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Renesas RD3.9F-AZ
- Part No.:
- RD3.9F-AZ
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD3.9F-AZ.pdf
- Description:
- DIODE ZENER
- Quantity:
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- Shipping:
Inventory:13,900
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Product details
Overview
RD3.9F-AZ from Renesas Electronics is a 1 W planar silicon Zener diode in DO-41 glass-sealed DHD package, with nominal zener voltage 3.9 V (B grade: 3.73–4.15 V), dynamic impedance ≤40 Ω at 15 mA, and temperature coefficient −2.5 mV/°C. It operates as a precision voltage reference or surge clamp in low-voltage power rails and signal conditioning circuits.
For engineers reviewing the RD3.9F-AZ datasheet, RD3.9F-AZ pinout, RD3.9F-AZ application, or RD3.9F-AZ equivalent, this part serves as a standardized, E24-series zener for voltage regulation, waveform limiting, and transient suppression in industrial and consumer electronics where stable 3.9 V reference or clamping is required.
Technical Context
The RD3.9F-AZ uses a planar junction structure with double heatsink (DHD) design to achieve thermal robustness and stable zener characteristics across ambient temperatures up to +175°C. Its 1 W power rating is derated linearly above +25°C per Figure 1, with thermal resistance dependent on PCB copper area.
It exhibits low dynamic impedance (≤40 Ω at IZ = 15 mA) and tightly controlled reverse leakage (≤40 μA at VR = 1.0 V), enabling accurate voltage stabilization in feedback loops and low-current bias networks. The −2.5 mV/°C temperature coefficient ensures predictable drift behavior near room temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.73–4.15 V at IZ = 40 mA - defines clamping threshold and reference accuracy under standard test conditions. |
| Power Dissipation (P) | 1.0 W at TA = 25°C - sets maximum continuous DC or average pulsed power handling before thermal runaway. |
| Dynamic Impedance (ZZ) | ≤40 Ω at IZ = 15 mA - determines regulation stiffness and output voltage variation under load current changes. |
| Reverse Current (IR) | ≤40 μA at VR = 1.0 V - ensures minimal leakage in high-impedance bias or sensing nodes. |
| Temperature Coefficient (γZ) | −2.5 mV/°C (typ.) - quantifies voltage drift per degree, critical for temperature-sensitive references. |
| Junction Temperature (Tj) | 175°C maximum - defines upper thermal limit for reliable operation and lifetime estimation. |
| Surge Reverse Power (PRSM) | 400 W at t = 10 μs - supports transient overvoltage absorption without failure in surge-prone interfaces. |
Pinout & Package
RD3.9F-AZ is housed in a DO-41 glass-sealed axial package (JEDEC standard), with cathode indicated by a black band. The device has two terminals: anode and cathode - no internal circuitry or additional pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connects to lower-potential node in reverse-biased zener configuration; carries forward current up to 200 mA. |
| Cathode | Zener breakdown terminal | Marked with black band; connects to higher-potential node; defines regulated voltage at cathode relative to anode. |
Key Features
| Feature | Design Value |
|---|---|
| E24-series zener voltage grading | Enables standardized BOM consolidation across 2–82 V range without custom voltage bins. |
| DO-41 glass-sealed DHD construction | Provides mechanical ruggedness and consistent thermal path for 1 W dissipation in compact axial form. |
| Low-temperature-coefficient option | −2.5 mV/°C typical enables tighter system-level voltage stability vs. generic 3.9 V zeners with ±5 mV/°C drift. |
| Controlled dynamic impedance | ≤40 Ω at 15 mA supports stable regulation in feedback paths of LDOs and voltage monitors. |
| High surge tolerance | 400 W peak reverse power (10 μs) allows use in I/O protection without external TVS stacking. |
Applications
| Power Supply Voltage Reference | Signal-Level Waveform Clipping |
|---|---|
Use Scenario: Providing stable 3.9 V reference for ADC voltage dividers or op-amp biasing in battery-powered sensor nodes. IC Role / Device Role / Timing Role: Passive voltage reference element establishing precise analog ground-referenced threshold. Use Value: Enables <1% full-scale error in 12-bit ADC systems without trimming, leveraging tight VZ tolerance and low ZZ. |
Use Scenario: Limiting analog audio signal peaks to ±3.9 V before input to microcontroller GPIO with 5 V tolerant inputs. IC Role / Device Role / Timing Role: Bidirectional clamping diode (with series resistor) protecting input stage from overvoltage transients. Use Value: Prevents latch-up and ESD damage while preserving signal fidelity below clipping threshold due to low ZZ and fast response. |
| DC Rail Surge Suppression | Constant-Current Bias Generator |
Use Scenario: Absorbing inductive kickback from 12 V relay coils in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Transient voltage suppressor placed across coil, conducting only during >3.9 V spikes. Use Value: Handles 400 W surges (10 μs) without degradation, eliminating need for larger TVS diodes in space-constrained designs. |
Use Scenario: Generating ~15 mA constant current for LED biasing or phototransistor collector loads in optical encoders. IC Role / Device Role / Timing Role: Zener-based current source using RD3.9F-AZ in series with current-setting resistor. Use Value: Delivers stable current over temperature (−2.5 mV/°C γZ) and supply variation, reducing calibration burden in factory-set devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4733A | Same 5.1 V nominal rating but different VZ range (4.8–5.4 V); higher ZZ (≤17 Ω); RoHS-compliant packaging. | Not interchangeable for 3.9 V requirement; suitable only if system tolerates 5.1 V reference. | Select only if redesign permits 5.1 V instead of 3.9 V and lower ZZ is beneficial. |
| BZX55-C3V9 | 3.9 V nominal (3.7–4.1 V), 500 mW rating, DO-35 package; ZZ ≤90 Ω at 5 mA; wider VZ tolerance. | Lower power rating limits use in >0.5 W continuous applications; smaller DO-35 footprint reduces thermal mass. | Acceptable for low-power signal clamping where 1 W capability is unnecessary and board space is constrained. |
Compared with RD3.9F-AZ, the 1N4733A shifts reference voltage by +1.2 V and requires circuit redesign, while BZX55-C3V9 sacrifices 50% power margin and thermal stability for size reduction - making RD3.9F-AZ optimal for 3.9 V, 1 W, industrial-grade regulation where reliability and thermal headroom are prioritized.
Availability
RD3.9F-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-term obsolescence management.
Supply support for RD3.9F-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 manufacturer specializing in microcontrollers, analog, and power devices for industrial, automotive, and infrastructure markets.
RD3.9F-AZ belongs to the RD2.0F–RD82F planar zener diode family, designed for standardized voltage reference, clamping, and surge suppression in cost-sensitive, high-volume applications across consumer and industrial electronics.
FAQ
What is the exact zener voltage tolerance for RD3.9F-AZ?
The RD3.9F-AZ has a B-grade zener voltage range of 3.73 V to 4.15 V when tested at IZ = 40 mA, per Renesas datasheet D13936EJ5V0DS. This 10.7% tolerance reflects the E24-series standardization and is verified under 40 ms pulse conditions. RD3.9F-AZ does not offer tighter binning (e.g., B1/B2/B3) unless specifically ordered.
Can RD3.9F-AZ be used in surface-mount designs?
No - RD3.9F-AZ uses a through-hole DO-41 axial package with lead-forming dimensions specified in the datasheet. It lacks SMD variants (e.g., SOD-123 or SMA). For surface-mount equivalents, consider Renesas' NSZ series or third-party SOD-123 zeners with matching 3.9 V rating and 1 W rating, but verify thermal performance and ZZ independently.
What is the maximum allowable reverse voltage before breakdown for RD3.9F-AZ?
RD3.9F-AZ begins controlled zener breakdown at its specified VZ range (3.73–4.15 V). Below VZ, reverse leakage remains ≤40 μA at VR = 1.0 V. Operation above VZ is intentional and safe up to P = 1 W (derated with temperature); sustained reverse voltage significantly above VZ without current limiting will exceed power rating and cause thermal failure.
Does RD3.9F-AZ meet RoHS requirements?
Yes - RD3.9F-AZ complies with EU RoHS Directive 2011/65/EU, as confirmed by Renesas' environmental compliance documentation. The device contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits. Marking "AZ" in the suffix denotes RoHS-compliant packaging and processing.
How does the −2.5 mV/°C temperature coefficient affect RD3.9F-AZ in a 0–70°C operating range?
Over 0–70°C, RD3.9F-AZ's zener voltage drifts by approximately −175 mV (−2.5 mV/°C × 70°C), resulting in a VZ shift from ~4.07 V at 0°C to ~3.90 V at 70°C. This 4.3% variation must be accounted for in precision references; however, it remains predictable and monotonic, supporting calibration compensation in closed-loop systems using RD3.9F-AZ.
RD3.9F-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-AZ FAQ
1.How can I place an order for RD3.9F-AZ through Aetrix?
Please submit a Request for Quotation (RFQ) for RD3.9F-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-AZ reliable?
The price and inventory of RD3.9F-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-AZ is usually 5 days.
3.What payment methods are accepted for RD3.9F-AZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD3.9F-AZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD3.9F-AZ?
RD3.9F-AZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD3.9F-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-AZ?
For technical support, including RD3.9F-AZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD3.9F-AZ requirements.
6.How does Aetrix verify that RD3.9F-AZ is sourced from the original manufacturer or authorized distributors?
All RD3.9F-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-AZ meets industry standards.
7.What is the process for return or replacement of RD3.9F-AZ?
All RD3.9F-AZ units undergo pre-shipment inspection (PSI). If there is an issue with RD3.9F-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-AZ part is unused and in its original packaging.
Return procedure for RD3.9F-AZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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