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Renesas RD18F-T6
- Part No.:
- RD18F-T6
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD18F-T6.pdf
- Description:
- DIODE ZENER
- Quantity:
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- Shipping:
Inventory:4,370
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Product details
Overview
RD18F-T6 from Renesas Electronics is a 1 W planar-type silicon Zener diode with a nominal zener voltage of 18 V (B3 grade: 17.64–18.55 V), dynamic impedance of 12 Ω at 20 mA, and temperature coefficient of +15 mV/°C. It features DO-41 glass-sealed DHD (Double Heatsink Diode) packaging and is rated for surge reverse power up to 400 W (10 μs pulse), making it suitable for overvoltage protection in industrial power supply rails.
For engineers reviewing the RD18F-T6 datasheet, RD18F-T6 pinout, RD18F-T6 application, or RD18F-T6 equivalent, this device serves as a precision voltage reference and transient suppressor in DC bias networks, feedback loops of linear regulators, and input-stage surge clamping circuits where stable 18 V regulation and low dynamic impedance are required.
Technical Context
This Zener diode operates in reverse breakdown mode with a specified test current (IZ) of 20 mA, delivering tight voltage tolerance (±3.0% for B3 grade) and low dynamic impedance (12 Ω) to maintain regulation under varying load conditions. Its positive temperature coefficient (+15 mV/°C) enables predictable drift behavior in temperature-critical biasing applications.
The DO-41 package provides robust thermal performance with a junction-to-ambient thermal resistance of ~200 °C/W (at 5 mm PCB copper area), and its glass-sealed DHD structure ensures reliable operation across −65°C to +175°C storage and operating ranges. Surge capability is validated per Figure 7: 400 W for 10 μs pulses at TA = 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.64–18.55 V (B3 grade, tested at 20 mA); ensures precise 18 V reference with ±3.0% tolerance in feedback or clamp circuits. |
| Power Dissipation (P) | 1.0 W continuous at TA = 25°C; supports sustained regulation in low-to-medium power analog stages without forced cooling. |
| Dynamic Impedance (ZZ) | 12 Ω at IZ = 20 mA; minimizes output voltage variation under load transients in voltage reference applications. |
| Temperature Coefficient (γZ) | +15 mV/°C (typical); enables predictable, monotonic voltage drift for temperature-compensated designs. |
| Surge Reverse Power (PRSM) | 400 W (t = 10 μs); absorbs short-duration ESD or inductive kick energy without failure in unprotected input nodes. |
| Junction Temperature (Tj) | 175°C maximum; allows operation in high-ambient industrial environments when properly heatsinked. |
| Reverse Current (IR) | ≤10 μA at VR = 14.4 V; guarantees low leakage in high-impedance bias networks. |
Pinout & Package
RD18F-T6 uses a DO-41 axial-leaded glass 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 / reference ground node in reverse-biased configuration | Connected to lower-potential side of circuit; forms return path during Zener conduction. |
| Cathode | Zener breakdown terminal / regulated output node | Marked with black band; connected to higher-potential rail to establish 18 V reference or clamp level. |
Key Features
| Feature | Design Value |
|---|---|
| 1 W Planar Zener Structure | Enables stable, repeatable breakdown characteristics and long-term voltage stability under continuous DC stress. |
| E24-Series Voltage Standardization | Supports interoperability with common design libraries and simplifies BOM consolidation across 2–82 V Zener families. |
| DO-41 Glass-Sealed DHD Package | Provides mechanical ruggedness, hermetic reliability, and dual heatsinking paths via axial leads and body contact. |
| B3 Voltage Grade Tight Tolerance | Delivers 17.64–18.55 V range (±3.0%) - tighter than generic B-grade parts - for improved system-level accuracy. |
| Positive Temperature Coefficient | +15 mV/°C enables predictable compensation when paired with negative-TC components (e.g., transistors) in bias networks. |
Applications
| Industrial Power Supply Clamp | Linear Regulator Feedback Reference |
|---|---|
Use Scenario: Clamping 24 V DC input rail against load-dump transients in PLC I/O modules. IC Role / Device Role / Timing Role: Zener diode operating in reverse breakdown to limit peak voltage to ≤18.55 V, protecting downstream LDOs and microcontrollers. Use Value: Absorbs 400 W surges (10 μs) without degradation, eliminating need for TVS diodes in cost-sensitive industrial designs. |
Use Scenario: Setting output voltage of adjustable 3-terminal linear regulator (e.g., LM317) in sensor signal conditioning circuit. IC Role / Device Role / Timing Role: Precision voltage reference element in feedback divider network, defining regulated 18 V output. Use Value: 12 Ω dynamic impedance ensures <10 mV output shift under 10 mA load change, improving load regulation accuracy. |
| DC Bias Network Stabilizer | Overvoltage Protection in Analog Front-End |
Use Scenario: Establishing stable bias point for op-amp input stage in 24 V-powered instrumentation amplifier. IC Role / Device Role / Timing Role: Zener shunt providing fixed 18 V reference to high-impedance node, compensating for supply ripple. Use Value: +15 mV/°C TC allows predictable tracking with amplifier offset drift, reducing calibration frequency in field-deployed units. |
Use Scenario: Protecting ADC input of microcontroller-based data logger exposed to 24 V field wiring. IC Role / Device Role / Timing Role: Primary clamping device limiting input voltage to safe levels before series current-limiting resistor. Use Value: Low 10 μA leakage at 14.4 V prevents signal attenuation in high-Z sensor interfaces while maintaining fast response to overvoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | Zener voltage 18 V (17.1–18.9 V), 1 W, DO-41, ZZ = 20 Ω @ 19 mA, γZ = +12 mV/°C | Wider voltage tolerance (±5%), higher dynamic impedance reduces regulation fidelity in precision references. | Acceptable for non-critical clamping where cost is primary; not recommended for feedback references requiring <15 mV load shift. |
| BZX85C18 | Zener voltage 18 V (17.1–18.9 V), 1.3 W, DO-41, ZZ = 20 Ω @ 5 mA, γZ = +12 mV/°C, higher Ptot | Higher power rating but looser initial tolerance and less stable TC; optimized for general-purpose use, not precision biasing. | Suitable for higher-power surge suppression; inferior for temperature-stable references due to TC mismatch and wider VZ spread. |
Compared with RD18F-T6, both 1N4746A and BZX85C18 offer similar DO-41 form factor and 18 V nominal rating but lack its B3-grade tight tolerance (±3.0%), low 12 Ω dynamic impedance, and precisely characterized +15 mV/°C temperature coefficient - critical for high-accuracy analog bias and regulation tasks.
Availability
RD18F-T6 is available at Aetrix Electronics and suitable for industrial power supply clamp, linear regulator feedback reference, and DC bias network stabilizer applications requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for RD18F-T6 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, and advanced SoCs for industrial, automotive, and infrastructure markets.
RD18F-T6 belongs to Renesas' legacy planar Zener diode family designed for high-reliability voltage regulation and transient suppression in industrial control, instrumentation, and power management systems.
FAQ
What is the exact zener voltage range for RD18F-T6?
The RD18F-T6 is specified as a B3-grade device with a zener voltage range of 17.64 V to 18.55 V at 20 mA test current, per Renesas Data Sheet D13936EJ5V0DS. This ±3.0% tolerance is tighter than standard B-grade parts and ensures consistent performance in precision reference applications where RD18F-T6 is deployed.
Does RD18F-T6 have a defined polarity marking, and how is it identified?
Yes, RD18F-T6 uses a DO-41 package with a black cathode band clearly marked on the glass body. The banded end is the cathode, and the unmarked end is the anode - consistent with JEDEC DO-41 conventions and confirmed in the package drawing of Renesas' datasheet. This marking is essential for correct orientation in reverse-bias regulation circuits using RD18F-T6.
What is the maximum surge reverse power rating for RD18F-T6, and under what conditions?
RD18F-T6 is rated for 400 W surge reverse power at a pulse width of 10 μs and ambient temperature of 25°C, as shown in Figure 7 of the official datasheet. This rating applies to single, non-repetitive events and reflects the device's ability to absorb transient energy without parametric shift or failure - a key specification for RD18F-T6 in input-stage protection roles.
How does the temperature coefficient of RD18F-T6 affect its performance in bias circuits?
RD18F-T6 exhibits a typical zener voltage temperature coefficient of +15 mV/°C, meaning its regulated voltage increases predictably with temperature. In bias networks, this allows designers to compensate for negative-TC elements (e.g., transistor VBE) - a feature explicitly leveraged in stable reference designs where RD18F-T6 is used for temperature-aware calibration.
Is RD18F-T6 compliant with RoHS and lead-free assembly requirements?
RD18F-T6 is manufactured in compliance with EU RoHS Directive requirements, as confirmed by Renesas Electronics' environmental policy statements and product declarations. The device supports lead-free reflow soldering processes and contains no restricted substances above threshold limits - a requirement verified for RD18F-T6 in industrial production environments.
RD18F-T6 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:
- -
RD18F-T6 FAQ
1.How can I place an order for RD18F-T6 through Aetrix?
Please submit a Request for Quotation (RFQ) for RD18F-T6 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 RD18F-T6 reliable?
The price and inventory of RD18F-T6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD18F-T6 is usually 5 days.
3.What payment methods are accepted for RD18F-T6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD18F-T6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD18F-T6?
RD18F-T6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD18F-T6 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 RD18F-T6?
For technical support, including RD18F-T6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD18F-T6 requirements.
6.How does Aetrix verify that RD18F-T6 is sourced from the original manufacturer or authorized distributors?
All RD18F-T6 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 RD18F-T6 meets industry standards.
7.What is the process for return or replacement of RD18F-T6?
All RD18F-T6 units undergo pre-shipment inspection (PSI). If there is an issue with RD18F-T6, 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 RD18F-T6 part is unused and in its original packaging.
Return procedure for RD18F-T6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD18F-T6 Tags
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