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Renesas RD3.9F-T8-AZ
- Part No.:
- RD3.9F-T8-AZ
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD3.9F-T8-AZ.pdf
- Description:
- DIODE ZENER
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
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Product details
Overview
RD3.9F-T8-AZ from Renesas Electronics is a 1 W planar-type silicon Zener diode in DO-41 glass-sealed DHD package, with nominal zener voltage 3.9 V (B2 grade: 3.88–4.15 V), dynamic impedance ≤40 Ω at 15 mA, and temperature coefficient −2.5 mV/°C. It serves as a precision voltage reference and overvoltage clamp in low-power analog power rails.
For engineers reviewing the RD3.9F-T8-AZ datasheet, RD3.9F-T8-AZ pinout, RD3.9F-T8-AZ application, or RD3.9F-T8-AZ equivalent, this page delivers verified electrical specs, thermal derating curves, surge capability (400 W @ 10 μs), and direct substitution guidance for industrial and consumer-grade voltage regulation circuits.
Technical Context
This device operates as a two-terminal reverse-biased voltage regulator with stable breakdown behavior under DC and transient conditions. Its planar junction structure ensures consistent VZ tolerance and low dynamic impedance across production lots.
The RD3.9F-T8-AZ exhibits a negative temperature coefficient (−2.5 mV/°C), making it suitable for temperature-compensated references when paired with positive-TC components. Its 175°C maximum junction temperature and DO-41 thermal profile support operation in compact PCB layouts with minimal heatsinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.88–4.15 V at IZ = 15 mA - defines tight regulation window for 3.3 V system biasing |
| Power Dissipation (P) | 1.0 W at TA = 25°C - supports continuous operation up to ~70°C ambient with standard PCB copper |
| Dynamic Impedance (ZZ) | ≤40 Ω at IZ = 15 mA - ensures minimal output voltage shift under load transients |
| Reverse Current (IR) | ≤40 μA at VR = 1.0 V - guarantees low leakage in standby-sensitive circuits |
| Temp. Coefficient (γZ) | −2.5 mV/°C - enables predictable drift compensation in reference designs |
| Surge Power (PRSM) | 400 W at t = 10 μs - clamps ESD and inductive spikes without failure |
| Junction Temp. (Tj) | 175°C max - allows use in thermally constrained enclosures with adequate trace width |
Pinout & Package
RD3.9F-T8-AZ uses the JEDEC DO-41 axial glass package (3.0 mm Ø × 5.0 mm L) with cathode indicated by black band. The device has two terminals: anode and cathode - no internal connections or control pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-bias regulation configuration |
| Cathode | Zener breakdown terminal | Marked with black band; connected to regulated voltage rail or clamp point |
Key Features
| Feature | Design Value |
|---|---|
| Wide VZ range coverage | Part of RD2.0F–RD82F family spanning 2–82 V, enabling standardized BOM across multiple voltage rails |
| E24 nominal voltage series | Ensures compatibility with common resistor ladder and feedback network values in analog design |
| DHD (Double Heatsink Diode) structure | Enhanced thermal dissipation via dual heat path through leads, improving reliability under pulsed loads |
| DO-41 glass seal | Hermetic protection against moisture and contaminants, supporting long-term stability in non-hermetic assemblies |
Applications
| Power Supply Reference | Waveform Clipping |
|---|---|
Use Scenario: Providing stable 3.9 V reference for op-amp biasing or ADC voltage divider in battery-powered sensor nodes. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference regulating local analog supply. Use Value: Maintains ±1.5% output accuracy over 0–70°C due to low ZZ and controlled γZ. | Use Scenario: Limiting audio signal peaks in line-level preamplifier input stage to prevent op-amp saturation. IC Role / Device Role / Timing Role: Bidirectional voltage limiter using forward + reverse conduction thresholds. Use Value: Clamps asymmetrical waveforms at ±3.9 V/±0.7 V with <10 ns response to fast transients. |
| Surge Protection | Constant-Current Bias |
Use Scenario: Absorbing inductive kickback from relay coils in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Transient voltage suppressor placed across coil terminals. Use Value: Withstands 400 W surges (10 μs) without degradation, extending relay driver lifetime. | Use Scenario: Setting precise LED bias current in status indicator circuits using resistor-Zener combination. IC Role / Device Role / Timing Role: Stable voltage source enabling constant-current mirror configuration. Use Value: Delivers <±2% current variation over 5–30 V input range due to low ZZ and tight VZ tolerance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4733A | Same 5.1 V nominal rating but different VZ tolerance (±5% vs. RD3.9F-T8-AZ's ±3.5%), higher ZZ (17 Ω vs. 40 Ω at rated IZ) | Designed for general-purpose 5.1 V regulation; not a drop-in replacement for 3.9 V systems | Select only if redesigning for 5.1 V reference and accepting wider VZ spread |
| BZX55-C3V9 | Identical 3.9 V nominal rating, same DO-41 package, but higher ZZ (90 Ω max at 5 mA) and lower PRSM (100 W) | Suitable for low-energy clamping; insufficient for high-surge industrial environments | Acceptable for cost-sensitive consumer designs where surge immunity is secondary |
Compared with RD3.9F-T8-AZ, the 1N4733A targets a different voltage class and lacks matching thermal/surge specs, while BZX55-C3V9 shares the voltage grade but sacrifices transient robustness and regulation precision-making RD3.9F-T8-AZ preferable for demanding industrial reference and protection roles.
Availability
RD3.9F-T8-AZ is available at Aetrix Electronics and suitable for industrial control systems, consumer power adapters, and automotive body electronics requiring stable component supply and long-lifecycle support.
Supply support for RD3.9F-T8-AZ 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
Renesas Electronics Corporation is a global semiconductor leader formed in 2010 via merger of NEC Electronics and Renesas Technology, specializing in microcontrollers, analog, and power devices.
The RD series Zener diodes were developed for high-reliability voltage regulation and transient suppression in standard-grade industrial and consumer equipment, emphasizing consistency, thermal resilience, and long-term parametric stability.
FAQ
What is the exact zener voltage tolerance for RD3.9F-T8-AZ?
The RD3.9F-T8-AZ has a B2 grade zener voltage specification of 3.88 V minimum to 4.15 V maximum at test current IZ = 15 mA, corresponding to ±3.5% tolerance around the nominal 3.9 V rating. This tolerance is verified per Renesas datasheet D13936EJ5V0DS, Section "ELECTRICAL CHARACTERISTICS".
Does RD3.9F-T8-AZ support surge protection applications?
Yes, RD3.9F-T8-AZ is rated for 400 W surge reverse power at 10 μs pulse width (PRSM), making it suitable for absorbing inductive switching transients and ESD events. Its DO-41 DHD structure and 175°C junction rating ensure survivability in repetitive surge scenarios typical in relay drivers and motor controls.
What is the thermal resistance characteristic of RD3.9F-T8-AZ?
RD3.9F-T8-AZ exhibits transient thermal impedance of ~150°C/W at 10 ms (per Figure 8), with steady-state derating beginning above 25°C ambient. At 70°C ambient, its usable power drops to ~0.7 W - confirmed by the P vs. TA curve in Figure 1 of the official datasheet.
Is RD3.9F-T8-AZ RoHS compliant?
Yes, RD3.9F-T8-AZ complies with EU RoHS Directive requirements as confirmed by Renesas Electronics' environmental documentation. The device contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits, and is marked accordingly in production lots post-2006.
Can RD3.9F-T8-AZ be used in place of a 3.3 V reference?
No - RD3.9F-T8-AZ is specified at 3.9 V nominal (3.88–4.15 V), not 3.3 V. Substituting it for a true 3.3 V zener would cause over-regulation and potential circuit malfunction. For 3.3 V applications, Renesas offers RD3.3F (3.13–3.51 V), which is the correct family member.
RD3.9F-T8-AZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- -
- Tolerance:
- -
- Power - Max:
- -
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
RD3.9F-T8-AZ FAQ
1.How can I place an order for RD3.9F-T8-AZ through Aetrix?
Please submit a Request for Quotation (RFQ) for RD3.9F-T8-AZ 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 RD3.9F-T8-AZ reliable?
The price and inventory of RD3.9F-T8-AZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD3.9F-T8-AZ is usually 5 days.
3.What payment methods are accepted for RD3.9F-T8-AZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD3.9F-T8-AZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD3.9F-T8-AZ?
RD3.9F-T8-AZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD3.9F-T8-AZ 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 RD3.9F-T8-AZ?
For technical support, including RD3.9F-T8-AZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD3.9F-T8-AZ requirements.
6.How does Aetrix verify that RD3.9F-T8-AZ is sourced from the original manufacturer or authorized distributors?
All RD3.9F-T8-AZ 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 RD3.9F-T8-AZ meets industry standards.
7.What is the process for return or replacement of RD3.9F-T8-AZ?
All RD3.9F-T8-AZ units undergo pre-shipment inspection (PSI). If there is an issue with RD3.9F-T8-AZ, 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 RD3.9F-T8-AZ part is unused and in its original packaging.
Return procedure for RD3.9F-T8-AZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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