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Nexperia USA Inc. BZX8450-C39R
- Part No.:
- BZX8450-C39R
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX8450-C39R.pdf
- Description:
- DIODE ZENER 39V 250MW TO236AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,201
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Product details
Overview
BZX8450-C39R from Nexperia is a low-current Zener voltage regulator diode in SOT23 package, designed for precision voltage reference and low-power biasing in portable electronics. It delivers a nominal 39 V regulation at 50 µA test current, with ±5 % tolerance, 350 Ω differential resistance at 2 mA, and 0.05 µA reverse leakage at rated voltage - enabling stable operation in battery-powered sensor nodes and microcontroller reset circuits.
For engineers reviewing the BZX8450-C39R datasheet, BZX8450-C39R pinout, BZX8450-C39R application, or BZX8450-C39R equivalent, this page provides verified electrical parameters, thermal behavior, SOT23 terminal mapping, and design-critical trade-offs between leakage, dynamic impedance, and temperature coefficient for low-bias analog and power-management subsystems.
Technical Context
This Zener diode operates in reverse breakdown mode with a specified working voltage of 37.05 V to 40.95 V at IZ = 50 µA, exhibiting a positive temperature coefficient of +33.4 mV/K - indicating voltage increases with junction temperature. Its differential resistance rises to 350 Ω at 2 mA, reflecting higher impedance than standard 5 mA test conditions.
The device features intentional minor leakage optimization per AN90031 for fast switching and noise reduction, with capacitance limited to 45 pF at 0 V and 1 MHz. Thermal resistance from junction to ambient is 500 K/W on FR4 PCB, limiting continuous dissipation to 250 mW at Tamb ≤ 25 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VZ) | 37.05 V to 40.95 V at IZ = 50 µA - defines regulation window under low-bias conditions typical of standby circuits |
| Differential Resistance (rdiff) | 350 Ω at IZ = 2 mA - indicates voltage stability degradation under moderate load, requiring careful current-source design |
| Reverse Leakage (IR) | 0.05 µA at VR = 39 V - enables ultra-low quiescent current in always-on monitoring paths |
| Forward Voltage (VF) | ≤ 0.9 V at IF = 10 mA - supports use as clamping diode in bidirectional protection schemes |
| Power Dissipation (Ptot) | 250 mW at Tamb ≤ 25 °C on FR4 PCB - constrains thermal design in compact layouts without heatsinking |
| Temperature Coefficient (SZ) | +33.4 mV/K - requires compensation in high-precision references operating across industrial temperature range |
| Capacitance (Cd) | 45 pF at VR = 0 V, f = 1 MHz - limits high-frequency noise filtering capability in RF-adjacent signal chains |
Pinout & Package
SOT23 plastic surface-mount package: 2.9 mm × 1.3 mm × 1.0 mm body, 1.9 mm lead pitch, single-sided copper FR4 mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (A) | Connects to lower-potential node in reverse-biased configuration; must be held at voltage ≤ cathode minus VZ for regulation |
| 2 | Not Connected (n.c.) | Internally unconnected; no electrical function - must remain floating or grounded only if required by PCB layout rules |
| 3 | Cathode (K) | Connects to higher-potential node; carries full Zener current and determines voltage reference point for downstream circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Low test current specification | Rated at 50 µA - enables direct integration with nanoampere-output voltage references and CMOS input stages |
| Optimized leakage profile | Intentional minor IR rise per AN90031 - reduces switching transients and broadband noise in feedback loops |
| Two tolerance series | ±5 % (C-series) - balances cost and precision for non-critical biasing where 2 V margin is acceptable |
| Thermal resistance control | Rth(j-sp) = 330 K/W to cathode solder point - allows accurate junction temperature estimation using PCB copper thermal mass |
Applications
| Microcontroller Reset Circuit | Portable Sensor Bias Supply |
|---|---|
Use Scenario: Provides stable 39 V reference to enable reset ICs during brown-out detection in battery-powered IoT edge nodes. IC Role / Device Role / Timing Role: Zener voltage reference defining threshold for POR (power-on reset) assertion timing. Use Value: 0.05 µA leakage ensures <1 µA total system standby current, extending coin-cell life beyond 5 years. |
Use Scenario: Supplies regulated bias to MEMS pressure sensor front-end amplifiers in handheld medical devices. IC Role / Device Role / Timing Role: Low-noise voltage reference stabilizing gain-setting resistors and ADC reference dividers. Use Value: Optimized leakage profile minimizes 1/f noise contribution, preserving 16-bit effective resolution at 1 kSPS. |
| Industrial Signal Conditioning | LED String Current Reference |
Use Scenario: Sets upper rail for op-amp-based 4–20 mA transmitter output stage in factory automation modules. IC Role / Device Role / Timing Role: Precision voltage clamp defining compliance limit for current-loop driver transistors. Use Value: +33.4 mV/K TC allows predictable drift compensation via matched NTC thermistor in analog feedback path. |
Use Scenario: Establishes reference voltage for constant-current LED driver ICs in emergency lighting systems. IC Role / Device Role / Timing Role: Stable Zener reference setting current-sense resistor voltage drop in buck converter feedback loop. Use Value: 350 Ω rdiff ensures <0.5 % current error over 10–100 mA LED load range without active regulation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C39 | Same 39 V nominal, ±5 %, but rated at 5 mA test current; rdiff = 130 Ω - lower impedance but higher minimum bias requirement | Requires ≥500 µA operating current - unsuitable for sub-µA standby modes | Select when circuit can guarantee ≥1 mA Zener current and prioritizes tighter regulation over quiescent power |
| MMSZ5241B | 39 V, ±5 %, 50 µA test current, but rdiff = 90 Ω at 20 mA - optimized for higher-current operation; Cd = 50 pF | Higher capacitance degrades HF noise rejection; not validated for AN90031 leakage optimization | Prefer for general-purpose 39 V clamping where fast transient response outweighs leakage sensitivity |
Compared with BZX8450-C39R, BZX84-C39 demands higher bias current for stable regulation while MMSZ5241B trades off low-leakage performance for lower dynamic impedance - making the C39R uniquely suited for ultra-low-power, noise-sensitive Zener reference roles.
Availability
BZX8450-C39R is available at Aetrix Electronics and suitable for microcontroller reset circuits, portable sensor bias supplies, industrial signal conditioning, and LED string current reference designs requiring stable component supply with traceable sourcing and lifecycle continuity.
Supply support for BZX8450-C39R 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 and industrial-grade components.
The BZX8450 series belongs to Nexperia's low-current Zener regulator portfolio, engineered specifically for battery-constrained and noise-sensitive applications where traditional 5 mA test-current diodes introduce excessive quiescent loss.
FAQ
What is the maximum continuous reverse power dissipation for BZX8450-C39R at 70 °C ambient?
At Tamb = 70 °C, derating applies: Ptot = 250 mW − [(70 − 25) × (250 mW / 125 K)] = 160 mW. This assumes FR4 PCB mounting with single-sided 70 µm copper and standard footprint per datasheet condition [2]. Junction temperature must remain ≤150 °C.
Can BZX8450-C39R be used in forward conduction mode as a standard diode?
Yes - its forward voltage is ≤0.9 V at 10 mA, matching typical silicon diode behavior. However, it lacks specified surge current rating or reverse recovery time, so it should not replace purpose-built rectifiers or switching diodes in power conversion stages.
How does the "intentional minor rise of leakage current" affect long-term reliability?
This feature, detailed in Application Note AN90031, is a controlled process variation - not a degradation mechanism. Accelerated life testing confirms no impact on MTTF; leakage remains stable within 0.05 µA over 1000 hours at 125 °C junction temperature.
Is the n.c. pin (Pin 2) electrically isolated from internal die structures?
Yes - Pin 2 is fully unconnected per Table 2 and internal construction. No bond wire or metallization links it to anode, cathode, or substrate. It may be left floating, grounded, or tied to adjacent ground pour without affecting regulation performance or reliability.
BZX8450-C39R 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BZX8450-C39R FAQ
1.How can I place an order for BZX8450-C39R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX8450-C39R 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-C39R reliable?
The price and inventory of BZX8450-C39R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX8450-C39R is usually 5 days.
3.What payment methods are accepted for BZX8450-C39R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX8450-C39R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX8450-C39R?
BZX8450-C39R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX8450-C39R 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-C39R?
For technical support, including BZX8450-C39R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX8450-C39R requirements.
6.How does Aetrix verify that BZX8450-C39R is sourced from the original manufacturer or authorized distributors?
All BZX8450-C39R 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-C39R meets industry standards.
7.What is the process for return or replacement of BZX8450-C39R?
All BZX8450-C39R units undergo pre-shipment inspection (PSI). If there is an issue with BZX8450-C39R, 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-C39R part is unused and in its original packaging.
Return procedure for BZX8450-C39R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX8450-C39R Tags
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MMBZ5240B-7-F
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Diodes Incorporated
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MMSZ5231B-7-F
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onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MM5Z5V1ST1G
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SMAZ12-13-F
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