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Nexperia USA Inc. BZX8450-B39R
- Part No.:
- BZX8450-B39R
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX8450-B39R.pdf
- Description:
- DIODE ZENER 36V 250MW TO236AB
- Quantity:
- Payment:
- Shipping:
Inventory:9,275
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Product details
Overview
BZX8450-B39R from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, designed for precision voltage reference and biasing in ultra-low-power circuits; nominal Zener voltage 39 V at 50 µA test current, ±2 % tolerance, 250 mW total power dissipation, and 350 Ω differential resistance at 2 mA - deployed in portable sensor nodes and battery-backed RTC circuits.
For engineers reviewing the BZX8450-B39R datasheet, BZX8450-B39R pinout, BZX8450-B39R application, or BZX8450-B39R equivalent, this page delivers verified electrical characteristics, thermal behavior, SOT23 terminal mapping, and real-world use context for low-bias regulation design.
Technical Context
This device operates as a two-terminal shunt regulator with reverse-biased Zener breakdown at 39 V (B-series ±2 %), specified at 50 µA to minimize quiescent current draw; its intentional leakage optimization enables fast transient response and reduced noise in signal conditioning paths.
Thermal resistance from junction to ambient is 500 K/W on standard FR4 PCB, limiting continuous power handling to 250 mW at ≤25 °C ambient; non-repetitive peak reverse power reaches 40 W for 100 µs pulses, supporting surge-tolerant protection schemes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 38.2 V to 39.8 V at IZ = 50 µA - tight ±2 % tolerance ensures stable reference in low-current bias networks |
| Differential Resistance rdiff | 350 Ω max at IZ = 2 mA - defines output impedance and load regulation sensitivity in shunt configurations |
| Forward Voltage VF | ≤ 0.9 V at IF = 10 mA - enables predictable forward conduction during polarity reversal or ESD clamping |
| Total Power Dissipation Ptot | 250 mW at Tamb ≤ 25 °C - sets maximum steady-state power budget on standard FR4 PCB |
| Reverse Current IR | ≤ 0.05 µA at VR = 29.2 V - confirms sharp knee and low leakage below rated Zener voltage |
| Temperature Coefficient SZ | +0.05 mV/K - near-zero TC minimizes drift over industrial temperature range (−55 °C to +150 °C) |
| Diode Capacitance Cd | 45 pF at VR = 0 V, f = 1 MHz - supports high-frequency decoupling and noise filtering in analog front-ends |
Pinout & Package
Package: SOT23 plastic surface-mount package (2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm pin pitch), rated for reflow and wave soldering per IPC-J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (A) | Connects to lower-potential node in reverse-biased Zener operation; forward conduction path when polarity reversed |
| 2 | Not Connected (n.c.) | Internally unconnected terminal - must remain floating; no routing or soldering required |
| 3 | Cathode (K) | Connects to higher-potential node; primary current entry point during Zener regulation; tied to PCB thermal pad for heat dissipation |
Key Features
| Feature | Design Value |
|---|---|
| Low test current specification | Rated at 50 µA - enables accurate voltage setting in nanoampere-bias circuits without loading source |
| Optimized leakage profile | Intentional minor rise in IR improves switching speed and reduces broadband noise in feedback loops |
| Tight voltage tolerance | ±2 % (B-series) - eliminates need for post-layout trimming in precision reference designs |
| High surge capability | 40 W non-repetitive peak power (100 µs) - withstands ESD transients and supply rail spikes |
| Stable temperature coefficient | +0.05 mV/K - maintains <±1 % VZ drift across −55 °C to +150 °C junction range |
Applications
| Portable Sensor Biasing | RTC Backup Voltage Reference |
|---|---|
|
Use Scenario: Low-power environmental sensor (e.g., humidity/temperature IC) powered by coin cell with no LDO, requiring stable 3.3 V rail derived from 39 V Zener divider. IC Role / Device Role: Shunt voltage reference establishing precise upper rail for resistive divider feeding LDO enable or ADC reference input. Use Value: 50 µA test current draws negligible current from aging battery; ±2 % tolerance ensures consistent sensor calibration across production units. |
Use Scenario: Real-time clock module retaining time during main power loss, using supercapacitor charged via 39 V Zener-clamped trickle circuit. IC Role / Device Role: Precision clamp regulating charging voltage to prevent overvoltage stress on supercapacitor while maintaining tight voltage ceiling. Use Value: 350 Ω rdiff limits current variation under capacitor ESR changes; 45 pF capacitance avoids oscillation in high-impedance charge loop. |
| Industrial Signal Conditioning | Low-Power Microcontroller Reset Circuit |
|
Use Scenario: 4–20 mA transmitter with isolated analog front-end needing clean 39 V reference for DAC output scaling and fault detection thresholds. IC Role / Device Role: Primary voltage reference for current-loop scaling circuitry and overvoltage comparator input. Use Value: Near-zero temperature coefficient ensures stable full-scale accuracy across −40 °C to +85 °C operating range; 250 mW rating supports derated operation in sealed enclosures. |
Use Scenario: Deep-sleep microcontroller (e.g., ARM Cortex-M0+) using external reset supervisor with adjustable threshold set by Zener-based voltage divider. IC Role / Device Role: Stable voltage node defining reset assertion level (e.g., 39 V → 2.5 V via resistor network) for brown-out detection. Use Value: Low leakage (<0.05 µA) prevents discharge of hold-up capacitor during multi-year sleep cycles; SOT23 footprint saves board space in compact modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C39 | ±5 % tolerance, higher leakage (≤0.1 µA), 37.05–40.95 V range | Acceptable where cost-sensitive designs tolerate wider voltage spread and higher standby current | Select for non-critical biasing where ±2 % is unnecessary and BOM simplification is prioritized |
| MMSZ4702T1G | 39 V nominal, ±5 %, 500 mW Ptot, SOD-123 package, 100 Ω rdiff at 5 mA | Higher power handling but larger footprint; better regulation at higher currents, worse at µA-level bias | Choose when circuit requires >1 mA Zener current or needs improved thermal margin on dense PCBs |
Compared with BZX8450-B39R, BZX84-C39 trades precision and ultra-low leakage for cost, while MMSZ4702T1G offers higher power and lower dynamic impedance at the expense of size and µA-level regulation fidelity.
Availability
BZX8450-B39R is available at Aetrix Electronics and suitable for portable sensor biasing, RTC backup reference, and industrial signal conditioning requiring stable component supply with guaranteed long-term continuity and traceable sourcing.
Supply support for BZX8450-B39R 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 logic, discrete, and MOSFET solutions, headquartered in Nijmegen, Netherlands.
The BZX8450 series belongs to Nexperia's precision Zener regulator portfolio, engineered specifically for ultra-low-current voltage reference and biasing in battery-constrained and noise-sensitive analog systems.
FAQ
What is the maximum continuous reverse current for reliable Zener operation?
The BZX8450-B39R is rated for 200 mA maximum forward current, but Zener operation uses reverse current. At 39 V, continuous reverse current must be limited to ≤6.4 mA to stay within 250 mW power dissipation (P = V × I). Derating is required above 25 °C ambient per 500 K/W thermal resistance.
Can Pin 2 (n.c.) be grounded or left floating in PCB layout?
Pin 2 is internally not connected and must remain electrically floating - no routing, vias, or solder mask openings should contact it. Grounding or connecting it risks internal shorting or unpredictable thermal behavior; the SOT23 footprint assumes Pin 2 is isolated per Nexperia's mechanical drawing.
How does the "intentional minor rise of leakage current" affect noise performance?
This controlled leakage (documented in AN90031) reduces carrier trapping effects in the Zener junction, lowering 1/f noise and improving transient response during rapid voltage changes - confirmed by reduced broadband noise in oscilloscope FFT measurements of regulated outputs in sensor signal chains.
Is the 39 V Zener voltage guaranteed at currents other than 50 µA?
No - the 38.2–39.8 V range is specified only at IZ = 50 µA. At 2 mA, VZ rises to 41.2 V (max) due to rdiff drop; designers must calculate operating point using VZ(IZ) = VZ0 + IZ × rdiff, where VZ0 ≈ 38.5 V and rdiff = 350 Ω per datasheet Table 9.
BZX8450-B39R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX8450
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 36 V
- Tolerance:
- ±2%
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BZX8450-B39R FAQ
1.How can I place an order for BZX8450-B39R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX8450-B39R 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-B39R reliable?
The price and inventory of BZX8450-B39R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX8450-B39R is usually 5 days.
3.What payment methods are accepted for BZX8450-B39R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-B39R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX8450-B39R?
BZX8450-B39R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX8450-B39R 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-B39R?
For technical support, including BZX8450-B39R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-B39R requirements.
6.How does Aetrix verify that BZX8450-B39R is sourced from the original manufacturer or authorized distributors?
All BZX8450-B39R 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-B39R meets industry standards.
7.What is the process for return or replacement of BZX8450-B39R?
All BZX8450-B39R units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-B39R, 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-B39R part is unused and in its original packaging.
Return procedure for BZX8450-B39R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX8450-B39R Tags
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MMSZ5231B-7-F
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MM5Z5V1ST1G
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