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onsemi BZX84C39LT3G
- Part No.:
- BZX84C39LT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX84C39LT3G.pdf
- Description:
- DIODE ZENER 39V 250MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,392
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Product details
Overview
BZX84C39LT3G from onsemi is a 39 V ±5% standard-tolerance Zener diode in SOT-23 package, rated for 250 mW power dissipation on FR-5 board at 25°C, with 130 Ω dynamic impedance at 5 mA test current and 70 nA reverse leakage at 30.4 V, used for precision voltage reference and overvoltage protection in portable power rails.
For engineers reviewing the BZX84C39LT3G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage tolerance, thermal coefficient (27.3 mV/°C), junction capacitance (45 pF at 0 V), ESD robustness (Class 3, >16 kV HBM), and SOT-23 footprint compatibility for high-density PCB layouts.
Technical Context
This device operates as a two-terminal voltage regulator via controlled reverse breakdown, with specified Zener voltage measured under pulsed 5 mA test current (IZT) at 25°C ambient. Its temperature coefficient of +27.3 mV/°C indicates positive drift above 6 V, requiring thermal derating in enclosed environments.
The SOT-23 package features pin 1 (anode), pin 2 (no connection), and pin 3 (cathode), with cathode polarity marked by a band. It supports automated placement and reflow soldering up to 260°C for 10 seconds, and meets UL 94 V-0 flammability rating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage | 37–41 V at 5 mA test current - defines stable regulation range for 3.3 V/5 V rail clamping or reference generation |
| Power Dissipation | 250 mW on FR-5 board at 25°C - limits continuous current to ~6.4 mA at 39 V without heatsinking |
| Zener Impedance | 130 Ω at 5 mA - determines output voltage variation under load transients (e.g., ±0.83 V per ±6.4 mA change) |
| Reverse Leakage | 70 nA at 30.4 V - ensures minimal quiescent current in standby mode for battery-powered systems |
| Capacitance | 45 pF at 0 V, 1 MHz - impacts high-frequency noise filtering capability and signal integrity in RF-adjacent circuits |
| ESD Rating | Class 3 (>16 kV HBM) - enables direct integration into handheld interfaces without external protection |
| Thermal Coefficient | +27.3 mV/°C at 5 mA - requires thermal compensation in precision references operating across −55°C to +150°C |
Pinout & Package
SOT-23 (TO-236) surface-mount plastic package, 2.90 × 1.30 × 1.00 mm, void-free thermosetting case with corrosion-resistant finish, cathode indicated by band, UL 94 V-0 rated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential node; reverse-biased during regulation; must be routed with low-inductance path |
| 2 | No Connection | Internally unconnected; no PCB trace or pad required; must remain floating per datasheet |
| 3 | Cathode | Connected to regulated voltage node; polarity band identifies this terminal; critical for correct orientation in automated assembly |
Key Features
| Feature | Design Value |
|---|---|
| 250 mW FR-5 power rating | Enables compact voltage clamping in space-constrained mobile PCBs without thermal vias or copper pours |
| Class 3 ESD robustness | Eliminates need for discrete TVS diodes in USB, audio jack, or button interface protection circuits |
| Pb-free and RoHS compliant | Meets global environmental compliance requirements for consumer and industrial end products |
| Tight thermal resistance control | RJA = 500 °C/W enables predictable junction temperature rise in thermally isolated layouts |
| Standard tolerance (±5%) | Provides cost-optimized voltage reference for non-critical biasing and supply monitoring applications |
Applications
| Portable Power Rail Protection | Microcontroller I/O Clamp |
|---|---|
Use Scenario: Protecting 3.3 V or 5 V supply lines in smartphones and wearables against transient surges from USB charging or ESD events. IC Role / Device Role / Timing Role: Two-terminal shunt regulator absorbing excess energy during overvoltage conditions. Use Value: Limits voltage excursion to ≤41 V while drawing <70 nA in normal operation, preserving battery life and system reliability. |
Use Scenario: Clamping GPIO pins of ARM Cortex-M microcontrollers exposed to external sensors or connectors. IC Role / Device Role / Timing Role: Passive voltage limiter preventing latch-up or gate oxide damage during hot-plug events. Use Value: Responds within nanoseconds to transients up to 16 kV HBM, with 45 pF capacitance avoiding signal integrity degradation at 10 MHz clock rates. |
| Reference Voltage Source | Industrial Sensor Biasing |
Use Scenario: Generating stable 39 V reference for analog-to-digital converter (ADC) input scaling in data acquisition modules. IC Role / Device Role / Timing Role: Precision Zener element providing known voltage offset with predictable temperature drift (+27.3 mV/°C). Use Value: Enables 0.1% full-scale accuracy over −40°C to +85°C when paired with matched resistor dividers and temperature compensation. |
Use Scenario: Biasing bridge-based pressure or temperature sensors in factory automation transmitters. IC Role / Device Role / Timing Role: Stable excitation source maintaining constant sensor sensitivity across ambient temperature swings. Use Value: Delivers <100 ppm/°C effective stability when combined with low-TC resistors, reducing calibration drift in 4–20 mA loop outputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84C39LT1G | Same electrical specs but supplied in 3,000-piece tape-and-reel vs. 10,000-piece for BZX84C39LT3G; identical SOT-23 package and marking. | Preferred for prototyping or low-volume production where smaller reels reduce inventory holding cost. | Select BZX84C39LT1G when reel size constraints dominate; otherwise BZX84C39LT3G offers better unit cost and logistics efficiency. |
| MMBZ5267BLT1G | 36 V nominal Zener voltage (34.2–37.8 V range), tighter ±5% tolerance, 100 Ω ZZT at 20 mA, 100 pF capacitance - lower voltage, higher capacitance, different thermal coefficient (+25 mV/°C). | Better suited for 3.3 V rail clamping where lower breakdown voltage reduces stress on downstream components. | Choose MMBZ5267BLT1G only if 36 V regulation is acceptable; BZX84C39LT3G remains optimal for 39 V-specific reference or protection needs. |
Compared with BZX84C39LT1G, BZX84C39LT3G offers identical performance with optimized packaging for high-volume manufacturing; versus MMBZ5267BLT1G, it provides higher Zener voltage and lower capacitance, making it more suitable for 39 V reference stability and high-speed signal line protection.
Availability
BZX84C39LT3G is available at Aetrix Electronics and suitable for portable power rail protection, microcontroller I/O clamp, and industrial sensor biasing requiring stable component supply, consistent SOT-23 footprint, and automotive-grade reliability.
Supply support for BZX84C39LT3G 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and consumer markets.
The BZX84Cxxx series is part of onsemi's broad portfolio of discrete Zener regulators designed specifically for space-constrained, high-reliability voltage reference and transient suppression in portable and embedded electronics.
FAQ
What is the Zener voltage tolerance of BZX84C39LT3G?
The BZX84C39LT3G has a standard tolerance of ±5%, meaning its Zener voltage is guaranteed between 37 V and 41 V when tested at 5 mA reverse current and 25°C ambient temperature. This tolerance reflects the "C" suffix in the part number and is confirmed in the Electrical Characteristics table on page 3 of the onsemi datasheet.
Does BZX84C39LT3G have a connected pin 2?
No, BZX84C39LT3G has pin 2 designated as "No Connection" per the official onsemi datasheet. Pin 1 is the anode, pin 2 is internally unconnected and must remain floating on the PCB, and pin 3 is the cathode with polarity band identification. This configuration is standardized across the BZX84CxxxLTxG series.
What is the maximum reverse leakage current for BZX84C39LT3G?
The maximum reverse leakage current for BZX84C39LT3G is 70 nA, measured at a reverse voltage of 30.4 V (78% of nominal Zener voltage) and 25°C ambient temperature. This value is specified in the Electrical Characteristics table and confirms low standby power consumption essential for battery-operated devices.
Can BZX84C39LT3G be used in automotive applications?
The BZX84C39LT3G itself is not AEC-Q101 qualified; however, the SZBZX84C39LT3G variant - with identical electrical and mechanical specifications - is automotive-grade, AEC-Q101 qualified, and PPAP capable. For automotive use, specify the SZ-prefix version to ensure compliance with automotive reliability and traceability requirements.
What is the thermal resistance junction-to-ambient for BZX84C39LT3G?
The thermal resistance junction-to-ambient (RJA) for BZX84C39LT3G is 500 °C/W when mounted on an FR-5 board, as stated in the Maximum Ratings table. This value assumes standard JEDEC test conditions and must be derated by 2.0 mW/°C above 25°C ambient to maintain safe junction temperature below 150°C.
BZX84C39LT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- BZX84CxxxLT1G
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 250 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:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
BZX84C39LT3G FAQ
1.How can I place an order for BZX84C39LT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84C39LT3G 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 BZX84C39LT3G reliable?
The price and inventory of BZX84C39LT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84C39LT3G is usually 5 days.
3.What payment methods are accepted for BZX84C39LT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84C39LT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84C39LT3G?
BZX84C39LT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84C39LT3G 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 BZX84C39LT3G?
For technical support, including BZX84C39LT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84C39LT3G requirements.
6.How does Aetrix verify that BZX84C39LT3G is sourced from the original manufacturer or authorized distributors?
All BZX84C39LT3G 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 BZX84C39LT3G meets industry standards.
7.What is the process for return or replacement of BZX84C39LT3G?
All BZX84C39LT3G units undergo pre-shipment inspection (PSI). If there is an issue with BZX84C39LT3G, 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 BZX84C39LT3G part is unused and in its original packaging.
Return procedure for BZX84C39LT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84C39LT3G Tags
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