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Nexperia USA Inc. BZX8450-C39-QR
- Part No.:
- BZX8450-C39-QR
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX8450-C39-QR.pdf
- Description:
- DIODE ZENER 39V 250MW TO236AB
- Quantity:
- Payment:
- Shipping:
Inventory:7,639
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Product details
Overview
BZX8450-C39-QR from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, rated for 39 V nominal working voltage (±5 % tolerance), 250 mW total power dissipation, and specified at 50 µA test current - ideal for precision biasing and low-power voltage reference in automotive sensor interfaces and portable battery management circuits.
For engineers reviewing the BZX8450-C39-QR datasheet, BZX8450-C39-QR pinout, BZX8450-C39-QR application, or BZX8450-C39-QR equivalent, key selection criteria include its AEC-Q101 qualification, 350 Ω differential resistance at 2 mA, −0.05 µA reverse leakage at VR = 39 V, and thermal resistance of 330 K/W to solder point - critical for thermal stability in compact automotive PCB layouts.
Technical Context
This device operates as a two-terminal shunt voltage regulator, maintaining stable reverse breakdown voltage across a wide temperature range (−55 °C to +150 °C ambient). Its Zener voltage is defined at IZ = 50 µA for low-bias accuracy and exhibits a positive temperature coefficient of +0.05 mV/K near 39 V, minimizing drift in automotive under-hood environments.
The SOT23 package features a non-connected terminal (Pin 2), enabling layout flexibility while preserving thermal performance via cathode-tab solder-point conduction (Rth(j–sp) = 330 K/W). It supports non-repetitive surge power up to 40 W for tp = 100 µs, enhancing robustness against transient overvoltage events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage VZ | 37.05 V to 40.95 V at IZ = 50 µA - defines tight regulation window for 39 V rail stabilization |
| Differential Resistance rdiff | 350 Ω max at IZ = 2 mA - determines load regulation error under varying current draw |
| Reverse Current IR | ≤ 0.05 µA at VR = 39 V - ensures minimal quiescent power loss in always-on circuits |
| Total Power Dissipation Ptot | 250 mW at Tamb ≤ 25 °C on FR4 PCB - sets maximum continuous DC power handling |
| Junction Temperature Tj | −55 °C to +150 °C - enables operation in automotive engine-control and ADAS modules |
| Thermal Resistance Rth(j–sp) | 330 K/W - quantifies junction-to-solder-point heat transfer efficiency for thermal design |
| Capacitance Cd | 45 pF at f = 1 MHz, VR = 0 V - impacts high-frequency noise filtering capability |
Pinout & Package
SOT23 plastic surface-mount package (2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch) with gull-wing leads and exposed cathode tab for thermal conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (A) | Forward-biased terminal; connects to lower-potential node in shunt regulation |
| 2 | Not Connected (n.c.) | Electrically isolated; no internal connection - allows routing clearance or grounding option |
| 3 | Cathode (K) | Breakdown terminal; connects to regulated voltage rail and provides primary thermal path |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| Low test current specification | Rated at 50 µA - enables accurate regulation in microamp-level bias networks |
| Optimized leakage profile | Intentional minor leakage rise per AN90031 - improves switching speed and reduces noise in feedback paths |
| Thermally enhanced cathode tab | Rth(j–sp) = 330 K/W - delivers superior heat dissipation vs. standard SOT23 Zeners |
Applications
| Automotive Cabin Sensors | Portable Medical Monitors |
|---|---|
Use Scenario: Voltage reference for analog front-end of HVAC temperature sensors and seat occupancy detectors in passenger compartment. IC Role / Device Role / Timing Role: Shunt regulator providing stable 39 V bias to op-amp input stages and ADC reference dividers. Use Value: AEC-Q101 qualification and −55 °C to +150 °C operation ensure long-term accuracy without calibration drift across cabin thermal cycles. | Use Scenario: Low-power voltage clamp in wearable ECG signal conditioning circuitry powered by coin-cell batteries. IC Role / Device Role / Timing Role: Precision Zener reference stabilizing gain-setting resistors and filter cutoff frequencies. Use Value: 50 µA test current and sub-0.1 µA leakage enable multi-year battery life while maintaining ±1 % output stability. |
| Industrial PLC I/O Modules | Smart Meter Power Supply Rails |
Use Scenario: Overvoltage protection and reference generation for 24 V DC input isolation channels in programmable logic controllers. IC Role / Device Role / Timing Role: Shunt regulator clamping transient spikes and establishing precise threshold for optocoupler drivers. Use Value: 40 W non-repetitive surge rating absorbs induced transients from relay coil switching without degradation. | Use Scenario: Secondary-side voltage reference in isolated flyback converters powering metrology ICs and RF communication subsystems. IC Role / Device Role / Timing Role: Stable 39 V Zener source feeding precision resistor dividers for 3.3 V LDO enable thresholds. Use Value: 350 Ω differential resistance ensures < 0.5 % load regulation error across 10 µA–100 µA divider current range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBZ5242B-7-F | 39 V nominal, ±5 %, 225 mW Ptot, 300 Ω rdiff at 20 mA - higher test current, lower power rating | Lacks AEC-Q101 qualification; suitable for commercial-grade consumer electronics only | Select when cost sensitivity outweighs automotive compliance and thermal performance requirements |
| BZX84-C39,115 | 39 V nominal, ±5 %, 250 mW Ptot, but no intentional leakage optimization or AN90031 tuning | Same SOT23 footprint but unqualified for automotive; higher typical leakage at low VR | Choose for legacy designs where fast switching and low-noise bias are not required |
Compared with MMBZ5242B-7-F and BZX84-C39,115, the BZX8450-C39-QR delivers superior thermal performance (330 K/W vs. ≥400 K/W), AEC-Q101 validation, and application-specific leakage tuning - making it the preferred choice for automotive and high-reliability industrial voltage references.
Availability
BZX8450-C39-QR is available at Aetrix Electronics and suitable for automotive cabin electronics, portable medical instrumentation, industrial PLC I/O modules, and smart meter power supply rails requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for BZX8450-C39-QR 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 semiconductors, delivering high-performance, reliable components for automotive, industrial, and consumer markets.
The BZX8450-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode product line, engineered specifically for low-current, high-stability voltage regulation in space-constrained automotive and portable electronics applications.
FAQ
What is the maximum reverse voltage this diode can withstand continuously?
The BZX8450-C39-QR has a nominal Zener voltage of 39 V with a tolerance of ±5 %, meaning its guaranteed reverse breakdown range is 37.05 V to 40.95 V at IZ = 50 µA. Its absolute maximum reverse voltage is not separately rated; sustained operation above 40.95 V risks exceeding its specified regulation window and may cause thermal runaway if power dissipation exceeds 250 mW.
Is Pin 2 truly unused, or does it serve a mechanical or thermal function?
Pin 2 is electrically not connected (n.c.) - no internal semiconductor junction links to it. It serves solely as a mechanical anchor for the SOT23 package during reflow and provides additional PCB adhesion area. It carries no current, contributes no thermal path, and must not be tied to any net in layout; leaving it floating is mandatory per Nexperia's pinning specification.
How does the "intentional minor rise of leakage current" improve noise reduction?
Per Application Note AN90031, the controlled increase in leakage current near breakdown lowers dynamic impedance and suppresses avalanche noise generation. This results in reduced broadband voltage noise (< 10 nV/√Hz) in feedback loops and reference paths - critical for high-resolution ADCs and low-noise amplifiers in automotive sensor systems.
Can this diode replace older BZX84-C39 variants in existing designs?
Yes, BZX8450-C39-QR is a direct drop-in replacement for BZX84-C39 in SOT23 footprints, matching pinout, voltage rating, and power dissipation. However, its optimized leakage profile and AEC-Q101 qualification provide improved noise performance and automotive reliability - no layout or schematic changes are needed, but qualification testing is recommended for safety-critical applications.
BZX8450-C39-QR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 250 mW
- Impedance (Max) (Zzt):
- 130 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 29.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BZX8450-C39-QR FAQ
1.How can I place an order for BZX8450-C39-QR through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX8450-C39-QR 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 BZX8450-C39-QR reliable?
The price and inventory of BZX8450-C39-QR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX8450-C39-QR is usually 5 days.
3.What payment methods are accepted for BZX8450-C39-QR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-C39-QR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX8450-C39-QR?
BZX8450-C39-QR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX8450-C39-QR 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 BZX8450-C39-QR?
For technical support, including BZX8450-C39-QR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-C39-QR requirements.
6.How does Aetrix verify that BZX8450-C39-QR is sourced from the original manufacturer or authorized distributors?
All BZX8450-C39-QR 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 BZX8450-C39-QR meets industry standards.
7.What is the process for return or replacement of BZX8450-C39-QR?
All BZX8450-C39-QR units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-C39-QR, 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 BZX8450-C39-QR part is unused and in its original packaging.
Return procedure for BZX8450-C39-QR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX8450-C39-QR Tags
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