All BZX84W-B3V9-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-B3V9-QX meets industry standards.
7.What is the process for return or replacement of BZX84W-B3V9-QX?
All BZX84W-B3V9-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX84W-B3V9-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-B3V9-QX part is unused and in its original packaging.
Return procedure for BZX84W-B3V9-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84W-B3V9-QX Tags
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