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Renesas RD18FM-T1-AY
- Part No.:
- RD18FM-T1-AY
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
RD18FM-T1-AY.pdf
- Description:
- DIODE ZENER 2-POWER MINI MOLD
- Quantity:
- Payment:
- Shipping:
Inventory:1,516
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Product details
Overview
RD18FM-T1-AY from Renesas Electronics is a 1 W, 16.8–19.1 V Zener diode in a planar-type 2-pin power mini mold package, designed for voltage regulation and surge suppression in industrial power rails and signal conditioning circuits. It delivers 5 mA test current, 45 Ω dynamic impedance at 5 mA, ≤10 μA reverse leakage at 13 V, and operates up to 150°C junction temperature.
For engineers reviewing the RD18FM-T1-AY datasheet, RD18FM-T1-AY pinout, RD18FM-T1-AY application, or RD18FM-T1-AY equivalent, this component serves as a precision voltage reference and transient clamp in DC power supplies, analog front-ends, and overvoltage protection stages where stable 18 V regulation and compact surface-mount form factor are required.
Technical Context
This Zener diode uses a planar silicon junction structure optimized for stable reverse breakdown with low dynamic impedance and predictable temperature coefficient behavior. Its 2-pin configuration supports flat-surface mounting and eliminates leadframe asymmetry issues common in 3-pin predecessors like RD**P series.
The device exhibits a typical Zener voltage temperature coefficient of +0.05 %/°C near 18 V (derived from Fig.3(a) interpolation), and maintains ≤10 μA reverse current up to 13 V - enabling reliable clamping without excessive standby leakage in battery-backed or low-power systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 16.8–19.1 V at IZ = 5 mA - defines regulated output range under nominal bias; usable as 18 V reference with ±6% tolerance. |
| Dynamic Impedance (ZZ) | 45 Ω max at IZ = 5 mA - ensures minimal voltage shift under load variation; suitable for moderate-precision regulation. |
| Reverse Current (IR) | ≤10 μA at VR = 13 V - enables low-leakage clamping below breakdown; avoids parasitic loading in high-impedance nodes. |
| Power Dissipation (P) | 1.0 W at TA = 25°C - supports continuous operation in PCB-mounted applications with adequate thermal relief (e.g., 30×8×0.7 mm ceramic substrate). |
| Surge Power (PRSM) | 400 W at t = 10 μs - withstands short-duration transients (e.g., ESD, inductive kickback) without degradation. |
| Junction Temperature (Tj) | −55 to +150°C - rated for extended industrial ambient ranges; requires thermal design consideration above 85°C ambient. |
Pinout & Package
RD18FM-T1-AY uses a 2-pin planar power mini mold package (SOD-123F equivalent footprint per dimensioning: 4.3 × 2.5 × 1.55 mm). Cathode is marked by a band on the body end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side connection | Connected to circuit ground or lower potential node during Zener operation; carries forward current up to 200 mA. |
| Cathode | Zener breakdown terminal / high-side connection | Connected to regulated or clamped node; sustains reverse voltage up to 19.1 V with controlled impedance and thermal stability. |
Key Features
| Feature | Design Value |
|---|---|
| Reduced mounting area | ~65% smaller footprint vs. legacy 3-pin RD**P series - enables higher board density in space-constrained industrial modules. |
| Flat-surface mount compatibility | Two-pin symmetric geometry eliminates orientation-dependent solder voiding - improves reflow yield in automated SMT lines. |
| Matched Zener classification | Same voltage grading (Class B) and test conditions as RD**P family - allows drop-in replacement in existing designs without recalibration. |
| High surge robustness | 400 W peak pulse power handling (10 μs) - protects downstream ICs from fast transients without external TVS cascading. |
Applications
| Industrial Power Supply Regulation | Analog Signal Clamping |
|---|---|
Use Scenario: Stabilizing 18 V auxiliary rail in programmable logic controller (PLC) I/O modules. IC Role / Device Role / Timing Role: Zener voltage reference and overvoltage limiter for op-amp bias networks and ADC reference buffers. Use Value: Maintains <±1% output deviation across −40 to +85°C ambient when paired with 1 kΩ series resistor; prevents latch-up in 3.3 V/5 V logic interfaces. |
Use Scenario: Protecting microcontroller GPIO pins from 24 V field wiring transients in factory automation sensors. IC Role / Device Role / Timing Role: Bidirectional transient suppressor (reverse-biased Zener + forward diode action) at signal input stage. Use Value: Limits excursion to ≤19.1 V during 100 ns spikes, reducing risk of ESD damage without adding propagation delay to analog feedback paths. |
| DC Motor Driver Voltage Clamp | Programmable Current Source Reference |
Use Scenario: Snubbing inductive kickback from 24 V brushed DC motor drivers in robotic joint controllers. IC Role / Device Role / Timing Role: Passive energy dissipation element placed across H-bridge outputs. Use Value: Absorbs 400 W surges for 10 μs without derating, eliminating need for larger TVS diodes or RC snubbers in compact motor driver PCBs. |
Use Scenario: Setting precise 18 V reference for constant-current LED driver ICs in industrial lighting control panels. IC Role / Device Role / Timing Role: Stable voltage source for current-sense amplifier bias and DAC reference scaling. Use Value: Enables ±2% current accuracy over temperature due to low 45 Ω ZZ and predictable TC; reduces calibration drift vs. resistor-divider references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | 1 W, 18 V nominal, 50 Ω ZZ, DO-41 package (5.2 × 2.7 mm) | Larger footprint and axial-lead assembly; higher thermal resistance (120°C/W vs. ~312°C/W for RD18FM-T1-AY on ceramic PCB) | Prefer RD18FM-T1-AY for SMT volume production; choose 1N4746A only if through-hole prototyping or legacy board reuse is required. |
| BZX84-C18 | 350 mW, 18 V nominal, 40 Ω ZZ, SOT-23 package (3.0 × 1.4 mm) | Lower power rating limits surge handling to ~100 W (t = 10 μs); unsuitable for motor driver clamping or 1 W continuous use | Select RD18FM-T1-AY where 1 W dissipation or 400 W transient absorption is mandatory; BZX84-C18 fits only low-power signal-level clamping. |
Compared with 1N4746A and BZX84-C18, RD18FM-T1-AY uniquely balances SMT manufacturability, 1 W continuous power, and 400 W surge capability in a 4.3 mm × 2.5 mm footprint - making it optimal for industrial power interface circuits where reliability and board space are jointly constrained.
Availability
RD18FM-T1-AY is available at Aetrix Electronics and suitable for industrial power supply regulation, analog signal clamping, and DC motor driver voltage clamp applications requiring stable component supply and long-term obsolescence management.
Supply support for RD18FM-T1-AY 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 specializing in microcontrollers, analog, power, and timing solutions for industrial, automotive, and infrastructure markets.
RD18FM-T1-AY belongs to Renesas' legacy Zener diode portfolio developed for high-reliability industrial voltage regulation and transient suppression - emphasizing thermal robustness, tight voltage grading, and SMT process compatibility.
FAQ
What is the Zener voltage tolerance of RD18FM-T1-AY?
The RD18FM-T1-AY has a Zener voltage range of 16.8 V to 19.1 V at 5 mA test current, corresponding to Class B grading per the datasheet. This ±6.2% tolerance reflects manufacturing spread and is verified under pulsed 40 ms conditions. Designers should use the min/max values - not nominal - when calculating worst-case regulation error in RD18FM-T1-AY-based circuits.
Can RD18FM-T1-AY be used in place of RD18FM without modification?
Yes, RD18FM-T1-AY is the tape-and-reel packaging variant of RD18FM, sharing identical electrical specifications, thermal characteristics, and package dimensions. The "-T1-AY" suffix denotes 3000-piece embossed carrier tape per JIS C 0601 standard; no circuit or layout changes are needed when substituting RD18FM-T1-AY for RD18FM in SMT production.
What is the maximum continuous power dissipation for RD18FM-T1-AY at 70°C ambient?
Per Figure 1 in the datasheet, RD18FM-T1-AY's power derating curve shows ~0.75 W maximum continuous dissipation at 70°C ambient on a 30×8×0.7 mm ceramic PCB. This assumes free-air convection; actual value depends on PCB copper area and airflow. Exceeding this limit risks exceeding the 150°C junction temperature rating of RD18FM-T1-AY.
Does RD18FM-T1-AY meet RoHS requirements?
Yes, RD18FM-T1-AY complies with EU RoHS Directive 2011/65/EU as confirmed by Renesas' environmental compliance documentation. It contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits. Full material declarations and test reports for RD18FM-T1-AY are available upon request from Aetrix Electronics.
How does the dynamic impedance of RD18FM-T1-AY affect voltage regulation stability?
The RD18FM-T1-AY's dynamic impedance of 45 Ω max at 5 mA means a 1 mA change in Zener current causes up to 45 mV output shift. For stable regulation, designers must ensure sufficient series resistance to maintain ≥5 mA Zener current across line/load variations - otherwise RD18FM-T1-AY's regulation accuracy degrades nonlinearly below that bias point.
RD18FM-T1-AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- -
- Tolerance:
- -
- Power - Max:
- -
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 2-Power Mini Mold
RD18FM-T1-AY FAQ
1.How can I place an order for RD18FM-T1-AY through Aetrix?
Please submit a Request for Quotation (RFQ) for RD18FM-T1-AY 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 RD18FM-T1-AY reliable?
The price and inventory of RD18FM-T1-AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD18FM-T1-AY is usually 5 days.
3.What payment methods are accepted for RD18FM-T1-AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD18FM-T1-AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD18FM-T1-AY?
RD18FM-T1-AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD18FM-T1-AY 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 RD18FM-T1-AY?
For technical support, including RD18FM-T1-AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD18FM-T1-AY requirements.
6.How does Aetrix verify that RD18FM-T1-AY is sourced from the original manufacturer or authorized distributors?
All RD18FM-T1-AY 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 RD18FM-T1-AY meets industry standards.
7.What is the process for return or replacement of RD18FM-T1-AY?
All RD18FM-T1-AY units undergo pre-shipment inspection (PSI). If there is an issue with RD18FM-T1-AY, 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 RD18FM-T1-AY part is unused and in its original packaging.
Return procedure for RD18FM-T1-AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD18FM-T1-AY Tags
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MMBZ5240B-7-F
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